Mike Conley
The McDowell News
Fri, 02 Nov 2007 14:17 EDT
Nearly a century ago, a tremendous explosion rocked the remote
forests of Siberia. To this day, the weird event is considered to be
one of the world's greatest unsolved mysteries.
On the morning of June 30, 1908, a massive explosion occurred in the
air above the remote, isolated forests near the Stony Tunguska River in
Siberia, Russia. For that reason, it is often called the Tunguska event.
The blast was estimated to be between 10 and 20 megatons of TNT --
1,000 times more powerful than the atomic bombs dropped on Hiroshima
and Nagasaki in 1945. The explosion felled an estimated 80 million
trees over an area of 830 square miles. The shock wave is estimated to
have measured 5.0 on the Richter scale, according to a Web site.
One eyewitness who lived about 40 miles south of the explosion
described the sky being "split in two" and fire appearing high and wide
over the vast forest.
"At that moment, I became so hot that I couldn't bear it, as if my
shirt was on fire; from the northern side, where the fire was, came
strong heat," the witness said. "I wanted to tear off my shirt and
throw it down, but then the sky shut closed, and a strong thump
sounded, and I was thrown a few yards. I lost my senses for a moment,
but then my wife ran out and led me to the house.
"After that such noise came, as if rocks were falling or cannons
were firing, the earth shook, and when I was on the ground, I pressed
my head down, fearing rocks would smash it. When the sky opened up, hot
wind raced between the houses, like from cannons, which left traces in
the ground like pathways, and it damaged some crops. Later we saw that
many windows were shattered, and in the barn a part of the iron lock
snapped."
That account is only one of many from the Siberian villagers who
were around to experience the enormous blast. Some of them were
convinced that the explosion signaled the end of the world and the
final judgment. It is fortunate that the explosion happened in a
remote, unpopulated area. If it had occurred over a major city, there
is no doubt that the city would have been utterly destroyed and
millions of people killed.
But how could such an explosion happen 37 years before the invention of the atomic bomb?
Because the Tunguska region was so isolated, the first recorded
expedition to the site didn't happen until the 1920s. Russian scientist
Leonid Kulik first journeyed to the site in 1921 and spoke to local
people who saw and felt the blast. He deduced that the explosion had
been caused by a giant meteorite impact. He persuaded the Soviet
government to fund an expedition to the Tunguska region.
Kulik's party finally reached the site in 1927. To their surprise,
no crater was to be found. Instead, a vast region of downed trees was
found stretching about 30 miles across. Later expeditions would further
explore the region devastated by the blast. It is interesting to note
that no elevated levels of radiation, which are typical of nuclear
explosions, have been found at the site.
Today many scientists believe that the Tunguska event was caused by
a meteor or comet which blew up just prior to hitting the Earth's
surface. It is often used as an example of what could happen if a
meteor or comet were to hit the Earth today, especially over a large
metropolitan area.
But others are not sure about that explanation. Some believe that
the Tunguska event was caused by the explosion of an alien spaceship.
In 1998, a TV show on Turner Network Television referred to the
Tunguska event as the "Russian Roswell" and claimed that UFO debris has
been recovered from the site. In 2004, a group of Russian UFO
enthusiasts claimed to have found the wreck of an alien spacecraft at
the blast site.
So today, the Tunguska event remains as one of the strangest
episodes in history. And we can only pray that something like that
doesn't happen over a populated area.
Contact Mike Conley at 652-3313, ext. 3422 or e-mail nconley@mcdowellnews.com
Richard L. Hill
The Oregonian
Thu, 01 Nov 2007 05:51 EDT
Overhunting. Abrupt climate change. Disease.
Scientists have cited those and other theories in their decades-old
debate about why mammoths, mastodons, sloths, saber-toothed cats,
camels, horses and other large creatures disappeared from North America
at the end of the last ice age.
The researchers say the impact also may have wiped out or fragmented
the prehistoric Clovis people who flourished in North America at the
time.
UO archaeologists Douglas Kennett and Jon Erlandson are among about
two dozen scientists who say the impact also could have led to the
abrupt cooling known as the Younger Dryas, which lasted 1,200 years.
"I initially thought this idea for a comet impact was preposterous,"
Erlandson said. "But as I started reviewing the data from multiple
locations, the concept began to capture my imagination. There was
dramatic change going on at that time. A comet contributing to that
change is just a hypothesis at this point, and it's probably going to
take at least 10 more years of research to figure out if that occurred."
The researchers laid out their proposed theory recently in the
Proceedings of the National Academy of Sciences. They say the evidence
is in a 2-inch-thick carbon-rich black mat found in about 50 sites
across North America.
Their article says the layer contains grains with iridium, carbon
spherules and fullerenes packed with concentrations of helium 3 -- "all
of which are evidence for an extraterrestrial impact" about 12,900
years ago and the raging wildfires that followed.
The scientists studied samples of black mats from 10 Clovis
archaeological sites in Canada, California, Arizona and South Carolina.
Evidence of mammoths and other animals and early human hunters are
found beneath the black mat but are missing within or above the strip.
They suggest that heat from the detonation or impact may have set
off wildfires across the continent and destabilized the vast Laurentide
Ice Sheet that covered much of Canada and the northern United States.
The melting of ice may have led to a flood of fresh water, changing
ocean currents in the North Atlantic and contributing to the cooling
climate that reduced human populations and added to the demise of the
animals.
No giant crater has been found from the impact, but the scientists
say the comet may have broken into smaller pieces and detonated in
various places.
"If a comet hit the Laurentide Ice Sheet, it would not have left a
big crater," Erlandson said. "It's ice on ice, and it's going to throw
up enormous amounts of shattered ice and debris."
Geological features known as Carolina Bays -- hundreds of thousands
of small depressions from New Jersey to Florida -- may have been caused
by the disintegrating object. Samples from 15 of the depressions
contained the iridium-rich magnetic grains and carbon spherules.
The elliptical depressions are oriented in a northwest-southeast
direction that point toward Canada and the Great Lakes, suggesting the
object disintegrated in that area.
"The initial impact would have been very heavy in eastern North
America, and western North America would have been more of a refuge,"
Erlandson said. "Some of the initial modeling of this impact indicated
that it would have created an enormous rolling fireball and force wave
that engulfed the entire continent and wiped out everything.
Archaeology tells us that it didn't do that; there were animals and
people that survived."
Erlandson said the reduced populations of large animals in the West
probably would have been under tremendous pressure from changes in the
environment and from hunting by remnants of Clovis populations.
The tell-tale black mats have not been found in the Northwest,
Kennett said, but scientists "have some leads on sites to visit and
sample." They include a site near Mill Creek in Woodburn's Legion Park,
where a treasure trove of remains from extinct ice age mammals has been
uncovered in recent years.
His father, James Kennett, a paleoceanographer at the University of
California at Santa Barbara, introduced the impact idea with Richard
Firestone of the Lawrence Berkeley National Laboratory and Allen West,
an Arizona researcher.
Douglas Kennett is in Spain looking for potential effects of the
impact in Europe and soon will look at sites in the Netherlands.
One of the archaeological sites being investigated is about 30 miles
off the Southern California coast on Daisy Island, where Erlandson has
uncovered evidence that humans used the islands about 13,000 years ago.
Erlandson plans to return to the island with other researchers to
determine whether there's additional evidence that would support the
comet impact concept.
Idea has its critics
The new hypothesis already has drawn critics.
"I think we would all like to see a smoking gun," said Alison
Stenger, a Portland archaeologist who has led excavations in Woodburn
and McMinnville that have turned up ice age animals. "We have not seen
any evidence of a black mat at these sites, and we've examined a lot of
sediment."
Not all large animals died off at the end of the ice age, and many
"were alive and well" at Woodburn and Rancho La Brea tar pits in Los
Angeles nearly 2,000 years after the proposed impact.
"I'm convinced that a group of things led to the extinction of these
animals," she said. "A comet certainly would be tidy explanation, but
I'm not seeing the physical evidence that this occurred."
Donald Grayson, a University of Washington anthropology professor who has studied the animal extinctions, also is skeptical.
Grayson said there are other explanations for the black mats, which
"are most assuredly not an indicator of an impact event." There's no
evidence of massive burning at the end of the last ice age, he said,
and there's no evidence suggesting that "post-Clovis human densities in
North America were less than Clovis ones."
Comment: This is clearly untrue, given the evidence presented in
href="http://www.sott.net/image/image/tmp/1192199131.712848.21225/Firestone_YD-impact2007.pdf" target="_blank">the article:
In the 1990s, W. Topping (14) discovered magnetic microspherules and
other possible ET evidence in sediment at the Gainey PaleoAmerican site
in Michigan (see also ref. 15), and Lougheed (16) and Bi (17) reported
that late Pleistocene glacial drift contained similar cosmic spherules.
We now report substantial additional data from multiple, well dated
stratigraphic sections across North America supporting a major ET
airburst or collision near 12.9 ka. Directly beneath the black mat,
where present, we found a thin, sedimentary layer (usually 5 cm)
containing high concentrations of magnetic microspherules and grains,
nanodiamonds, iridium (Ir) at above background levels, and fullerenes
containing ET helium. These indicators are associated with charcoal,
soot, carbon spherules, and glass-like carbon, all of which suggest
intense wildfires. Most of these markers are associated with previously
recorded impacts, but a few are atypical of impact events. We identify
this layer as the YD boundary (YDB), and we refer to this incident as
the YD event....
Ten Clovis and equivalent-age sites were selected because of their
long-established archeological and paleontological significance, and,
hence, most are well documented and dated by previous researchers (see
SI Table 2). Two are type-sites where unique PaleoAmerican projectile
point styles were first named: the Clovis-point style at Blackwater
Draw, NM, and the Gainey-point style at Gainey, MI. Three of the sites
are confirmed megafaunal kill sites, and six of 10 have a black mat
overlying the YDB. At Blackwater Draw and Murray Springs, the YDB is
found directly beneath the black mat and overlying Clovis artifacts
with extinct megafaunal remains.The other sample sites were in and around 15 Carolina Bays, a group
of 500,000 elliptical lakes, wetlands, and depressions that are up
to10 km long and located on the Atlantic Coastal Plain (SI Fig. 7). We
sampled these sites because Melton, Schriever (20), and Prouty (21)
proposed linking them to an ET impact in northern North America.
However, some Bay dates are reported to be 38 ka (22), older than the
proposed date for the YD event.
src="http://www.sott.net/image/image/4102/medium/06977Fig7.jpg" />
©PNAS
Fig.
7. Aerial photo (U.S. Geological Survey) of a cluster of elliptical and
often overlapping Carolina Bays with raised rims in Bladen County,
North Carolina. The Bays have been contrast-enhanced and selectively
darkened for greater clarity. The largest Bays are several kilometers
in length, and the overlapping cluster of them in the center is ≈8 km
long. Previous researchers have proposed that the Bays are
impact-related features.
It's interesting to note that the 38 Ka dates of some of the Carolina Bays correspond to two 19,000 year
precessional periods.
The skepticism is natural "given the magnitude of this hypothesis
and its potential significance in the history of our planet," and more
research is needed, Douglas Kennett said. "The scale of the inquiry is
also massive, and we have just started to scratch the surface "
Richard L. Hill: 503-221-8238; richardhill@news.oregonian.com
Comment: The fact that large scale cometary impacts have happened so relatively recently, and seem to
href="http://www.sott.net/articles/show/128992-Forget-About-Global-Warming-We-re-One-Step-From-Extinction-" target="_blank">happen in
cycles, and are getting so much attention lately, makes one wonder if
href="http://www.sott.net/articles/show/142651-Something-Wicked-This-Way-Comes" target="_blank">Something Wicked This Way
Comes.
Right now, NASA is tracking 127 asteroids that have a very small
chance of striking the planet. That number is about to get a lot
higher. Stronger telescopes, and a new mandate from Congress, will
allow scientists to detect thousands of smaller asteroids more likely
to hit Earth. And scientists are plotting ways to stop them, from
"gravity tractors" to solar ray guns. "There is no question that these
will hit the Earth," says Russell Schweickart, a former Apollo
astronaut who is involved in a group studying asteroids. "The question
is how often we will have to do something about it." In fact, Schweickart thinks world leaders might have to do something about it very
soon, within the next 15 years.
Stronger telescopes or more asteroids
and comets?
And what would cause these cycles?
Cometary evidence of a massive body in the outer Oort cloud
Approximately 25% of the 82 new class I Oort cloud comets have an
anomalous distribution of orbital elements that can best be understood
if there exists a bound perturber in the outer Oort cloud.
Statistically significant correlated anomalies include aphelia
directions, energies, perihelion distances and signatures of the
angular momentum change due to the Galaxy. The perturber, acting in
concert with the galactic tide, causes these comets to enter the loss
cylinder - an interval of Oort cloud comet perihelion distances in the
planetary region which is emptied by interactions with Saturn and
Jupiter. More concisely, the impulse serves to smear the loss cylinder
boundary inward along the track of the perturber. Thus it is easier for
the galactic tide to make these comets observable. A smaller number of
comets are directly injected by the impulsive mechanism. We estimate
that the perturber-comet interactions take place at a mean istance of
25000 AU. The putative brown dwarf would have a mass of 3 +/- 2M
Jupiter and an orbit whose normal direction is within 5 degrees of the
galactic midplane. This object would not have been detected in the IRAS
database, but will be detectable in the next generation of planet/brown
dwarf searches, including SIRTF. It is also possible that its radio
emissions would make it distinguishable in sensitive radio telescopes
such as the VLA.
The paper can be read here. Figures and tables are
here.
Jon Nance
The Springfield News-Leader
Thu, 01 Nov 2007 09:20 EDT
The first literate humans, living in Mesopotamian cities like Ur and
Erech more than 5,000 years ago, seemed to believe that comets caused
bad things to happen or, at the very least, they foretold that bad
things would happen. Either way, they regarded a new comet in the
evening sky as a portent of some future disaster.
If they were right, then the time has come for us to don sackcloth
and ashes, because a new comet appeared last week in the constellation
Perseus.
Well, almost.
The "new" comet turns out to be a familiar one with a period of 6.9
years, now about 100 million miles from Earth. It was discovered by
British amateur astronomer Edwin Holmes in 1896 and, according to
custom, given his name.
Comet Holmes was, until last week, a tiny ball of dusty ice only a
couple of miles in diameter, held together by electrochemical forces as
much as by gravity. Its gritty surface reflected just enough sunlight
to make it shine at 17th magnitude, far beyond the reach of unaided
human eyes. It then brightened abruptly to magnitude 2.5 and became the
third-brightest object in Perseus, brighter than all but two of the
constellation's stars.
It remains about that bright as I write this.
It is clearly visible even to my feeble eyes and is a rather large and quite unstarlike fuzzy blob when viewed with binoculars.
Try finding it about 7:40 tonight. It will be about halfway down
from the "W"-shaped asterism of Cassiopeia to the northeastern horizon
and a little to the left of Mirfak, Perseus' brightest star. If you
have trouble using this description, try consulting the finder chart at
the Web site of Sky and Telescope Magazine, www.skyandtelescope.com.
How did comet Holmes manage to increase its brightness almost a
millionfold in only a few days? Some kind of explosion seems to have
blown a large quantity of dust and grit from its surface out into the
surrounding space.
Moving outward at more than 1,000 miles per hour, this dust now occupies a volume nearly equal to that of the sun.
But what caused the explosion? Not many astronomers seem willing
even to guess about that in print right now. So we can be pretty sure
that no one knows.
Jon Nance is professor emeritus at Missouri State University.
Glenn K. Roberts
The Guardian
Thu, 01 Nov 2007 15:44 EDT
Though the nights are definitely chillier now, there's much to see
in the night sky worth getting out for, especially this month.
Dress warmly and head for a dark site away from city lights and
enjoy the special treats on display for those with the fortitude to
venture forth.
The show starts just after sunset, with Jupiter shining brightly low
in the southwest sky. You'll have to be quick to spot Jupiter's four
largest moons - Io, Europa, Callisto and Ganymede - as Jupiter will
follow the sun below the horizon soon after darkness falls. On Nov. 12,
look for the slender, three-day old crescent moon just to the lower
left of Jupiter.
Mars is preparing for its best showing in the past two years next
month by nearly doubling in brightness and increasing significantly in
apparent size in November. Mars is heading towards opposition in
December, when it will be at its brightest and peak visibility.
It begins November in a slightly gibbous phase, but by month's end,
its disk will be nearly full. Look for Mars rising in the east about
three hours after sunset in the constellation of Gemini - the Twins. If
you have a telescope, begin observing just before midnight, watching
for subtle dark and bright markings. Make a note of your observations,
perhaps even making a coloured sketch, so that you can compare your
observations with those in December.
As November opens, Saturn struts onto the night's celestial stage in
the east around 2 a.m. By month's end, it will rise shortly before
midnight. Always a spectacular sight in a telescope, Saturn's ring
system is worth looking for. If your telescope is a decent size and has
good optics, you might catch a glimpse of Saturn's brightest moon -
Titan - north of the planet on Nov. 3 and 19, and south of the planet
on Nov. 11 and 27.
Bright Venus returns to the early morning sky this month, rising an
hour and a half after Saturn appears above the eastern horizon and four
hours before the sun. An excellent photo opportunity is in the pre-dawn
sky of Nov. 4, when the crescent moon sits between Saturn and Venus.
The next morning, the moon will sit to the right of Venus.
Mercury makes its best showing of the year this month, reaching its
highest point in the east-southeast sky (approximately a hand's width
at arm's length) about 45 minutes before sunrise on Nov. 8. The solar
system's innermost planet rises about 90 minutes before the sun.
On Nov. 7, look for the crescent moon to the right of Mercury, with
bright Spica (the brightest star in the constellation of Virgo - the
Maiden) just below. If you've never seen Mercury, try and see it this
month as by month's end it disappears from view.
The second of the year's two premiere meteors showers - the Leonids
(radiant in Leo - the Lion) - arrives this month, peaking in the
pre-dawn sky of Nov. 18. Although it is expected that the peak, which
arrives about 3 a.m. on Nov. 18 when the Leo is high in the eastern
sky, will generate 20-40 meteors/hour, in the Maritimes we may be
treated to increased numbers of meteors just before midnight on Nov. 17
when Earth crosses the orbital node of the Leonids' parent comet,
Temple-Tuttle. Dress warmly, get comfortable with a chair or lots of
blankets, get out early and get ready for the show. It just might be
one of those rare times when we will be treated to a meteor storm.
In the hours just preceding dawn, when the Leonids strike Earth's
atmosphere almost head on, expect to see some very bright meteors and
perhaps even some fireballs, streaking across the sky.
Even as the stars fade and the eastern horizon starts to glow, keep
watching, as fireballs can easily be seen through the twilight.
Two comets can be found in the November night sky. Soon after the
sun has set and twilight deepens, use binoculars or a telescope to scan
just above the southwest horizon. Comet LONEOS should be visible just
above the horizon, with its tail angling up towards Jupiter. A decent
telescope should show the comet's two tails - the bright, yellowish,
dust tail curving towards the north and the duller, bluish, ion tail
streaking straight out from the comet's southeastern flank. Be quick to
see this visitor to the solar system as after the first week of
November, the comet will be all but impossible to see in binoculars or
small telescopes.
The other comet now in the sky is something of a pleasant surprise.
Just last week, in the latter days of October, Comet Holmes (discovered
in 1892 by British astronomer, Edwin Holmes) suddenly blossomed from an
extremely faint comet (visible in only the largest of telescopes) to
naked-eye visibility, a million-fold increase in brightness. It now
sits in the constellation of Perseus - the Warrior Prince in the
northeast sky as darkness falls. It is clearly visible to the naked-eye
as a bright, fuzzy ball which, as has just been reported, has swollen
in size to an object larger than Jupiter (at an equal distance). Go to
SpaceWeather.com for more information, pictures and a sky chart on this
amazing comet and get outside the first clear night available and have
a look at Comet Holmes.
Until next month, clear skies and good hunting.
Events (ADT):
Nov. 1 - Last quarter moon; 6:18 p.m.
Nov. 9 - Moon at apogee (farthest from Earth; 404,310 kms); 8:32 a.m.
Nov. 9 - New Moon; 7:03 p.m.
Nov. 17 - First Quarter Moon; 6:33 p.m.
Nov. 17 - Leonid meteor shower (start looking before midnight)
18 - Leonid meteor shower peak (around 3 a.m.)
Nov. 23 - Moon at perigee (closest to Earth; 355,120 kms); 8:13 p.m.
Nov. 24 - Full moon; 10:30 a.m.
Glenn K. Roberts, a member of the Charlottetown Astronomy Club, writes for The Guardian the first Thursday of the month.
To comment on his column e-mail him at groberts @isn.net.
BBC News
Fri, 02 Nov 2007 15:51 EDT
A Devon astronomer was able to track the unexpected brightness of a comet with a telescope in the Canary Islands.
 src="http://www.sott.net/image/image/4138/medium/comet_holmes.jpg" /> |
| ©n/a |
| The earth in relation to the comet is 244 million km (151 614 570 miles) away |
Professor Tim Naylor from Exeter University saw Holmes Comet using the Isaac Newton Telescope at La Palma.
Professor Naylor said: "Comets are not normally my thing, so it was
a challenge to observe something so bright with a large telescope."
The comet has brightened by a factor of a million and can now be seen across the UK with the naked eye.
Fuzzy object
On Monday the comet was a very faint object that needed a
large telescope to see it, then on Tuesday night, Professor Naylor saw
it suddenly become much brighter.
The comet is seen as a small fuzzy object as bright as a
medium-brightness star in the constellation Perseus and can be viewed
for the next few weeks.
Back in Exeter the professor said: "I walk out in to my back garden and my eight year old can see it.
"The best time is early evening before the moon comes up."
Astronomers believe a build-up of gas under part of the surface has
ruptured it making it appear brighter but they are still studying it to
find out the cause.
Dawn Stover
popsci.com
Tue, 30 Oct 2007 18:02 EDT
 src="http://www.sott.net/image/image/4140/medium/asteroid_lander.jpg" /> |
| ©Nick Kaloterakis |
| On the Rocks: Deep-space travelers arrive at their destination. Lack of gravity could make exploring the asteroid tricky. |
A manned mission to an asteroid sounds far-fetched, but a new
study says it will soon be possible. The goal?: "to significantly alter
the orbit of an asteroid, in a controlled manner, by 2015."
Here we are, nearly eight years into the 21st century, and the most
spectacular manned mission NASA can pull off is a trip to the
International Space Station, a mere 210 miles above the Earth. Even the
most ambitious part of NASA's current plans for human spaceflight
involves visiting a celestial body we've already been to: the moon.
Astronauts, space buffs and an unimpressed public hunger for space
exploration that's more dramatic, more heroic, more new. Something
like, say, landing astronauts on a distant rock hurtling through space
at 15 miles per second.
That's exactly the kind of trip NASA has been studying. In fact,
scientists at the space agency recently determined that a manned
mission to a near-Earth asteroid would be possible using technology
being developed today. The mission wouldn't be easy. A crew of two or
three would spend months riding in a cramped spacecraft before reaching
their barren, nearly gravity-free target. That such a mission is even
being considered, though, says a lot about the versatility of NASA's
next fleet of spacecraft and the ambitions the agency has for them. If
nothing else, it's a signal that space exploration could soon get much
more exciting.
The Allure of an Asteroid
This wouldn't be our first trip to an asteroid. We've been visiting
them by proxy for years now, using unmanned space probes. In 2000
NASA's NEAR Shoemaker spacecraft arrived at 433 Eros, which a century
earlier became the first near-Earth asteroid known to man; five years
later, the Japanese Hayabusa probe touched down on asteroid 25143
Itokawa.
Yet unmanned probes have their limitations. NEAR Shoemaker and
Hayabusa gathered a good deal of data, but we still don't know the
exact composition and internal structure of the asteroids they visited.
And although Hayabusa was designed to collect two small samples from
Itokawa, it's doubtful the probe will actually have anything onboard
when it returns in 2010.
Humans, however, could be much more effective. Unlike robots, we
adapt to our environment in real time. "We spend weeks at a rock with a
Mars rover, trying to determine what it is," says Rob Landis, an
engineer at NASA's Johnson Space Center and one of the co-leaders of
the mission feasibility study. "An astronaut could make that
determination in a matter of seconds."
A human crew could travel across an asteroid more intelligently than
a robot, making it easier to deploy scientific instruments, collect
samples, and zero in on the areas of greatest interest. "No doubt, on a
human mission we would characterize an asteroid better than we ever
have," says Bruce Betts, director of projects for the Planetary Society.
Plenty of characterization needs to be done. While most asteroids
are a safe distance from Earth (in an approximately
190-million-mile-wide expanse between Mars and Jupiter), Jupiter's
gravitational tug and, less often, collisions between asteroids can
kick these objects into orbits that pass uncomfortably close to Earth. The
270-meter-wide asteroid 99942 Apophis, for example, will pass within
roughly 24,000 miles of Earth in 2029, and could come back for a direct
hit in 2036.
And if we're to have any hope of deflecting asteroids, we need to
know a lot more about them than we do now. First off: What, exactly,
are they made of? Measurements taken by Hayabusa indicate that 40
percent of Itokawa's volume is empty space. If some asteroids are truly
this porous, that's helpful information for any plan to destroy or
deflect an Earth-bound object.
Averting the apocalypse isn't the only reason to study near-Earth
asteroids, though. They could be floating gold mines for future
deep-space expeditions. Preliminary observations suggest that some
asteroids are rich in useful minerals and, better yet, frozen water -
the most valuable resource a space traveler could hope to find. If
water could be extracted from asteroids, it could not only be used for
drinking, but also broken down into oxygen for breathing and hydrogen
for rocket fuel. "It might be an ultimate way to get to Mars," Landis
says.
Far beyond the Moon
Forty-one years ago, a scientist at Northrop (now Northrop Grumman)
proposed using moon rockets to go to an asteroid. In some ways, NASA's
latest plan is similar; it too relies on spacecraft designed for lunar
travel - the vehicles belonging to the Constellation program, which
NASA is building to replace the shuttle and then go to the moon and
beyond.
But although the hardware is similar, an asteroid mission couldn't
be more different from a trip to the moon. Actually, an asteroid
mission has one clear advantage: The virtually negligible gravity at
the crew's destination means they need less fuel to get home.
That lack of gravity, however, means that the first person to reach
an asteroid will not take one giant leap for mankind, and he will not
drive a dune buggy. "You're going to be wearing a backpack and flying
around," says Rusty Schweickart, an Apollo 9 astronaut who is
now chairman of the B612 Foundation, whose goal is "to significantly
alter the orbit of an asteroid, in a controlled manner, by 2015."
Astronauts might explore the asteroid from inside their spacecraft
using remotely controlled instruments, or they might anchor their
spacecraft to the surface of the asteroid by firing hooks into the
object and reeling themselves in.
The biggest logistical hurdle is the sheer distance involved. It
takes a few days to travel the 238,855 miles to the moon, but it will
take more than a month to cover the distance of up to 4.5 million miles
separating us from just about any asteroid of interest. The crew of two
or three will live in their small quarters for several months.
Psychological experiments and historical precedent show that isolation
and boredom can mentally break an otherwise sane person; NASA will have
to find a way to keep an asteroid-bound crew from losing their minds.
It will also have to engineer a means to shelter the astronauts from
the intense cosmic radiation found outside the protection of Earth's
magnetic field.
Most ominously, though, there's this little wrinkle: If anything
goes wrong out there for an asteroid-bound space traveler, there's
almost no chance of rescue.
Destination: Unknown
Which asteroids would we visit? "You need an asteroid that's in an
orbit very similar to the orbit of the Earth," says David Morrison, a
senior scientist at the NASA Astrobiology Institute. "There aren't
many, so we would be quite dependent on carrying out a new survey." The
ideal target asteroid will also be at least a couple hundred meters in
diameter, will have a very slow rotation of 10 hours or more, and will
have the potential to come too close to Earth for comfort. Scientists
suspect approximately 1,000 asteroids meet these criteria - but we have
yet to find them.
In 2005, Congress ordered NASA to develop a program to detect,
track, catalog, and characterize, by the end of 2020, 90 percent of all
near-Earth objects (an expanded category that includes comets as well
as asteroids) 140 meters in diameter and larger. The hitch: Right now,
NASA doesn't have the budget to get it done by that deadline.
The interplay between Congress and NASA brings up the more
terrestrial matter of politics. The stated goal of President George
Bush's administration is to launch an "extended" moon mission by 2020
and, later, to build a permanent moon base that could function as a
springboard for a manned mission to Mars. That could all change after
next year's election, however. A new administration could divert money
from human space exploration to any number of other projects - say,
satellite-based climate science. "I don't think that the Vision" - the
Bush administration's plan for a new era of human space exploration -
"as written today is likely to survive the election, even if a
Republican is elected," says Robert Zubrin, president of the Mars
Society.
Then again, some experts believe the Constellation program will move
forward no matter who wins in '08; if it doesn't, NASA won't have any
spacecraft after the shuttle retires. And although the feasibility
study doesn't mean we're headed to an asteroid soon, it does tell us
that if we decide to go, we can get there. So if, say, we find one day
that we need to visit 99942 Apophis to find the best way to knock it
off a collision course with Earth, or if we need a refueling station
for astronauts headed for Mars, we might be in luck.
Comment: To add another possibility for NASA's growing interest in near earth asteroids, be sure to see the SOTT Focus
Feature: Something Wicked
This Way Comes
Associated Press
Mon, 05 Nov 2007 20:43 EST
 border="0" src="http://www.sott.net/image/image/4220/medium/3a5d795283f6e88595042f9bde65a647.jpg" /> |
| ©Unknown |
| Comet Holmes is seen among the stars of the constellation Perseus in the North-Eastern sky. |
KNOXVILLE, Tenn. - A comet that unexpectedly brightened in the last
couple of weeks and is now visible to the naked eye is attracting
professional and amateur interest.
Paul Lewis, director of astronomy outreach at the University of
Tennessee, is drawing students to the roof of the Nielsen Physics
Building for special viewings of Comet 17P/Holmes.
The comet is exploding and its coma, a cloud of gas and dust
illuminated by the sun, has grown to be bigger than the planet Jupiter.
The comet lacks the tail usually associated with such celestial bodies
but can be seen in the northern sky, in the constellation Perseus, as a
fuzzy spot of light about as bright as the stars in the Big Dipper.
"This is truly a celestial surprise," Lewis said. "Absolutely amazing."
Until Oct. 23, the comet had been visible to modern astronomers only
with a telescope, but that night it suddenly erupted and expanded.
A similar burst in 1892 led to the comet's discovery by Edwin Holmes.
"This is a once-in-a-lifetime event to witness, along the lines of
when Comet Shoemaker-Levy 9 smashed into Jupiter back in 1994," Lewis
said.
Scientists speculate the comet has exploded because there are
sinkholes in its nucleus, giving it a honeycomb-like structure. The
collapse exposed comet ice to the sun, which transformed the ice into
gas.
"What comets do when they are near the sun is very unpredictable,"
Lewis said. "We expect to see a coma cloud and a tail, but this is more
like an explosion, and we are seeing the bubble of gas and dust as it
expands away from the center of the blast."
Experts aren't sure how long the comet's show will last but estimate
it could be weeks if not months. Using a telescope or binoculars help
bring the comet's details into view, they said.
New Scientist
Tue, 06 Nov 2007 11:13 EST
Comet 17P/Holmes has certainly given sky-watchers - backyard and
professional astronomers alike - a thrilling chance to see a cometary
outburst on a grand scale. After we posted my story
about on-going speculation about what could have caused this outburst
(and the one 115 years ago), many readers posted comments related to
two questions: Could this have been triggered by a collision with
an object in the main asteroid belt? And why can't we see more of a
tail on this comet?
 src="http://www.sott.net/image/image/4251/medium/holmes.jpg" /> |
| ©Pic du Midi Observatory/Francois Colas/Jean Lecacheux/Boris Baillard |
| Holmes |
Here's what I found out: Michael Mumma
at the Goddard Center for Astrobiology says such a collision in the
asteroid belt is theoretically conceivable. He noted that comet guru
target="_blank">Fred Whipple suggested
that a collision with a small asteroid could have provided the right
amount of energy to produce the ejecta and brightening observed in the
comet's 1892 flare-up.
But Mumma himself thinks it would be "very surprising" if a
collision were the cause of the outburst. He says part of the
difficulty in weighing this possibility is that it's very hard to
estimate how many small boulders are in the asteroid belt. These tiny
objects - on the order of one-metre across - are beyond the detection
limits of telescopes.
Brian Marsden, former director of the International
Astronomical Union's Minor Planet Center,
says plainly that he doesn't believe this to be a viable explanation
for the outburst. He says it's hard to believe that this comet, among
all those that pass through the asteroid belt, has been struck twice by
objects in the belt - once in 1892 and again this year.
Many people have been discussing whether or not this comet has a tail. Comets typically have
href="http://www.windows.ucar.edu/tour/link=/comets/tail.html&edu=high" target="_blank">two types of tail
- a dust tail and an ion tail. The dust tail is made of fine dust from
the comet's main body, or nucleus, that has been swept out by the Sun's
radiation. It usually points in the direction from which the comet
came. The ion tail is caused by the Sun's magnetic field sweeping ions
(which start out as neutral gas particles on the body of the comet)
into a line that always points directly away from the Sun.
Marsden says the there isn't much of either type of tail. He says
it's possible that there just isn't enough very fine dust in the
material coming off the nucleus to be pushed by sunlight into a nice
dust tail. (He says there may only be "fairly hefty dust" in the
comet's coma.)
Some people have argued that we can't see the comet's ion tail
because the orientation of the Sun, Earth and comet means the tail is
mostly pointing away from Earth.
But though the tail does look fore-shortened, Mumma says the
accumulated surface brightness would be greater seen from one end than
if it were seen spread out, from the side. He likened it to looking at
the contrail of a plane. If we saw the stream from the side, we would
basically see right through it. But if we were in front of or behind
the contrail, looking into it, it would appear many times brighter.
Marsden says the comet is so far from the Sun that the solar wind is
not interacting strongly enough with the ionised gas to produce a
fantastic ion tail. But he says it doesn't bother him that it doesn't
have much of a tail. After all, the "fuzzy head" is putting on such a
great show of its own.
Kimm Groshong, contributor
Maria Cristina Valsecchi
National Geographic
Thu, 08 Nov 2007 06:06 EST
Almost a century after a mysterious explosion in Russia flattened a
huge swath of Siberian forest, scientists have found what they believe
is a crater made by the cosmic object that made the blast.
The crater was discovered under a lake near the Podkamennaya
Tunguska River in western Siberia, where the cataclysm, known as the
Tunguska event, took place.
 src="http://www.sott.net/image/image/1826/medium/070626_cheko_sonar2_02.jpg" /> |
| ©www-th.bo.infn.it/tunguska / University of Bologna |
| A three-dimensional rendering of Lake Cheko in Tunguska, Siberia. The level of the lake is lowered 40 meters (131 feet) to emphasize its cone-like shape. |
On June 30, 1908, a ball of fire exploded about 6 miles (10
kilometers) above the ground in the sparsely populated region,
scientists say. The blast released 15 megatons of energy - about a
thousand times that of the atomic bomb dropped on Hiroshima - and
flattened 770 square miles (2,000 square kilometers) of forest.
 src="http://www.sott.net/image/image/1334/medium/tunguska.jpg" /> |
| ©unk |
| The Tunguska event devastated parts of Siberia in 1908 |
Since then many teams of scientists have combed the site, but none
was able to find any fragments of an object, like a rocky asteroid or a
comet, that might have caused the event.
In their new study, a team of Italian scientists used acoustic
imagery to investigate the bottom of Lake Cheko, about five miles
(eight kilometers) north of the explosion's suspected epicenter.
"When our expedition [was at] Tunguska, we didn't have a clue that
Lake Cheko might fill a crater," said Luca Gasperini, a geologist with
the Marine Science Institute in Bologna who led the study.
"We searched its bottom looking for extraterrestrial particles
trapped in the mud. We mapped the basin and took samples. As we
examined the data, we couldn't believe what they were suggesting.
"The funnel-like shape of the basin and samples from its sedimentary
deposits suggest that the lake fills an impact crater," Gasperini said.
A "Soft Crash"
The basin of Lake Cheko is not circular, deep, and steep like a typical impact crater, the scientists say.
Instead it's elongated and shallow, about 1,640 feet (500 meters) long with a maximum depth of only 165 feet (50 meters).
It also lacks the rim of debris usually found around typical impact craters, such as the Meteor Crater in Arizona.
Gasperini's team says that the basin's unusual shape is the result
of a fragment thrown from the Tunguska explosion that plowed into the
ground, leaving a long, trenchlike depression.
"We suggest that a 10-meter-wide [33-foot-wide] fragment of the
object escaped the explosion and kept going in the same direction. It
was relatively slow, about 1 kilometer a second [0.6 mile a second],"
Gasperini said.
The lake is located along the most probable track of the cosmic
body, he added, which likely made a "soft crash" in the marshy terrain.
"It splashed on the soft, swampy soil and melted the underlying
permafrost layer, releasing CO2 [carbon dioxide], water vapor, and
methane that broadened the hole, hence the shape and size of the basin,
unusual for an impact crater.
"Our hypothesis is the only one that accounts for the funnel-like morphology of Lake Cheko's bottom," he added.
In a previous expedition, Russian scientists studied Lake Cheko and
concluded that it had formed before 1908, indicating that it was not
formed by the Tunguska event.
The team had measured sediments on the bottom of the lake and
determined that the deposits were accumulating there at about 0.4 inch
(1 centimeter) a year. This suggested that Lake Cheko was several
centuries old.
But Gasperini's team argues that the older deposits found by the Russians were already there when the explosion took place.
"We found evidence that only the topmost, one-meter-deep
[three-foot-deep] layer of debris actually came from the inflowing
river," Gasperini said.
"[The] deeper sediments are deposits that predate 1908. They were
the target over which the impact took place, so Lake Cheko is only one
century old."
The team's findings are based on a 1999 expedition to Tunguska and appeared in the August issue of the journal Terra Nova.
Asteroid or Comet?
William Hartmann, senior scientist of the Planetary Science
Institute in Tucson, Arizona, said the new findings are compelling but
do not address all of the lingering questions about the event.
"It's an exciting result that might shed new light on the Tunguska
explosion," he said. "Certainly it warrants new studies of the area.
"But it raises a question in my mind: If one large fragment hit the
ground, we would normally expect thousands of smaller fragments also to
hit the ground along the path, and many searches have failed to find
such meteorite fragments. So, why no smaller pieces?"
Finding fragments from the explosion is considered key to
determining what kind of object made the impact. An asteroid would
probably leave some remains, while a comet might be annihilated in the
blast, Hartmann said.
"Our crater hypothesis is consistent with both possibilities," Gasperini said.
"If the body was an asteroid, a surviving fragment may be buried
beneath the lake. If it was a comet, its chemical signature should be
found in the deepest layers of sediments."
Gasperini and his colleagues are planning to go back to Siberia next
year to search for more, and perhaps more conclusive, clues to the
century-old puzzle.
"We want to dig deeply in the bottom of the lake to definitively
test our hypothesis and try to solve the Tunguska mystery," he stated.
href="http://www.carrollcountytimes.com/articles/2007/11/10/features/in_focus/columns/curtis_roelle/star993.txt">Leonid meteor shower could
pack a punch
Curtis Roelle
carrollcountytimes.com
Sat, 10 Nov 2007 00:34 EST
November's annual Leonid meteor shower is associated with debris
left behind during passages of Comet 55P/Tempel-Tuttle. Although this
year's shower is expected to be unremarkable, there is a chance that
short-lived outbursts could occur.
The 2007 shower may be unremarkable but it is notable for several
reasons. First, it is expected to peak on a weekend night, making it
easier for observers who like staying up late. The nominal predicted
peak should occur on the night of Nov. 17 to Nov. 18.
Second, the moon gets out of the way before things get going.
According to Sky & Telescope magazine, the best viewing "starts
around midnight, when Leo rises." In Westminster, the moon cooperates,
setting at 12:53 Sunday morning. The magazine says you will "likely see
the most meteors 2-3 hours before sunrise."
The best way to increase the number of meteors you can expect to see
during any shower is to observe from a dark sky site far away from
interference from artificial outdoor lighting. This means traveling
away from any nearby cities. The darker the sky is at your observing
site the more meteors you will see.
Third, depending on which model you subscribe to, one or more
outbursts may happen in which the expected hourly meteor rate spikes
briefly. In his "Astronomical Calendar 2007," Guy Ottewell writes of a
predicted outburst with a "zenithal hourly rate" (ZHR) of up to 200
meteors per hour between 11 p.m. Saturday and midnight.
Another outburst prediction is based on a model derived by Esko
Lyytinen and Tom van Flandern. It was used to successfully predict an
outburst in the 2006 Leonid shower. In a recent e-mail message to
StarPoints, Mr. Lyytinen of Finland noted that he expects this outburst
"to be quite weak" consisting primarily of "faint meteors" and fewer in
number than last year's modest outburst of "only a few dozens" of
meteors.
The underlying cause is that the Earth is expected to travel through
debris left by Tempel-Tuttle during its 1932 passage. Unfortunately,
this outburst is predicted to occur around 6 p.m. Nov. 18. Thus it
won't be well suited for viewing from the United States.
Another outburst prediction by Russian Mikhail Maslov is based on a
modified version of the Lyytinen-van Flandern model. It expects the
surge to have a ZHR up to 60 to 65 meteors per hour.
The ZHR is an idealized rate with a technical meaning. It is the
number of meteors that may be expected in one hour if the "radiant" -
the point in the sky from which all meteors in a given shower appear to
emanate from - was located at the observer's zenith (straight overhead)
and viewed from a dark sky site free from light pollution. Of course,
the radiant won't be that high in the sky, so the actual rate will be
lower.
SpaceWeather.com
Sat, 10 Nov 2007 00:40 EST
"Is Comet 17P/Holmes losing its tail?" asks Italian astronomer
Paolo Berardi. "Last night I recorded an image showing a big
disconnection event that was not present on Nov 8th."
 src="http://www.sott.net/image/image/4323/medium/comet_holmes.jpg" /> |
| ©Paolo Berardi |
Jack Newton of the Arizona Sky Village saw it, too. "The comet has a
huge eruption moving along its tail. Holmes is more bizarre with each
passing day."
This event does not necessarily signal a new outburst of Comet
Holmes. Comet tails can be disconnected by gusts of solar wind which
trigger magnetic storms around the comet akin to geomagnetic storms
which fuel auroras on Earth.
BBC News
Sat, 10 Nov 2007 08:35 EST
A supposed asteroid, which it was feared was going to have a
near-miss with Earth next week, has been identified as a spacecraft.
 src="http://www.sott.net/image/image/4349/medium/Rosetta.jpg" /> |
| ©ESA |
| The unmanned Rosetta craft has already flown past Earth once |
Professor Alan Fitzsimmons of Queen's University Astrophysics
Research Centre told the BBC there is "no longer any need for concern".
"The 'asteroid' has been identified as the European spacecraft Rosetta," he said.
The spacecr
aft is en route to a comet near Jupiter.
Earlier this year, the unmanned Rosetta craft, which has already
flown past Earth once, passed within 250 km (150 miles) of Mars.
In a precise move, the probe used the planet's gravity to change course on its voyage to the Churyumov-Gerasimenko comet.
Helen Altonn
Star Bulletin
Sun, 11 Nov 2007 17:13 EST
 src="http://www.sott.net/image/image/4357/medium/art4a.jpg" /> |
| ©University of Hawaii |
| A comparison of Comet Holmes, the sun and Saturn (inset) is shown in this image from the University of Hawaii. |
Once a faint, obscure comet, 17P/Holmes has eclipsed the sun as the
largest object in the solar system and it's still growing, Hawaii
astronomers say.
The spectacular comet has dazzled astronomers since it exploded Oct.
24 from a tiny nucleus of ice and rock about 2.2 miles in diameter.
On Friday, the mass of ejected dust was measured at 900,000 miles
across by Rachel Stevenson, Pedro Lacerda and Jan Kleyna of the
University of Hawaii Institute for Astronomy.
They used observations from the Canada-France-Hawaii Telescope on
Mauna Kea, which has a wide-field camera capable of capturing the whole
comet in one image, the astronomers said.
Also participating in the research were astronomy professor David
Jewitt, researcher Nuno Peixinho and graduate student Bin Yang.
People can see the comet as a fuzzy object with the unaided eye but it's much better with binoculars, Jewitt said.
The comet is expanding at about 1,100 mph and is "an unprecedented
million times brighter" than before its outburst, UH astronomers said.
The comet's nucleus appears as a white "star" near the center of the
cloud of dust on the image. A tail also is starting to grow, the
scientists reported.
Jewitt said about 10 million tons of dust erupted from the comet.
"It's like something broke on the nucleus and all this stuff poured out into space," he said.
The comet was discovered in an outburst in November 1892, then faded
and burst again in January 1893, he said. Both outbursts were almost
the same size, Jewitt said, explaining they probably occurred when the
comet was at its closest to the sun and were triggered by the sun's
heat.
The IFA team will continue observations from Mauna Kea in case the
comet follows the same pattern as it did more than 100 years ago, he
said. "The comet is well placed in the sky for a long time so we'll be
able to follow it from Mauna Kea for many, many months."
Comet Holmes, with an orbit period of about six years, is in a class
of "Jupiter Family Comets" with orbits influenced strongly by Jupiter,
the astronomers said.
It's believed these objects orbited the sun beyond Neptune in the
Kuiper Belt region for most of the last 4.5 billion years, they said.
In a few thousand years, the astronomers said the comet is likely to
either hit the sun or a planet, be ejected from the solar system, or
simply run out of gas and disappear.
 src="http://www.sott.net/image/image/4358/medium/art4b.jpg" /> |
| ©Sky and Telescope |
CQ Congressional Testimony
Thu, 08 Nov 2007 08:51 EST
Statement of Donald K. Yeomans Manager, NEO Program Office Jet Propulsion Laboratory
Committee on House Science and Technology Subcommittee on Space and Aeronautics
Mr. Chairman and members of the Subcommittee, thank you for the
opportunity to appear today to discuss the potential threats of
near-Earth objects (NEOs), our progress toward meeting the discovery
goal articulated in the NASA Authorization Act of 2005, the role of the
Arecibo planetary radar within the NEO program and the response options
available if a NEO is found to be on an Earth impacting trajectory.
The Near-Earth Object Population: When
the Earth was young, frequent collisions of comets and asteroids likely
delivered much of the water and carbon-based molecules that allowed
life to form, and once life did form, subsequent collisions may have
punctuated the evolutionary process and allowed only the most adaptable
species to progress further. We may owe our very existence atop the
world's food chain to these objects. As the Earth's closest neighbors
(some pass within the moon's distance), these icy comets and rocky
asteroids have been termed near-Earth objects. Their proximity to Earth
presents an opportunity to utilize their vast metal, mineral and water
ice resources for future space structures and habitats. Their water
resources can be broken down into hydrogen and oxygen - the most
efficient form of rocket fuel. These near-Earth objects may one day be
the resources, fueling stations and watering holes for human
interplanetary exploration. While these objects are of extraordinary
scientific interest, likely enabled the origin of life itself, and may
loom large for the future development of space exploration, their
proximity to Earth also presents a potential horrific threat should a
relatively large near-Earth object once again strike Earth without
warning. Potentially Hazardous Asteroids: Near-Earth objects are comets
and asteroids that can pass within 45 million kilometers of the Earth's
orbit. While some showy, naked-eye comets may occasionally pass close
to Earth, it is the difficult to find (but far more numerous asteroids)
that are of most concern in near-Earth space today. About one fifth of
the near-Earth asteroids can approach the Earth's orbit even closer (to
within 7.5 million kilometers), and these so-called potentially
hazardous asteroids (PHAs) are of most concern for near-term hazard
avoidance.
Celestial debris hits the Earth all the time, but the vast majority
of it is so small that it does not survive passage through the Earth's
atmosphere. The debris is created over millions of years, as asteroids
inevitably run into each other, producing smaller fragments, which
themselves collide yielding even more debris. Over time, the fragments
and debris spread out, and some of it migrates into Earth approaching
orbits. The Earth is pummeled with more than 100 tons of impacting
material each day but almost all of it is far too small to cause
anything other than a harmless meteor, or shooting star, or the
occasional fireball event. Larger objects are less numerous than
smaller objects and hit the Earth less often. While a basketball-sized
object strikes the Earth's atmosphere daily, larger car-sized impactors
hit only a few times each year, and even these generally break up into
smaller pieces as they streak through the atmosphere. Occasionally a
fragment of a larger impactor will reach the Earth's surface -- one
such hit may have occurred less than two months ago when a reported
asteroid fragment perhaps one meter in diameter struck in southern Peru
creating a 13-meter crater near Lake Titicaca.
Larger impactors with diameters in the 50 to 140 meter range, while
they do not usually impact the ground, can result in damaging air
blasts that cause significant destruction. For example, on June 30,
1908, an impactor with a diameter of about 50 meters detonated over the
Tunguska region of Siberia and leveled trees for 2000 square
kilometers. Its impact energy has been estimated at about 10 million
tons of TNT explosives (10 megatons or 10 MT), comparable in energy
with a modern nuclear weapon. Roughly speaking, PHAs that have
diameters larger than 140 m can punch through the Earth's atmosphere
and cause regional damage if they strike land or create a harmful
tsunami should they impact into an ocean. There are thought to be about
20,000 PHAs in this size range, each with a potential impact energy of
100 MT or more. On average, one of these objects would be
expected to strike Earth every 5000 years and therefore would have a 1%
probability of impact in the next 50 years. Although their
mean impact frequency would be about once every 500,000 years, PHAs
larger than a kilometer in diameter could cause global consequences due
to not only the extraordinary blast itself (50,000 MT) but also the
dust and debris thrown into the air, and the subsequent firestorms and
acid rain. The extinction of the dinosaurs and a sizable fraction of
the Earth's other species some 65 million years ago is thought to be
due to an impactor with a diameter of about 10 kilometers that created
an impact energy of as much as 50 million MT. Over very long time
intervals, PHAs with diameters greater than one kilometer are
statistically the most dangerous objects because their impacts would
cause global consequences.
NASA Responses to the PHA Issues: In
1998, before the Subcommittee on Space and Aeronautics, a NASA
representative outlined the goal to discover and catalog 90% of the
NEOs larger than one kilometer by the end of 2008. There are currently
thought to be over 900 of these objects, and about 80% of them have
already been found and cataloged. Roughly the same percentage of PHAs
in this size range has also been found. When this goal has been
reached, 90% of the global risk from PHAs would be retired. Almost all
of these discoveries have come by way of NASA supported search programs.
As part of the NASA Authorization Act of 2005, NASA was asked to
consider options for extending the search down to objects as small as
140 meters in diameter, and to find and catalog them within 15 years of
the Act becoming law (i.e., by the end of 2020). By finding and
cataloging 90% of this population of PHAs, the statistical or actuarial
risk to Earth from PHAs of all sizes would be reduced by 99% from
pre-survey levels. We can speak of risk reduction in this case because
once an object is discovered and cataloged, its future motion can
accurately be predicted and, in the unlikely case where it does
threaten Earth, there would be sufficient time to deflect it, thus
saving the enormous costs due to fatalities and/or infrastructure
damage. According to a 2003 NASA NEO Science Definition Team study that
undertook a cost/benefit analysis for the discovery of PHAs, the risk
reduction accruing from this next generation PHA search would pay for
itself in the first year of operations. While an impact by a 140
meter-sized object would not generate global physical consequences, its
impact energy would still be about 100 MT, and the likelihood of one of
these impacts is 100 times greater than an impact by one of the less
numerous one kilometer-sized PHAs. With regard to the uncertainty
associated with threats from PHAs, the largest factor, by far, is the
large number of undiscovered objects in the size ranges that are small
enough to be very numerous but large enough to easily penetrate the
Earth's atmosphere. For example, we have discovered only about 4% of
the 20,000 PHAs larger than 140 meters and less than 1% of the 200,000
objects larger than 50 meters. The solution to this uncertainty is to
continue and hopefully accelerate the search for PHAs. Once we find the
vast majority of them, they can be tracked, cataloged and then ruled
out (or in) as threats during the next 100 years or so. This process
can continue year after year so the window of safety is always at least
100 years. There are other, less significant, uncertainties dealing
with the refinement of a particular object's size, mass and structure
as well as the dynamical model that is used to accurately predict the
object's motion over 100 year time scales. For example, over long time
intervals, the minute pressure of sunlight and its thermal re-radiation
can significantly affect a PHA's motion. For a select number of Earth
approaching objects, we will need the use of the planetary radars, or
possibly rendezvous spacecraft missions, to better understand their
sizes, shapes, masses, surface properties, and possible binary natures.
The Next Generation of Search: As
noted, the current NASA NEO goal is focused upon the discovery and
tracking of objects one kilometer in diameter and larger. It is not
realistic to expect the current survey program, with its modestly sized
telescopes, to efficiently find the 140 meter-sized objects that are
nearly 50 times fainter compared to a one kilometer-sized object at the
same distance and with the same reflectivity. Because all PHAs do
eventually come very close to the Earth, the current ongoing surveys
could complete the goal outlined in the 2005 NASA Authorization Act but
it would likely take over a century to do so. We cannot afford to wait
that long.
In the report to Congress requested by the 2005 NASA Authorization
Act, several options were outlined, both ground- based and space-based,
that could meet the goal of finding 90% of the PHAs larger than 140
meters by the end of 2020. For example, a one-meter aperture infrared
telescope in a heliocentric orbit near Venus could do the job three
years early. Within this report, NASA noted that it did not have the
resources to carry out a survey option that would meet the 2020
deadline set by the 2005 Act and that, in an attempt to achieve the
legislative goal by the end of 2020, it would seek to continue the
current survey programs and look for opportunities to use dual use
telescope facilities and spacecraft along with partnering with other
agencies as feasible.
At least two next-generation, ground-based, wide-field search
telescope surveys are in development. The Panoramic Survey Telescope
and Rapid Response System (PanSTARRS), under development at the
University of Hawaii with Air Force funding, will have one of its four
1.8 meter telescopes operational in Hawaii in early 2008. If the
planned, four telescope version of PanSTARRS is completed by 2010, it
could help reach the goal by about 2040. Likewise the 8.4 meter
aperture Large Synoptic Survey Telescope (LSST) that is under
development with funding from NSF, DoE and other partners, could help
reach the goal by about 2034 if it began operation in 2014. If we
assume that both the PanSTARRS four telescope system and the LSST
operate in their planned shared modes, which includes many observations
unrelated to PHAs, then the goal could be reached by about 2026. The
PHA discovery rate could be increased beyond the results shown in the
NASA response to the 2005 Act if the observing time and sequences of
PanSTARRS and LSST were optimized for PHA observations.
In terms of actual discoveries of new PHAs, there has been little
success beyond the survey programs supported by NASA. However, the
international community, including many sophisticated amateur
astronomers, is very active in providing the follow-up observations
necessary to secure an object's orbit once it has been found. The
NEODyS program in Pisa Italy works closely with, but independent of,
the NEO Program Office at JPL to compute impact probabilities for
predicted Earth close approaches for at least 100 years into the
future. It is also encouraging to note the activities of a NEO Action
Team within the UN Committee on the Peaceful Uses of Outer Space
(COPUOS) includes an effort to encourage more international efforts on
the NEO issues.
The importance of Radar Observations:
There are only two planetary radars in existence (and no alternatives)
that can routinely observe close Earth approaching asteroids, and both
of them are critically important for investigating the nature of these
objects and for rapidly refining their trajectories. The 70- meter
Goldstone antenna in California's Mojave desert is fully steerable, can
track an asteroid and can cover large regions of sky while the larger
305-meter Arecibo antenna in Puerto Rico has twice the range but only
observes within a 40-degree zone centered on the overhead position (20
degrees on either side of zenith). The capabilities of these two
telescope complement one another and often a significantly better and
longer set of observations can be achieved using both radars on a close
approaching target asteroid.
Most positional data for PHA orbit determination and trajectory
predictions are based upon optical, plane-of-sky observations. Because
the radars provide line-of-sight velocity and range information
accurate to about the 1 mm/s and 10 meter levels, these data when used
in conjunction with the optical data provide a secure orbit and
trajectory far more rapidly than if only optical data are available.
With only a limited amount of optical data to work with, the orbit of a
newly discovered PHA is often not accurate enough to immediately rule
out a future Earth impact. However, with radar data in hand, the orbit
of a newly discovered PHA can be quickly and more precisely determined,
its motion accurately projected far into the future and future impact
possibilities can usually be quickly ruled out. Likewise, in the rare
situation when an object is actually on an Earth threatening
trajectory, radar observations will be critical in quickly identifying
this case.
Unfortunately the Arecibo radar program is not funded by the NSF
beyond FY2007 and the planetary science community is in danger of
losing one of its instrumental crown jewels. As a measure of this radar
facility's importance, note that 65% of all radar experiments to
characterize near-Earth asteroids were performed at Arecibo, 47% of all
binary near-Earth asteroids were discovered at Arecibo and 85% of the
near-Earth asteroids with the critical astrometric radar data for orbit
improvement have data from Arecibo. All of this was accomplished with
only 5% of this instrument's time. The superior sensitivity of the
giant Arecibo radar can determine the sizes, shapes, rotation
characteristics, surface characteristics and binary nature for many
PHAs. All of these physical characteristics are important criteria to
understand before a deflection mission is considered. Radar
observations are responsible for the best physical characterization of
any PHA as large as a kilometer (i.e., the binary asteroid 1999 KW4).
Radar observations reduce a PHA's orbit uncertainties quickly and
dramatically so that future impact possibilities can be quickly knocked
down thus reducing the odds that we will need to invest in a spacecraft
investigation to characterize the PHA's nature in preparation for a
precautionary deflection mission. Thus the relatively modest costs of
maintaining the Arecibo radar in a robust state could prevent the
future need for 100's of millions of dollars per case for spacecraft
reconnaissance of an object to determine whether or not it is an actual
threat.
What Should be Done in the Event of an identified NEO Threat?
A number of existing technologies can deflect an Earth threatening
asteroid - if there is time. The primary goal of the PHA survey
programs is to discover them early and provide the necessary time. An
asteroid that is predicted to hit Earth might require a change in its
velocity of only 3 millimeters per second if this impulse were applied
twenty years in advance of the impact. The key to a successful
deflection is having sufficient time to carry it out, whether it is the
slow, gentle drag of a gravity tractor or a more impulsive shove from
an impacting spacecraft or explosive device. In either case, a
verification process would be required to ensure the deflection
maneuver was successful and to ensure the object's subsequent motion
would not put it on yet another Earth impacting trajectory. While
suitable deflection technologies exist, none of them can be effective
if we are taken by surprise. It is the aggressive survey efforts and
robust planetary radars that must ensure that the vast majority of
potentially hazardous objects are discovered and tracked well in
advance of any Earth threatening encounters. The first three steps in
any asteroid mitigation process are: Find them early, find them early,
and find them early!
Lee Pullen
Astrobio.net
Mon, 12 Nov 2007 20:45 EST
Jupiter is known as many things: king of the planets, an impressive
gas giant, defender of the inner solar system. This last notion comes
from the idea that Jupiter is so massive that its gravitational
influence deflects objects like comets, which, as they spiral toward
the Sun, could potentially hit inner planets such as the Earth.
 src="http://www.sott.net/image/image/4403/medium/aog.jpg" /> |
| ©Unknown |
| Comet impacts pose a serious threat to life on Earth. |
Without Jupiter acting as a "cosmic vacuum cleaner" sucking up these
dangerous objects, there would be so many catastrophic impacts that
life probably wouldn't have evolved on the Earth and we wouldn't be
here today. At least, this is the commonly accepted wisdom. Like so
many topics in astrobiology, it isn't as straightforward as it first
seems. Jonti Horner and a team from the UK's Open University have been
addressing the question of whether Jupiter is our friend or foe.
"This vacuum cleaner idea goes back to when the long-period comets
coming in from the Oort Cloud were viewed as being the only significant
impact risk," says Horner. "In the 1950s there were only one or two
near-Earth asteroids known, so they were viewed as oddities."
Astronomers in the 1950s realised that comets were approaching the
solar system from extreme distances - so far away that the Sun,
Jupiter, and other planets were essentially a single point-source of
gravitational influence. When the comets got close enough to resolve
the Sun and Jupiter as separate objects, they then had different forces
pulling at them, resulting in a change of direction.
"The comets get a very slight kick, an increase in energy, from
Jupiter," says Horner. "For these comets, Jupiter stops them from
coming back time and time again; Jupiter makes them leave. The great
majority of long-period comets only come through once but they have a
very small chance of hitting the Earth."
 src="http://www.sott.net/image/image/4404/medium/aoh.jpg" /> |
| ©Unknown |
| Jupiter can act as a shield, soaking up impacts as happened in 1994 with comet Shoemaker-Levy 9. |
Since the 1950s, scientists have discovered more objects in the
solar system, and they say many of them could collide with us. The
objects are found primarily in the asteroid belt between Mars and
Jupiter, but a few remnants from the planet formation era 4.6 billion
years ago are dotted around the solar system. Horner believes it's
these two groups of asteroids - and not comets - that are most
dangerous to life on Earth.
"Occasionally there are collisions between these objects, and when
they collide they get nudged onto different orbits and into unstable
regions," says Horner. "Then Jupiter can start to perturb them and
nudge them around. That's where we get the near-Earth asteroids from,
and these are now perceived to be the greatest risk to our planet."
But just how common are these impacts? Do they occur often enough to
endanger life? Horner and many other scientists believe so. Part of the
danger depends on the size of the object. It's been estimated that
about 75 million meteors hit the Earth every day, but because they are
typically no bigger than a grain of sand, they'll just leave a pretty
trail in the night sky. It's not these tiny meteors that concern
Horner, it's their larger relatives that inhabit the solar system.
"The bigger they are, the less frequent the impacts are, but the
more interesting they become, and certainly more threatening," says
Horner. "A figure that's banded around is that a one kilometer-sized
object would hit the Earth on average every 300,000 years. A one
kilometer object is the threshold between being a locally-damaging
event and a globally-damaging event. Bigger than this, and you get a
lot of people falling over."
It's not just the size or frequency of impacts that has to be taken
into consideration. Speed also is an important factor. Doubling the
velocity can put four times more energy into the impact.
"The long-period comets are more of a threat at a given size because
they hit harder and faster," says Horner. "With the near-Earth
asteroids, you'd need a bigger object hitting us to have the same
amount of devastation."
Horner and his team reasoned that for a planet to be habitable over
appreciable periods of time, it would have to somehow avoid impacts of
extinction-level size and speed. However, smaller and slower impacts
also may stop life from developing if they hit regularly enough.
 src="http://www.sott.net/image/image/4405/medium/aoj.jpg" /> |
| ©Unknown |
| Horner's graph simulates impact rates on the Earth over a ten million year timescale. Changing the mass of Jupiter has a dramatic effect. |
Despite the apocalyptic potential of asteroids and comets, Horner's
research suggests we're more likely to find habitable worlds elsewhere
in the galaxy. He says that the presence of a gas giant planet isn't as
important as everyone thinks, and that means there is greater wiggle
room in our definition of what makes a solar system habitable. He also
theorises that impacts may not always be detrimental to life -- in
fact, they may be essential.
"It may be that if you have too few impacts, life will stagnate," he
says. "It may even be that our Earth is not the ideal in terms of
intelligent life evolving. Maybe we have too few impacts, which is why
it's taken us four and a half billion years to get here."
However, until life is found elsewhere scientists can only guess at
what environmental conditions are best for intelligent life to evolve
and persist. In the meantime, Horner's results may cause us to alter
our ideas of where life could form, and the conditions under which it
can develop. The next step in his research is to look at the effect of
smaller planets, such as Neptune. Could it be that they have more of an
influence on our own world than we currently believe? Horner also hopes
to use complex computer simulations to move Jupiter into different
orbits, experimenting with how the distance of a gas giant from a
habitable world affects impact rates. Jupiter may well have more
surprises in store.
icRenfrewshire.co.uk
Mon, 12 Nov 2007 09:30 EST
Stargazers will be in seventh heaven when one of the most spectacular sights in the night sky becomes visible above Paisley.
And, to make the outlook even brighter, Buddies won't even need binoculars or telescopes to identify the celestial wanderer.
They'll see it all with the naked eye.
 src="http://www.sott.net/image/image/4418/medium/Comet+Holmes+Finder_l.jpg" /> |
| ©Sky and Telescope |
Comet Holmes, first discovered in 1892 by English amateur astronomer
Edwin Holmes, has now come back into view during its seven-year orbit
around the Sun.
And, during the next few weeks, it will be seen as a yellow-coloured
star surrounded by a hazy cloud in the constellation Perseus, which
begins its nightly journey in the north-east sky - that's in the
Glasgow direction.
One man who'll have his head in the clouds while it's all happening
will be top astronomer John Pressly, information officer at Coats
Observatory in Paisley.
"What makes Comet Holmes unusual is that it literally brightened
overnight, from a very faint object detectable only with a powerful
telescope to an object visible to the naked eye," said Mr Pressly. "The
comet has just become one million times brighter than it had been, most
likely because of explosions within it.
"These explosions ejected a massive cloud of dust surrounding the
centre. This dust cloud reflects sunlight, which is why we can see it
so easily.
"A comet is like a dirty snowball, composed of dust and gas, which
periodically orbits around our sun. Comets are believed to be the
leftovers from the time that the planets formed and could even contain
clues to the origins of life on our planet.
"The centre of the comet is known as the nucleus. As the comet nears
the sun, it will start to melt, giving off dust and gas, which usually
forms in a tail at the back of the comet, pointing away from the Sun."
Mr Pressly added: "Comet Holmes can be seen in the constellation of
Perseus, which rises in the early evening and which should be high
enough in the sky by 8pm for people to be able to find the comet.
"The easiest way to find it is to look for the distinctive W shape
of the constellation Cassiopeia, high in the north-eastern sky. Perseus
lies just below Cassiopeia.
"Comet Holmes looks different than the surrounding stars, shining
with a constant, yellowish colour as opposed to the bluish twinkling
light of the surrounding stars.
"At present, Comet Holmes is some 150 million miles from Earth and should stay at this distance as it orbits the Sun.
"The comet is visible to the naked eye, even with the heavily light polluted skies of Paisley.
"Through binoculars, it looks like a circular hazy cloud, very different from the background stars.
"In our telescope at the observatory, the nucleus should be visible
as a faint point of light surrounded by a cloud of bright dust."
Buddies who want to see the comet at close quarters are being invited along to the observatory in Oakshaw Street West.
They'll get the chance when Mr Pressly and his colleagues at the
observatory train their large telescope on the cosmic comet to allow
visitors a chance to see for themselves the rare sky marvel.
The observatory will be open to the public on Tuesday and Thursday
nights from 6.30pm to 9.30pm, with last admission at 9pm. Entry is free
and there is no need to book. Viewing is only possible on clear
windless evenings.
Physorg.com
Mon, 12 Nov 2007 09:40 EST
 src="http://www.sott.net/image/image/4419/medium/asteroid_impact.jpg" /> |
| ©NASA |
| Artist's concept of a catastrophic asteroid impact |
Hollywood thrillers such as Deep Impact helped to
jump-start America's interest in knowing what our "deflection strategy"
would be if a giant asteroid was on a potentially catastrophic
collision course with Earth.
Chris Palma, senior lecturer in astronomy and astrophysics at Penn
State, says that such events are statistically highly probable.
"Throughout Earth's history, we have been bombarded by comets and
asteroids from space," Palma notes. "Impacts happened more frequently
in the past, but they will happen again. It is just a matter of when."
Explains Palma, a law was passed two years ago requiring NASA to "to
both survey for near Earth objects and come up with a plan to divert
those objects." Yet, some experts have criticized both NASA
and the United States government for not doing enough to prevent
potential impacts with Earth.
The so-called Tunguska event in 1908, believed to have been the only
large-scale meteorite hit within recorded human history, reportedly
flattened over 830 square miles of Siberia, with an explosion a
thousand times more powerful than the atomic bomb dropped on Hiroshima.
While it is staggering to imagine such damage in a heavily populated
area, Palma cautions that "we have no experience with these scenarios
and can't do more than estimate the number of lives that will be lost
and the amount of damage to the infrastructure in the impact region."
Programs have been set into place to help predict and monitor
threats posed by meteorite and asteroid impacts, such as NASA's Near
Earth Object Program and University of Arizona's SpaceWatch group.
However, Palma's impression is that the majority of similarly focused programs are spearheaded by "individual
researchers."
What would happen if an asteroid was detected heading toward Earth?
A number of different ideas have been proposed, says Palma, including
"sending a very massive unmanned spacecraft towards the asteroid and
using the ship's gravitational pull to nudge the asteroid off course."
Adds Palma, the idea isn't to physically push it, but rather to use the
spacecraft's strong gravitational pull to cause the asteroid to move
into a different orbit without directly impacting the asteroid."
Would such a dramatic, heroic endeavor succeed? "My guess," says
Palma," is that this particular model is a good theoretical starting
point, but not one that is necessarily going to be feasible if applied."
Is enough being done to prepare for potential threats? As with so
much else, it all depends on who you ask, though all agree that the
stakes are high. After all, the most popular explanation for dinosaur
extinction is the widespread after-effects of a giant asteroid impact.
Regarding our current state of deflection readiness, Palma says, "I
think it is a bit of a stretch to say that NASA is doing nothing about
this, but at the same time, I think you can argue that they should be doing more."
thunderbolts.info
Tue, 13 Nov 2007 22:44 EST
Spacecraft have now visited four comets. What they found contradicts
what was expected and falsifies accepted comet theory. But that theory
is woven with every other astronomical theory into a cosmology that
defines the universe as we know it. The fall of comet theory will
inevitably bring us a new and different universe.
 src="http://www.sott.net/image/image/4448/medium/050923comets.jpg" /> |
| ©NASA/JPL/Malin Space Science Systems |
| Comet Wild 2 is shown in close-up above. Beside it is a microscopic view of an EDM (electrical discharge machined) surface. Note the flat-floored depressions with steep scalloped walls and terracing. The small white spots on the comet can then be reasonably identified as the active cathode arcs that produce the cometary jets. |
Comets are giving accepted comet theory a hard time. Close-up images
of comet nuclei from spacecraft have contradicted about every
expectation of theory. ("Expectation" is a euphemism for "prediction";
a disappointed expectation is practically the same thing as a failed
prediction, except with the former you don't expect you'll have to
discard the theory.) "If astronomy were a science," as one astronomer
put it, theoreticians would admit that the theory had been falsified,
and they would start over with an eye to the evidence. Instead, they
hang on to the theory with ever more stubbornness and hope a little
tinkering and adjusting will bring the facts into line.
The facts are apt to be more stubborn than the theoreticians: Deep
Impact kicked up ten times more dust than expected and stimulated the
comet's activity a magnitude less than expected. The dust was not a
conglomeration of sizes as expected but was consistently powder-fine.
The nucleus of the comet was covered with sharply delineated features,
two of which were circular enough to be called impact craters. This was
not expected for a dirty snowball or a snowy dirtball or even a powdery
fluffball.
The craters, of course, weren't actually called impact craters. They
must have been caused by subsurface explosions, because they had flat
floors and terraced walls, despite the myriad of other craters on rocky
planets and moons with flat floors and terraced walls that are called
impact craters. All the other circular depressions with flat floors and
terraced walls weren't craters because they had "unusual shapes."
The hard times began with Comet Halley. Theory expected more or less
uniform sublimation of the surface as the nucleus rotated in the sun,
much as you would expect of a scoop of ice cream on a rotisserie. But
Halley had jets. Less than 15% of the surface was sublimating, and the
ejecta was shooting away in thin beams.
The theory was adjusted to introduce hot spots, chambers below the
surface in which pressure could build up and erupt through small holes
to produce the jets. It went unmentioned that the holes must have been
finely machined, like the nozzle of a rocket engine, in order to
produce the collimation of the jets: Just any rough hole would result
in a wide spray of gases.
Borrelly made the hard times harder. It was dry. And black.
Theoreticians tinkered with the dirty snowball theory until they got
the dirt to cover the outside and to hide the snow inside. Somehow they
got the dirt, which ordinarily is an insulator, to conduct heat
preferentially into the rocket chambers to keep the jets going.
Wild 2 defied them. Its jets were not just around the sub-solar
point, where the Sun's heat would be greatest. This comet sported jets
on the night side. The rocket chambers now had to store heat for half a
"comet day". And something was needed to keep the jets coherent over
great distances and to gather their emissions into a stream of clumps:
Clusters of particles repeatedly struck the spacecraft.
Comet theorists announced that comets were mysteries and that the
theorists knew nothing, that they had to "think differently". Then they
proposed adjustments to the accepted theory that would be acceptable to
the accepted way of thinking.
Different theories abound - but outside the walls of astronomical
acceptability. For an astronomer to recognize their existence would be
to jeopardize his position and salary. But the characteristics of
comets that are so difficult to explain with snowballs are fairly easy
to explain with electricity.
Electrical theories
date back to the 1800s, before "electricity" became taboo in astronomy.
They were well-founded on observations and on the proven laws of
electromagnetism. In the last few decades, they have been refined to
the point where they expected the findings that were so
hard on the fashionable theory:
Comets are electrical discharges in the thin plasma that permeates
the solar system. Because they spend most of their time far from the
Sun, their rocky nuclei are in equilibrium with the voltage at that
distance. But as they accelerate in toward the Sun, their voltage is
increasingly out of equilibrium with the voltage and increasing density
of the solar plasma. A plasma sheath forms around them - the coma and
tail. And filamentary currents - jets - between the sheath and the
nucleus erode, particle by powdery particle, the circular depressions
with terraced walls that are typical of electrical discharge machining.
As the discharge channels move across the surface of the comet, they
burn it black.
If it were only a matter of explaining with plasma discharges the
jets and the blackened rocky surfaces and the powder-fine dust and the
terraced depressions, there might not be so much blinkered
stubbornness. But modern astronomical theories have been worked into an
interlocking web of explanation. Each theory supports, and is in turn
supported by, nearly every other theory. If one theory frays, if one
loose thread is pulled, the entire fabric will unravel.
An electrified comet requires an electrified Sun.
The Sun is the focus of the electric field that causes the comet to
discharge. For the Sun to maintain its electric field, it (and all
stars) must be the focus of another electric discharge within an
target="_blank">electrified galaxy. And electrified galaxies, with their magnetic fields and x-ray emissions and ejections of quasars, must be
connected in larger circuits that render
meaningless such fancies of cosmology as the Big Bang theory.
If you pull one electrified comet out of the well-knit structure of
accepted theories, the entire garment will become unacceptable. Either
the universe is an agglomeration of isolated, gravitating,
non-electrical bodies, or else it is a network of bodies connected by
and interacting through electrical circuits. Either the universe is a
gravity universe or it is an Electric Universe.
And comets are the loose thread.
David Jewitt
University of Hawaii
Thu, 15 Nov 2007 04:04 EST
Formerly, the Sun was the largest object in the Solar System. Now, comet 17P/Holmes holds that distinction.
Spectacular outbursting comet 17P/Holmes exploded in size and brightness on October 24. It continues to expand and is now the
largest single object in the Solar system, being bigger than the Sun (see Figure).
The diameter of the tenuous dust atmosphere of the comet was
measured at 1.4 million kilometers (0.9 million miles) on 2007 November
9 by Rachel Stevenson, Jan Kleyna and Pedro Lacerda of the University
of Hawaii Institute for Astronomy.
They used observations from a wide-field camera on the
Canada-France-Hawaii Telescope (CFHT), one of the few professional
instruments still capable of capturing the whole comet in one image.
Other astronomers involved in the UH program to study the comet include
Bin Yang, Nuno Peixinho and David Jewitt.
The present eruption of comet Holmes was first reported on October
24 and has continued at a steady 0.5 km/sec (1100 mph) ever since. The
comet is an unprecedented half a million times brighter than before the
eruption began. This amazing eruption of the comet is produced by dust
ejected from a tiny solid nucleus made of ice and rock, only 3.6 km
(roughly 2.2 miles) in diameter.
 src="http://www.sott.net/image/image/4497/medium/holmes_jewitt_071109.jpg" /> |
| ©Sun and Saturn images courtesy of NASA's SOHO and Voyager projects |
| (Left) Image of comet Holmes from the 3.6-meter Canada-France-Hawaii telescope on Mauna Kea showing the 1.4 million km diameter coma. The white ''star'' near the center of the coma is in fact the dust-shrouded nucleus. (Right) the Sun and planet Saturn shown at the same scale for comparison. |
The new image also shows the growth of a tail on comet Holmes (the
fuzzy region to the lower right in the comet picture), caused by the
pressure of sunlight acting on dust grains in the coma.
Over the next few weeks and months, the coma and tail are expected
to expand even more while the comet will fade as the dust disperses. Comet Holmes showed a double outburst in November 1892 and
January 1893.
It is not known if the present activity in the comet will follow the
pattern from 1892, but continued observations from Mauna Kea are
planned to watch for a second outburst. Most comets show small
fluctuations in brightness and some have distinct outbursts.
The huge event on-going in comet Holmes is unprecedented, however.
The orbit period of comet Holmes is about 6 years, putting it in the
class of Jupiter Family Comets whose orbits are strongly influenced by
Jupiter. These objects are thought to have spent most of the last 4.5
billion years orbiting the Sun beyond Neptune, in a region known as the
Kuiper Belt.
Holmes probably was deflected into its present orbit within the last
few thousand years and is losing mass as it evaporates in the heat of
the Sun.
In another few thousand years it is likely either to hit the Sun or
a planet, be ejected from the Solar system, or simply die by running
out of gas.
Contacts Rachel Stevenson [rach@ifa.hawaii.edu 808-956-6680] David Jewitt [jewitt@ifa.hawaii.edu 808-956-7682]
Comment: The same image is available from the University of Hawaii as a
href="http://www.ifa.hawaii.edu/faculty/jewitt/images/holmes_jewitt_071109.tif" target="_blank">300 dpi tif file.
Julie Steenhuysen
Reuters
Thu, 15 Nov 2007 23:10 EST
The normally sedate Comet Holmes made a bright splash in the sky
about two weeks ago, unexpectedly becoming a million times brighter
than normal overnight and causing a stir among astronomers.
 border="0" src="http://www.sott.net/image/image/4512/medium/Hubble_image_of_Comet_Holmes.jpg" /> |
| ©REUTERS/NASA, ESA, and H. Weaver/The Johns Hopkins University Applied Physics Laboratory/Handout |
| A Hubble image (R), taken November 4, 2007, shows the heart of Comet 17P/Holmes. The central portion of the image has been specially processed to highlight variations in the dust distribution near the nucleus. About twice as much dust lies along the east-west direction (the horizontal direction) as along the north-south direction (the vertical direction), giving the comet a "bow tie" appearance. The composite color image at left, taken on November 1, 2007, by an amateur astronomer shows the complex structure of the entire coma, consisting of concentric shells of dust and a faint tail emanating from the comet's right side. |
The comet and its expanding ball of dust have become the biggest
object in the solar system, with a diameter appearing even bigger than
the sun, according to astronomers at the University of Hawaii Institute
for Astronomy.
The fireworks began on October 23, when the comet brightened in a
24-hour period. It is now fading but can still be seen by the naked eye
in the northeastern sky.
"Something that spectacular is almost like a supernova going off,"
said Hal Weaver, a comet expert at The Johns Hopkins University Applied
Physics Laboratory.
"Now, we're trying to observe the event and figure out what the heck
happened," Weaver said in a telephone interview on Thursday.
Weaver and fellow astronomers, using the powerful Hubble telescope,
have some clues that may help explain the display. So far they have
noticed that the comet's nucleus, the small solid body that is the main
source of all the comet's activity, is still surrounded by dust.
He and colleagues believe some sort of explosion sheared off a
pancake-shaped slab of the comet, which crumbled into tiny dust
particles that are being lit up by the sun.
Hubble images of the comet from June 1999 showed no dusty halo. At
that time, they measured the comet's nucleus at some 2.1 miles, about
the length of New York City's Central Park.
DELAYED EFFECT
They are now hoping to examine the comet's size to see how much of it was sheared away in the blast.
Weaver said comets typically get most active when they are nearest
to the sun, but Comet Holmes, known officially as 17P/Holmes, made its
closest approach to the sun six months ago.
One reason he offered for the delayed effect was the presence of
volatile ice made up of carbon monoxide, dry ice, ethane, methane and
acetylene and hydrogen cyanide. These, he said, may have gotten heated
up but could not escape the comet's nucleus, causing a build-up of
pressure that eventually exploded.
Weaver also thinks there might be a seasonal effect, in which
different portions of the comet's nucleus are visible only at certain
points of the comet's orbit around the sun, which happens every seven
years.
Comet Holmes put on a similar display in 1892, which astronomers
believed was caused by a collision with another comet, which sliced off
a piece of Holmes' nucleus that slammed back into it again, sending up
a showy spray of dust.
"Now, we step forward to 2007, and the same thing is happening again. It indicates that hypothesis is incorrect," Weaver said.
While the magnitude of the light show is spectacular, he said comets do tend to flare up every now and then.
(Editing by Will Dunham and Xavier Briand)
Dr Derek Ward-Thompson
Cardiff University
Tue, 03 Feb 2004 17:46 EST
Scientists at Cardiff University, UK, believe they have discovered
the cause of crop failures and summer frosts some 1,500 years ago - a
comet colliding with Earth.
The team has been studying evidence from tree rings, which suggests
that the Earth underwent a series of very cold summers around 536-540
AD, indicating an effect rather like a nuclear winter.
The scientists in the School of Physics and Astronomy believe this
was caused by a comet hitting the earth and exploding in the upper
atmosphere. The debris from this giant explosion was such that it
enveloped the earth in soot and ash, blocking out the sunlight and
causing the very cold weather.
This effect is known as a plume and is similar to that which was seen when comet Shoemaker-Levy-9 hit Jupiter in 1995.
Historical references from this period - known as the Dark Ages -
are sparse, but what records there are, tell of crop failures and
summer frosts.
The work was carried out by two Cardiff undergraduate students, Emma
Rigby and Mel Symonds, as part of their student project work under the
supervision of Dr Derek Ward-Thompson.
Their findings are reported in the February issue of Astronomy and Geophysics, the in-house magazine of the Royal
Astronomical Society.
The surprising result of the new work is just how small a comet is
needed to cause such dramatic effects. The scientists calculate that a
comet not much more than half a kilometre across could cause a global
nuclear winter effect. This is significantly smaller than was
previously thought.
Dr. Ward-Thompson said: "One of the exciting aspects of this work is
that we have re-classified the size of comet that represents a global
threat. This work shows that even a comet of only half a kilometre in
size could have global consequences. Previously nothing less than a
kilometre across was counted as a global threat. If such an event
happened again today, then once again a large fraction of the earth's
population could face starvation."
The comet impact caused crop failures and wide-spread starvation
among the sixth century population. The timing coincides with the
Justinian Plague, widely believed to be the first appearance of the
Black Death in Europe. It is possible that the plague was so rampant
and took hold so quickly because the population was already weakened by
starvation.
There's A Mystery Object Not Far
From The Earth
New Scientist
Wed, 24 Feb 1999 15:14 EST
A chunk of rock some 50 metres across has
been found circling the Sun in an orbit close to Earth's. The object,
which was discovered on 10 February by an automated asteroid-hunting
telescope in New Mexico called Linear, is probably a chip off the Moon,
say astronomers.
After six nights of observations, Gareth Williams of the
Harvard-Smithsonian Center for Astrophysics in Cambridge,
Massachusetts, calculated that it circles the Sun every 1.09 years. Its
nearly circular orbit is just nine million kilometres farther from the
Sun than the Earth's.
The object's orbit is extremely unusual. Comets and
asteroids that cross the Earth's orbit normally have eccentric orbits.
There is only one asteroid-like object, called 1991 VG,
that has a similar orbit to that of the Earth. When it was discovered,
eight years ago, astronomers thought it might be a spacecraft that had
escaped the Earth's gravity.
The new object, designated 1999 CG9, is considerably brighter than
1991 VG, indicating that it is much larger. Brian Marsden of
Harvard-Smithsonian estimates it to be between 30 and 50 metres across,
too big to be the final stage of a rocket. "The most likely explanation
is that it's a chip off the Moon," he says.
Although the Moon is small, its low gravity makes it easy to blast
debris into orbit. "We have seen there are chips off the Moon," says
Marsden. "Twelve small lunar meteorites have been found on the Earth."
"If you can shoot things off the Moon, they would continue to go
around the Sun in an orbit not too different from the Moon," Marsden
adds. So far, astronomers do not know the object's composition, which
could cast light on its origins. However, the astronomers hope to
analyse the rock's spectrum to see how it compares with that of the
Moon.
href="http://www.borehamwoodtimes.co.uk/news/localnews/display.var.1837229.0.mystery_surrounds_great_balls_of_fire.php">Mystery
surrounds great balls of fire
Sara Dixon
Borehamwood and Elstree Times
Sat, 17 Nov 2007 17:19 EST
MYSTERY surrounds unidentified flaming objects which Borehamwood
residents claim to have spotted in the night sky in the past two months.
On September 6, Khristian Rawlings was shocked to see two large
balls of fire, the size and height of a large aeroplane, whizzing
across the sky as he stood on the balcony of his home in Howard Drive.
A month later, on November 5, Lisa Talbot saw a brightly burning
flying object, also travelling at the height of a plane, as she left a
fireworks display at the town's Meadow Park.
Father-of-one Mr Rawlings, 24, said: "They came across at around
9.15pm. They were orange, and the only way I could describe them is as
a bubble with a fireball in the middle. They were very bright, going at
some speed, and travelling towards London.
"They were very small at first and I thought they were a blip on my
glasses but they got bigger and I really thought something was amiss.
It was a bit creepy.
"I was scared to death. I told my girlfriend to get the baby, but she told me to calm down and not go crazy."
Mr Rawlings believes the peculiar sight could have been Russian spy planes or meteors.
Miss Talbot, 37, spotted the other mysterious object, also
travelling towards London, as she was returning to her Farriers Way
home with her nine-year-old daughter.
She said: "It was like a flame going though the sky and the ball was
turning around and around, glowing orange. The fireworks had finished
and it couldn't have been a firework, it was burning for too long.
Everybody stopped and stared at the object. It looked like a meteor.
"I immediately called my mother who had walked the opposite way to
me, up Shenley Road towards the old Holmshill School site. She too had
seen the object along with the crowd following her the same way.
Everybody was totally dumbfounded by what it could have been.
"I'll be keeping an eye out on December 5, to see if they come back."
A spokesman for Hertfordshire Constabulary said police had received no reports of unidentified flaming objects.
Mystery Event In Australian
Outback: Nuclear Blast, Earthquake Or Meteorite?
University of Colorado at Boulder
Wed, 28 May 1997 15:11 EDT
At the request of a U.S. Senate subcommittee on investigations, a
group of scientists has been analyzing a mysterious seismic event that
took place in a remote part of southwest Australia on May 28, 1993.
On that date, a group of aboriginal prospectors witnessed a radiant,
star-like object traveling low across the horizon followed by a bright
flash of light and a powerful explosion when the object disappeared
behind a ridge. The terrorist group responsible for the March 20, 1995
poison gas attack in a Tokyo subway had attempted to enrich uranium
near the epicenter of the mystery event, and Senate investigators
feared the group was conducting nuclear tests in the area.
Scientists examining the event are Christal B. Hennet and Gregory E.
van der Vink of Incorporated Research Institutions for Seismology in
New York, Danny Harvey of the University of Colorado at Boulder, and
Christopher Chyba of the University of Arizona. Harvey is a research
associate at the Joint Seismic Program Center in the CU-Boulder physics
department.
The researchers looked at factors such as location, depth and
magnitude to distinguish between possible causes of the event,
including an earthquake, a meteorite or an explosion. Their analysis
ruled out a nuclear explosion and suggests an iron meteorite more than
3 meters in diameter may have been the cause of the mysterious blast.
The group, which presented its findings at this week's meeting of
the American Geophysical Union in Baltimore on May 28, used seismic
data collected from various stations in Australia to analyze the event.
Such a meteorite would have left a crater more than 90 meters in
diameter, and the scientists are now attempting to define an area of
impact so that a ground search can be undertaken.
Anton Wylie
The Register
Sun, 18 Nov 2007 19:56 EST
But what's a Comet, anyway?
border="0" src="http://www.sott.net/image/image/4512/medium/Hubble_image_of_Comet_Holmes.jpg" /> |
| ©REUTERS/NASA, ESA, and H. Weaver/The Johns Hopkins University Applied Physics Laboratory/Handout |
| A Hubble image (R), taken November 4, 2007, shows the heart of Comet 17P/Holmes. The central portion of the image has been specially processed to highlight variations in the dust distribution near the nucleus. About twice as much dust lies along the east-west direction (the horizontal direction) as along the north-south direction (the vertical direction), giving the comet a "bow tie" appearance. The composite color image at left, taken on November 1, 2007, by an amateur astronomer shows the complex structure of the entire coma, consisting of concentric shells of dust and a faint tail emanating from the comet's right side. The normally sedate Comet Holmes made a bright splash in the sky about two weeks ago, unexpectedly becoming a million times brighter than normal overnight and causing a stir among astronomers. |
The Web is abuzz about Comet Holmes.
Comet 17P/Holmes had been expected to make just another routine
ultra low visibility departure from perihelion passage this year. But
in a record for a comet, it unexpectedly brightened by a factor of
around a million on October 24, making it more reminiscent of a stellar
nova explosion.
"Amateur astronomers the world over have been stunned and amazed by the weirdest new object to appear in the sky in memory,"
target="_blank" href="http://www.skyandtelescope.com/observing/home/10775326.html">wrote Sky and Telescope.
"The comet shocked skywatchers as it went from a dim 17th magnitude then suddenly to 3 magnitude"
href="http://www.skyscript.co.uk/forums/viewtopic.php?p=22353&sid=eb1cdddc7ad29f81a1f41da61a7aa2a3">wrote Theo from the
Pacific Northwest.(*)
Holmes brightened from below the threshold of binoculars to being
clearly visible with the unaided eye. The outburst presented as a
circular fuzzy patch in the constellation of Perseus, and has proceeded
to grow in size. The comet was then reported to have spawned a tail.
More drama was to come.
Spaceweather currently reports that "last Friday, astronomers
watched in amazement as the comet's tail broke off!".
And Comet Holmes may yet make further news, should this be a prelude
to the full-on fissioning of the comet's core into several pieces. The
comet is expected to remain visible to the naked eye for some weeks.
Why did Comet Holmes flare up?
Yet Comet Holmes has brightened up unexpectedly on a previous
occasion: that of November 1892 led to its discovery by E. Holmes in
England. It was subsequently determined to be a periodic comet, with a
revolutionary period of about every seven years. You can see its orbit
in relation to other planets courtesy of Larry's animation here.
Much less, though, has been made of the fact of where it was when
the current flare-up occurred. The Armagh Observatory's website puts
the comet at some 230m miles from the Sun - a distance from, and quite
a long time after, its closest point to the Sun, which occurred on May
4, 2007.
In the accepted view, comets are thought to comprise rocky and icy
solids in a mixture termed "rocky snowballs" by some and "icy
rockballs" by others. They get brighter and sprout tails as the "icy"
component is thought to sublimate from solid to gaseous state under the
influence of solar heating, which typically begins affecting them at a
point just inside the orbit of Jupiter. This gives rise initially to an
expanding light-reflecting aura known as the coma, which is then "blown
away" in the opposite direction from the sun by the solar "wind".
Multiple repeated thermally-induced mechanical stresses are thought
to give rise to a cometary aging process, whereby a large single core
disintegrates after multiple closer solar encounters into much smaller
fragments. When such orbiting debris intersects the Earth's orbit, it
can give rise to meteor showers.
Professionals, however, are well aware of exceptions.
Comet Wirtanen fragmented in 1957 when it was just inside the orbit
of Saturn. Conversely, in December 1680, the eponymous comet studied by
Halley and Newton passed intact within 100,000km of the Sun.
Things took a more serious turn, as reported in 1990 by New
Scientist.
The object named Chiron, discovered in 1977 as an asteroid orbiting
between Jupiter and Neptune, had begun to "look like a gigantic comet".
Forget for a moment the stuff comets are made of - here, the very categories of astronomy were under attack.
An ontological debate ensued, mostly in private, but recently
resulting in the public ejection of Pluto from the category of
"planet". In this debate, the retention of a solar system cosmogony -
including attachment to a primeval outer comet reservoir with links to
the present (the Oort Cloud) - has been a significant feature.
Why do comets split?
Yet as far back as 1989, Carl Sagan and Nancy Druyan had remarked on
the fact that 80 per cent of comets which split do so when they are far
from the Sun.
In their book Comet, they wrote:
The gravitational tides of the Sun or unequal heating cannot
be sole causes of the splitting of comets. We still do not know why
comets split.
Stranger still, Dr Brian Marsden, for many years astronomy's Mr Orbital Elements extraordinaire,
had noted in the 1960s that two comets, 1882 II and 1965 VIII, looked
as if they had split apart near aphelion (their farthest distance from
the Sun), beyond the orbit of Neptune and above the ecliptic plane. Has
nothing progressed?
Contemporary authorities such as David C. Jewitt of the Institute
for Astronomy, University of Hawaii, concede that still "most splitting
events occur without obvious provocation and their cause is unknown".
(See pdf, 1.2MB.)
This has not stopped cometologists devising ever more complex
structures for comets to account for the more evident facts: some
comets are conceived of as comprising an icy core well sealed in a
rocky shell; others as having a refractory mantle for their orbital
phase. But can the counter-intuitive nature of such theoretical
elaborations equal some of the more counter-intuitive facts which
recent observations have adduced, such as the production of X-rays?
Some commentators think that the
standard narrative of comets has been allowed to grow in an ad hoc manner for too long.
The Institute of Electrical and Electronics Engineers (IEEE) has for
many years had a Nuclear and Plasma Sciences Society subgroup, and has
published papers since 1986 on the application of plasmas to the
phenomena of astronomy. A 7th
series is underway.
Countering the astronomical consensus, plasma physicists account for
comet features in terms of a varying electrical potential experienced
by the comet as it changes location within the electrical plasma field.
This is the "solar wind" - centred on the Sun - which extends beyond
Pluto, and which is modified by the magnetic and electrical
contribution of the planets.
In this account, cometary comae and tails are the result of
electrical arcing, analogous to electrical discharge machining, rather
than sublimation.
The dual flashes of light observed when the Deep Impact spacecraft
mission despatched a copper impactor into Comet Temple 1 were
consistent with the expectations of plasma physicists. Scientists
observed two flashes: the second flash was due to the impact, but the
first flash was due to electrical discharge between the comet and the
impactor, and resulted in failure of the on-board data collection and
transmission systems.
A compilation of predictions about the Deep Impact encounter from the point of view of a plasma universe can be found
href="http://thunderbolts.info/tpod/2005/arch05/050704predictions.htm">here.
So a possible fragmentation of comet Holmes is not the only thing to
look forward to. Some are asking if God if not after all a crude
materialist, but a subtle electrician?
Follow the link above Larry's page for a comet-locating starmap. UK
readers should crane their necks round midnight to the zenith, and
adjust the gaze slightly north-east. With binoculars the fuzzy coma is
clearly visible. ®
(*) Bootnote
Unlike the rest of science, the "order" of stellar magnitude is
not computed to base 10, but to Pogson's Ratio of 2.512. To know
exactly why, you would need to build a time machine, travel back to the
ancient Greek period, and ask them how they could conceive of a sixth
rate star, when you or I might make do with third or fourth rate ones.
Comment: Enjoy our latest Forum's Topic:
Speculations about the Comet
17P/Holmes
NASA
Thu, 15 Nov 2007 00:00 EST
NASA's Hubble Space Telescope has probed the bright core of Comet
17P/Holmes, which, to the delight of sky watchers, mysteriously
brightened by nearly a millionfold in a 24-hour period beginning Oct.
23, 2007.
Astronomers used Hubble's powerful resolution to study Comet Holmes'
core for clues about how the comet brightened. The orbiting
observatory's Wide Field Planetary Camera 2 (WFPC2) monitored the comet
for several days, snapping images on Oct. 29, Oct. 31, and Nov. 4.
Hubble's crisp "eye" can see objects as small as 33 miles (54
kilometers) across, providing the sharpest most detailed view yet of
the source of the spectacular brightening.
The Hubble image at right, taken Nov. 4, shows the heart of the
comet. The central portion of the image has been specially processed to
highlight variations in the dust distribution near the nucleus. About
twice as much dust along lies along the east-west direction (the
horizontal direction) as along the north-south direction (the vertical
direction), giving the comet a "bow tie" appearance.
The composite color image at left, taken Nov. 1 by an amateur
astronomer, shows the complex structure of the entire coma, consisting
of concentric shells of dust and a faint tail emanating from the
comet's right side.
The nucleus-the small solid body that is the ultimate source of all
the comet's activity-is still swaddled in bright dust, even 12 days
after the spectacular outburst. "Most of what Hubble sees is sunlight
scattered from microscopic particles," explained Hal Weaver of The
Johns Hopkins University Applied Physics Laboratory in Laurel, Md., who
led the Hubble investigation. "But we may finally be starting to detect
the emergence of the nucleus itself in this final Hubble image."
Hubble first observed Comet 17P/Holmes on June 15, 1999, when there
was virtually no dusty shroud around the nucleus. From that
observation, astronomers deduced that the nucleus had a diameter of
approximately 2.1 miles (3.4 kilometers), about the length of New York
City's Central Park. Astronomers hope to use the new Hubble images to
determine the size of the comet's nucleus to see how much of it was
blasted away during the outburst.
Hubble's two earlier snapshots of Comet Holmes also showed some
interesting features. On Oct. 29, the telescope spied three "spurs" of
dust emanating from the nucleus, while the Hubble images taken on Oct.
31 revealed an outburst of dust just west of the nucleus.
The Hubble images, however, do not show any large fragments near the
nucleus of Comet Holmes, unlike the case of Comet
73P/Schwassmann-Wachmann 3 (SW3). In the spring of 2006 Hubble
observations revealed a multitude of "mini-comets" ejected by SW3 after
the comet increased dramatically in brightness.
Ground-based images of Comet Holmes show a large, spherically
symmetrical cloud of dust that is offset from the nucleus, suggesting
that a large fragment did break off and subsequently disintegrated into
tiny dust particles after moving away from the main nucleus.
Unfortunately, the huge amount of dust near the comet's nucleus and
the comet's relatively large distance from Earth (149 million miles, or
1.6 astronomical units, for Holmes versus 9 million, or 0.1
astronomical unit for SW3), make detecting fragments near Holmes nearly
impossible right now, unless the fragments are nearly as large as the
nucleus itself.
The Hubble Comet Holmes observing team comprises H. Weaver and C.
Lisse (The Johns Hopkins University Applied Physics Laboratory); P.
Lamy (Laboratoire d'Astrophysique de Marseille, France); I. Toth
(Konkoly Observatory, Hungary); M. Mutchler (Space Telescope Science
Institute); W. Reach (California Institute of Technology); and J.
Vaubaillon (California Institute of Technology).
The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency. The Space Telescope Science
Institute conducts Hubble science operations. The institute is operated
for NASA by the Association of Universities for Research in Astronomy,
Inc., Washington.
The Applied Physics Laboratory (APL) is a not-for-profit laboratory
and division of The Johns Hopkins University. APL conducts research and
development primarily for national security and for nondefense projects
of national and global significance. APL is located midway between
Baltimore and Washington, D.C., in Laurel, Md.
Scott Carney
Discover Magazine
Thu, 15 Nov 2007 07:44 EST
The serpent's tails coil together menacingly. A horn juts sharply
from its head. The creature looks as if it might be swimming through a
sea of stars. Or is it making its way up a sheer basalt cliff? For
Bruce Masse, an environmental archaeologist at Los Alamos National
Laboratory, there is no confusion as he looks at this ancient
petroglyph, scratched into a rock by a Native American shaman. "You
can't tell me that isn't a comet," he says.
 src="http://www.sott.net/image/image/4628/medium/fenambosy_escarpment.jpg" /> |
| ©Discover |
| The Fenambosy chevrons at the tip of Madagascar. Image courtesy of Dallas Abbott |
In Masse's interpretation, the petroglyph commemorates a comet that
streaked across the sky just a few years before Europeans came to this
area of New Mexico. But that event is a minor blip compared to what he
is really after. Masse believes that he has uncovered evidence that a
gigantic comet crashed into the Indian Ocean several thousand years ago
and nearly wiped out all life on the planet. What's more, he thinks
that clues about the catastrophe are hiding in plain sight, embedded in
the creation stories of cultural groups around the world. His
hypothesis depends on a major reinterpretation of many different
mythologies and raises questions about how
href="http://news.nationalgeographic.com/news/2003/01/0128_030128_comets.html">frequently major
asteroid impacts occur. What scientists know about such collisions is
based mainly on a limited survey of craters around the world and on the
moon. Only 185 craters on Earth have been identified, and almost all
are on dry land, leaving largely unexamined the 70 percent of the
planet covered by water. Even among those on dry land, many of the
craters have been recognized only recently. It is possible
that Earth has been a target of more meteors and comets than scientists have suspected.
Masse's epiphany came while poring over Hawaiian oral histories
regarding the goddess Pele and wondering what they might reveal about
the lava flows that episodically destroy human settlements and create
new tracts of land. He reasoned that even though the stories are often
clouded by exaggerations and mystical explanations, many may refer to
actual incidents. He tested his hypothesis by cross-checking carbon-14
ages for the lava flows against dates included in royal Hawaiian
genealogies. The result: Several flows matched up with the specific
reigns associated with them in the oral histories. Other myths, Masse
theorizes, hold similar clues.
Masse's biggest idea is that some 5,000 years ago, a 3-mile-wide
ball of rock and ice swung around the sun and smashed into the ocean
off the coast of Madagascar. The ensuing cataclysm sent a series of
600-foot-high tsunamis crashing against the world's coastlines and
injected plumes of superheated water vapor and aerosol particulates
into the atmosphere. Within hours, the infusion of heat and moisture
blasted its way into jet streams and spawned superhurricanes that
pummeled the other side of the planet. For about a week, material
ejected into the atmosphere plunged the world into darkness. All told,
up to 80 percent of the world's population may have perished, making it
the single most lethal event in history.
+++
Up to 80 percent of the world's population may have perished.
Why, then, don't we know about it? Masse contends that we do. Almost every culture has a legend about a
href="http://history-world.org/floods.htm">great flood,
and - with a little reading between the lines - many of them mention
something like a comet on a collision course with Earth just before the
disaster. The Bible describes a deluge for 40 days and 40 nights that
created a flood so great that Noah was stuck in his ark for two weeks
until the water subsided. In the Gilgamesh Epic, the hero of
Mesopotamia saw a pillar of black smoke on the horizon before the sky
went dark for a week. Afterward, a cyclone pummeled the Fertile
Crescent and caused a massive flood. Myths recounted in indigenous
South American cultures also tell of a great flood.
"These stories are all exactly what you would expect from the
survivors of a celestial impact," Masse says, leafing through
2,000-year-old drawings by Chinese astronomers that show comets of all
shapes and sizes. "When a comet rounds the sun, oftentimes its tail is
still being blown forward by the solar winds so that it actually
precedes it. That is why so many descriptions of comets in mythology
mention that they are wearing horns." In India, he notes, a celestial
fish described as "bright as a moonbeam," with a horn on its head,
warned of an epic flood that brought on a new age of man.
Among 175 flood myths, Masse found two of particular interest. A
Hindu myth describes an alignment of the five bright planets that has
happened only once in the last 5,000 years, according to computer
simulations, and a Chinese story mentions that the great flood occurred
at the end of the reign of Empress Nu Wa. Cross-checking historical
records with astronomical data, Masse came up with a date for his
event: May 10, 2807 B.C.
On its own, the mythological evidence is weak, as even Masse
recognizes. "Mythology can help us hypothesize about events that might
have occurred," he says, "but to prove the reality of them, we have to
go beyond myths and search for physical evidence."
In 2004, at a conference of geologists, astronomers, and
archaeologists, Masse outlined his evidence for a world-ravaging impact
in the middle of the Indian Ocean. Ted Bryant, a geomorphologist at the
University of Wollongong in New South Wales, Australia, was intrigued
and enlisted the help of Dallas Abbott, an assistant professor at the
Lamont-Doherty Earth Observatory at Columbia University. In 2005, they
formed the Holocene Impact Working Group (referring to the geological
period covering the last 11,000 years) to seek out the geological
signatures of a megatsunami. If a 600-foot-high wave ravages a
coastline, it should leave a lot of debris behind. In the case of waves
generated by asteroid impacts, the debris they leave in their wake is
believed to form gigantic, wedge-shaped sandy structures - known as
chevrons - that are sometimes packed with deep-
oceanic microfossils dredged up by the tsunami.
When Abbott began searching satellite images on Google Earth, she
saw dozens of chevrons along shorelines and inland in Africa and Asia.
The shape and size of these chevrons suggest that they might have been
formed by waves emanating from the impact of a comet slamming into the
deep ocean off Madagascar. "The chevrons in Madagascar associated with
the crater were filled with melted microfossils from the bottom of the
ocean. There is no explanation for their presence other than a cosmic
impact," she says. "People are going to have to start taking this
theory a lot more seriously." The next step is to perform carbon-14
dating on the fossils to see if they are indeed 5,000 years old.
Meanwhile, Bryant contends that
href="http://www.ldeo.columbia.edu/users/menke/slides/madagascar06/report.pdf">chevrons found
(pdf) 4 miles inland from the shore of Madagascar were formed by a wave
that traveled 25 miles along the coast, moving almost parallel to the
shoreline. "Neither erosion nor any other terrestrial process could
have caused these formations. The biggest marine landslide ever
recorded happened 7,200 years ago off the coast of Norway, and there
was a tsunami, but it was a far cry from leaving deposits 200 meters
above sea level," Bryant says.
Not everyone is convinced, to say the least. "I don't believe the
evidence of a crater off Madagascar, and the impetus is on Abbott to
prove it," says Jay Melosh, an impact expert at the University of
Arizona and an outspoken critic of the theory. To make a case for the
impact, Melosh says, Abbott "should be finding layers of glassy
droplets and fused rock in sea-core samples, the sorts of things we
find at all other similar impact sites."
On the other hand, a lot remains unknown about impacts. As recently
as 60 years ago, some geologists believed that the Barringer Meteor
Crater in Arizona - now considered the prototypical impact scar - was
caused by a volcanic explosion, and they regarded impacts as a minor if
not inconsequential influence on Earth's history. Just 25 years ago,
Luis and Walter Alvarez raised eyebrows with their idea that an
asteroid collision helped kill off the dinosaurs. So Abbott continues
to hunt for evidence that will clinch the idea that Noah's flood was
yet another example of extraterrestrial meddling. "It is still up to us
to prove it, but if we have unequivocal impact ejecta," she says,
Melosh "is going to have to eat his words."
Meteor theory's impact: Cosmic blows could occur
more frequently
By Sandra Blakeslee
The New York Times
Tue, 14 Nov 2006 12:00 EST
Most astronomers doubt that any large comets or asteroids have
crashed into the Earth in the past 10,000 years. But the self-described
"band of misfits" that make up the two-year-old Holocene Impact Working
Group say astronomers simply have not known how or where to look for
evidence.
Scientists in the working group say the evidence for such impacts
during the past 10,000 years, known as the Holocene epoch, is strong
enough to overturn current estimates of how often the Earth suffers a
violent impact on the order of a 10-megaton explosion. Instead of once
in 500,000 to 1 million years, as astronomers now calculate,
catastrophic impacts could happen every few thousand years.
At the southern end of Madagascar lie four enormous wedge-shaped
sediment deposits, called chevrons, that are composed of material from
the ocean floor. Each covers more than 100 square kilometers with
sediment hundreds of meters deep.
On close inspection, the chevron deposits contain deep-ocean
microfossils that are fused with a medley of metals typically formed by
cosmic impacts. And all of them point in the same direction - toward
the middle of the Indian Ocean where a newly discovered crater, 29
kilometers, or 18 miles, in diameter, lies 3,800 meters, or 12,500
feet, below the surface.
The explanation is obvious to some scientists. A large
asteroid or comet, the kind that could kill a quarter of the world's
population, smashed into the Indian Ocean 4,800 years ago, producing a
tsunami at least 183 meters thigh, about 13 times as big as the one
that inundated Indonesia nearly two years ago. The wave carried the
huge deposits of sediment to land.
Most astronomers doubt that any large comets or asteroids have
crashed into the Earth in the past 10,000 years. But the self-described
"band of misfits" that make up the two-year-old Holocene Impact Working
Group say astronomers simply have not known how or where to look for
evidence.
Scientists in the working group say the evidence for such impacts
during the past 10,000 years, known as the Holocene epoch, is strong
enough to overturn current estimates of how often the Earth suffers a
violent impact on the order of a 10-megaton explosion. Instead
of once in 500,000 to 1 million years, as astronomers now calculate,
catastrophic impacts could happen every few thousand years.
The researchers, who formed the working group after finding one
another through an international conference, are based in the United
States, Australia, Russia, France and Ireland. They are established
experts in geology, geophysics, geomorphology, tsunamis, tree rings,
soil science and archaeology, including the structural analysis of
myth. Their efforts are just getting under way, but they will present
some of their work at the American Geophysical Union meeting in
December in San Francisco.
This year the group started using Google Earth, a free source of
satellite images, to search the globe for chevrons, which they
interpret as evidence of past giant tsunamis. Scores of such sites have
turned up in Australia, Africa, Europe and the United States.
When the chevrons all point in the same direction to open water,
Dallas Abbott, an adjunct research scientist at Lamont-Doherty Earth
Observatory in Palisades, New York, uses a different satellite
technology to look for oceanic craters. With increasing frequency, she
finds them, including an especially large one dating back 4,800 years.
So far, astronomers are skeptical but willing to look at the
evidence, said David Morrison, a leading authority on asteroids and
comets at the NASA Ames Research Center in California.
Surveys show that as many as 185 large asteroids or comets hit the
Earth in the far-distant past, although most of the craters are on
land. No one has spent much time looking for craters in the deep ocean,
Morrison said, assuming that young ones do not exist and that old ones
would be filled with sediment.
Astronomers monitor every small space object with an orbit close to
the Earth. "We know what's out there, when they return, how close they
come," Morrison said. Given their observations, "there is no reason to
think we have had major hits in the last 10,000 years," he continued,
adding, "But if Dallas is right and they find 10 such events, we'll have a real contradiction on our hands."
Peter Bobrowski, a researcher of natural hazards at the Geological
Survey of Canada, said that "chevrons are fantastic features" but do
not prove that megatsunamis are real. There are other interpretations
for how chevrons are formed, Bobrowski said, and it is up to the
working group to prove its claims.
Ted Bryant, a geomorphologist at the University of Wollongong in
Australia, was the first person to recognize the palm prints of
megatsunamis. Large tsunamis of nine meters or more are caused by
volcanoes, earthquakes and submarine landslides, he said, and their
deposits have different features.
Deposits from megatsunamis contain unusual rocks with marine oyster
shells, which cannot be explained by wind erosion, storm waves,
volcanoes or other natural processes, Bryant said.
"We're not talking about any tsunami you're ever seen," Bryant said.
"Aceh was a dimple. No tsunami in the modern world could have made
these features. End-of-the-world movies do not capture the size of
these waves."
For example, Bryant identified two chevrons found more than six
kilometers inland near Carpentaria in north- central Australia. Both
point north. When Abbott visited a year ago, he asked her to find the
craters.
To locate craters, Abbott uses sea-surface altimetry data.
Satellites scan the ocean surface and log the exact height of it.
Underwater mountain ranges, trenches and holes in the ground disturb
the Earth's gravitational field, causing sea-surface heights to vary by
milimeters. Within 24 hours of searching the shallow water north of the
two chevrons, Abbott found two craters.
"We think these two craters are 1,200 years old," Abbott said. The chevrons are well-preserved and date to about the
same time.
Abbott and her colleagues have located chevrons in the Caribbean,
Scotland, Vietnam and North Korea, and several in the North Sea.
But Madagascar provides the smoking gun for geologically recent
impacts. In August, Abbott, Bryant and Slava Gusiakov, from the
Novosibirsk Tsunami Laboratory in Russia, visited the four huge
chevrons to scoop up samples.
Last month, Dee Breger, director of microscopy at Drexel University
in Philadelphia, looked at the samples under a scanning electron
microscope and found benthic foraminifera, tiny fossils from the ocean
floor, sprinkled throughout. Her close-ups revealed splashes of iron,
nickel and chrome fused to the fossils.
When a chondritic meteor, the most common kind, vaporizes upon
impact in the ocean, those three metals are formed in the same relative
proportions as seen in the microfossils, Abbott said.
Breger said the microfossils appear to have melded with the
condensing metals as both were lofted up out of the sea and carried
long distances.
About 1400 kilometers southeast from the Madagascar chevrons, in
deep ocean, is Burckle Crater, which Abbott discovered last year.
Burckle Crater has not been dated, but Abbott estimates that it is
4,500 to 5,000 years old.
It would be a great help to the cause if the National Science
Foundation sent a ship equipped with modern acoustic equipment to take
a closer look at Burckle, said William Ryan, a marine geologist at the
Lamont-Doherty observatory. "If it had clear impact features, the
nonbelievers would believe," he said.
But they might have more trouble believing one of the scientists,
Bruce Masse, an environmental archaeologist at the Los Alamos National
Laboratory in New Mexico. He thinks he can say precisely when the comet
fell: on the morning of May 10, 2807 B.C.
Masse analyzed 175 flood myths from around the world and tried to
relate them to known and accurately dated natural events like solar
eclipses and volcanic eruptions. Among other evidence, he said, 14
flood myths specifically mention a full solar eclipse, which could have
been the one that occurred in May 2807 B.C.
Half the myths talk of a torrential downpour, Masse said. A third
tells of a tsunami. Worldwide, they describe hurricane-force winds and
darkness during the storm. All of these could come from a megatsunami.
Of course, extraordinary claims require extraordinary proof, Masse said, "and we're not there yet."
href="http://timesofindia.indiatimes.com/Asteroids_may_return_after_deflection/articleshow/2554356.cms">Asteroids may return after
deflection
The Times of India
Tue, 20 Nov 2007 14:35 EST
London: A new study by scientists suggests that asteroids which
are deflected on a collision course with Earth are likely to return for
another potential clash.
According to the study presented to the US House Science and
Technology Committee last week, methods like nuclear explosions might
deflect an asteroid temporarily, but it does not guarantee safety next
time its orbit brings it close.
Rusty Schweickart, who heads an asteroid research group, told the
committee that the effects of powerful blasts are hard to predict,
especially if the Earth's gravitational pull acts on the object.
"An asteroid could pass through one of the 'keyholes' that would
nudge it back onto a collision course with Earth," Schweickart said.
"So once diverted, it might need to be steered past Earth to prevent
this," he added.
At the same hearing, members attacked NASA for ignoring smaller asteroids.
Krzysztof Czart
Astronomia.pl
Thu, 22 Nov 2007 09:41 EST
 src="http://www.sott.net/image/image/4743/medium/holmes_sequence_art.jpg" /> |
| ©Nicolaus Copernicus University in Toruń. |
| Sequence of images of Comet 17P/Holmes obtained with the TSC 60/90 telescope in the V filter. They show the increase in the comet's envelope size. The colours are chosen here in order to best show the cometary nucleus (the bright point in the centre) and matter moving away from the nucleus (to the right of the nucleus). |
Comet 17P/Holmes has been intriguing astronomers since the end
of October, when its sudden outburst in brightness, the biggest in the
history of comet research, was observed. Scientists from Nicolaus
Copernicus University in Torun in Poland have published a series of
images illustrating the evolution of the comet.
Astronomers from the Torun Centre for Astronomy of Nicolaus
Copernicus University in Torun (Poland) pointed their 0.9 m optical
telescope at the comet. At optical wavelengths, they obtained many
images. The first images were obtained on 26th October, three days
after the outburst. The following images were taken on 2nd, 8th, 10th
November and finally on 15th November.
By composing these photos into a sequence of images using the same
scale in each picture, the increase in the size of the comet's envelope
can be seen. The comet's envelope on November 15th was seven times
bigger than that of 26th October. On the website of the Torun Centre for Astronomy
a movie presenting the comet, obtained with 0.6 m telescope, is available.
17P/Holmes is now 1.6 astronomical units (nearly 250 million
kilometers) from the Earth. The comet-Earth distance is increasing. The
next return of Comet Holmes is expected in about 7 years' time.
"We have been doing observations to detect fast changes in
brightness of the nucleus, over a range of minutes or even seconds. Our
data do not show changes of brightess on this time scale during one
night session." said Ernest Swierczynski, student and one of the
observers of the comet from the Nicolaus Copernicus University.
"From experience with similar comets, astronomers know that
after a rapid outburst in brightness during about 2.5 days, a comet
should then return back to its previous brightness in about 20-30 days.
17P/Holmes does not behave according to this rule, it is still bright,
even though it is almost one month since the outburst (the comet's outburst happened around 23th October)." said Dr Maciej
Mikolajewski from Nicolaus Copernicus University.
The comet can be seen in Perseus, near the brightest star of this
constellation. 17P/Holmes' brightness was 3 magnitudes on 15th
November. It is recommended to watch it with binoculars on a non-cloudy
night.
The Torun Centre for Astronomy is an astronomical observatory of
Nicolaus Copernicus University, located 10 km north of Torun city in
central Poland. Among its telescopes are 0.6 m and 0.9 m optical
telescopes and 15 m and 32 m radiotelescopes. Nicolaus Copernicus University in Torun is
one of the biggest universities in Poland, with about 40,000 students.
More information:
* Torun Centre for Astronomy - images of the
comet
 src="http://www.sott.net/image/image/4744/medium/holmes_sequence_V.jpg" /> |
| ©Nicolaus Copernicus University in Toruń. |
| Sequence of images of Comet 17P/Holmes obtained with the TSC 60/90 telescope in the V filter. They show the increase in the comet's envelope size. Exposition times varied from 8 to 300 seconds. |
 src="http://www.sott.net/image/image/4745/medium/holmes_BVR.jpg" /> |
| ©Nicolaus Copernicus University in Toruń. |
| Photo of Comet 17P/Holmes taken on 2.11.2007 with the TSC 60/90 telescope (0.9 m diameter). The image is created from photos in the B, V and R filters. |
 src="http://www.sott.net/image/image/4747/medium/holmes_V_art.jpg" /> |
| ©Nicolaus Copernicus University in Toruń. |
| Image of Comet 17P/Holmes taken in the V filter on 10.11.2007 with the TSC 60/90 telescope (0.9 m diameter). The colour palette was chosen to emphasize the cometary nucleus (the bright point in the centre) and the comet's envelope. |
 src="http://www.sott.net/image/image/4748/medium/holmes_V.jpg" /> |
| ©Nicolaus Copernicus University in Toruń. |
| Image of Comet 17P/Holmes taken in V filter on 10.11.2007 with the TSC 60/90 telescope (0.9 m diameter). |
Translation: Krzysztof Czart, Boud Roukema
Sira Habibu
The Star
Sat, 24 Nov 2007 16:31 EST
The mystery "blast" that rocked Kuala Terengganu, Dungun and Marang
in Terengganu for several seconds on Friday turned out to be sonic boom
from the newly-acquired state-of-the-art Sukhoi fighter jet.
Two of the fighter jets were involved in a non-combatant training in
preparation for the Langkawi International Maritime and Aerospace
(LIMA) air show.
Royal Malaysian Air Force (RMAF) public relations officer Maj
Zulkiflee Abdul Latiff said the fighter jets travelled at supersonic
speed, emitting loud sonic booms.
"We hope the people in Terengganu do not panic upon hearing the sound,'' he said.
RMAF cleared the air following reports in the media that the
"mysterious blast" shook high-rise buildings, causing some dwellers to
run out of their homes.
The Star office in Kuala Terengganu was inundated with calls on
Friday from people who wanted to know the cause of the 4.10pm "blast".
Zulkiflee, when contacted, said air force pilots need to undergo
training exercises, not only for the air show but also for defence
purposes.
Malaysia acquired six Sukhoi fighter jets from Russia recently.
"The fighter jets were flying more than 10,000m above sea level,''
he said, adding that the training exercise commenced on Friday.
"The exercises are being carried out in the interest of the nation,'' he said.
Jan Pomierny
SOHO
Fri, 30 Nov 2007 04:44 EST
Michal Kusiak, a student of astronomy at
Jagiellonian University in Krakow and an editor of Astronomia.pl has
discovered a new comet. This young astronomy enthusiast found the
object in images sent back to Earth by the SOHO Solar Observatory.
Information on the discovery has been already published on a Web Site
of the British Astronomical Association.
 src="http://www.sott.net/image/image/4768/medium/kusiakkomet.jpg" /> |
| ©SOHO |
| Comet belonging to the Kreutz family |
Michal Kusiak discovered the comet on 24th November. Soon after his
discovery was confirmed by an observer from China, Bo Zhou. Currently
the object awaits the confirmation of its orbit by the coordinator of
the SOHO Comets Programme, Karl Battams. The official confirmation of
the discovery is expected any day soon.
Kusiak's comet belongs o the Kreutz family, that is, to a formation
of comets whose perihelion (the greatest distance of the orbit away
from the Sun) is situated in the vicinity of the photosphere of our
star. Such a small distance from the Sun results in total evaporation
of almost all objects belonging to the family.
Michal Kusiak discovered the previously unknown object in images
taken by the SOHO Solar Observatory. In orbit since 1995, the
instrument has provided loads of data for heliophysicists, yet also
astronomers have benefited from its capabilities, with more than 1300 comet discoveries so far.
Comets are spotted quite often in images taken by the LASCO
Coronograph, a component of the SOHO. They are usually small objects
and their number is so great that also amateur astronomers have been
involved in their discoveries. These astronomy enthusiasts analyse
images and report any 'suspected' objects. Polish amateur-astronomers
are the strongest group in the project. Last year it was the Polish
student who became famous as regards comet discoveries. Arkadiusz
Kubczak, from Piotrkow Trybunalski, discovered the thousandth SOHO
comet belonging to the Kreutz family.
Michal Kusiak comes from Zywiec and is currently a student of
astronomy at Jagiellonian University in Krakow. He has participated in
the SOHO Comets Projects for three years. The comet discovered by the
student is his first discovery, yet he also contributed to the
discoveries made by Arkadiusz Kubczak, whom he introduced to the
comet-search project.
In order to participate in the project one needs to have access to a
computer and a permanent connection to the Internet. The person must
also be very patient and commit him/herself to conducting systematic
analyses.
More information:
* Official SOHO Comets Project
[ Author: Astronomia.pl - Jan Pomierny ]
[ Translation: Marek Łukasik ]
Original Polish version: Nowa polska kometa
Trevor Davis
Oregon Daily Emerald
Sat, 01 Dec 2007 15:54 EST
A group of University scientists have proposed a controversial new theory about the end of the last ice age
For the record, they're not crazy.
But they do admit their theory is out there.
 src="http://www.sott.net/image/image/4827/medium/sh1h0827.png" /> |
| ©Ryan Heidt |
| Two University researchers theorize that a comet may have hit North America about 13,000 years ago, causing an end to several species of animals near the end of the last ice age. |
University researchers Douglas Kennett and Jon Erlandson are part of a
group of scientists proposing that a comet or asteroid hit North
America about 13,000 years ago - near the end of the last ice age - and
contributed to major events in the continent's history, including the
die-off of horses, mammoths and other large mammals around the same
time.
The theory is turning decades of research on its head. The die-off
of animals is usually explained by humans over-hunting the animals or
an abrupt climate change.
"There are people who have made their whole careers on human hunters
causing the extinction of animals," Erlandson said. "They've been
writing about it for 40 years. There are some people who are not likely
to be really happy with this theory."
Researchers say the comet - a ball of ice, rock and dust from outer space - hit the Laurentide ice sheet in Canada.
"It wouldn't have left a crater because it would have exploded and
sent a shower of debris and chunks of ice," said Erlandson, adding the
impact would have been ice on ice.
Heat from impact may have sparked fires across the continent, and
the melting of the ice sheet may have caused flooding. Researchers say
the comet may have contributed to human population reduction and
localized animal extinction.
Researchers say the comet may have helped cause a cold climate
period that lasted for about 1,300 years, called the Younger Dryas, and
may have wiped out or fragmented the prehistoric Clovis tribe.
A carbon-rich black layer found at more than 50 sites around North
America is evidence for the impact, according to the article published
in the Proceedings of the National Academy of Sciences. The layer
contains iridium, carbon spherules and fullerenes with helium 3.
Evidence of mammoths and other animals, along with early human hunters,
are found beneath the black mat, but are missing within or above the
strip.
More evidence is found in the Carolina Bays, which are depressions
from New Jersey to Florida. Erlandson says the depressions point toward
the ice sheet, possibly a result of the comet.
The theory, which is known as the "YDB Comet Theory," was first
proposed by University of California at Santa Barbara paleoceanographer
James Kennett, Douglas Kennett's father, Richard Firestone of the
Lawrence Berkeley National Laboratory and Arizona researcher Allen
West. Douglas Kennett often collaborates with his father.
The theory has generated its share of naysayers.
University of Nevada at Reno anthropologist Gary Haynes says he and
archeologist Stuart Fiedel object to the comet theory. In an e-mail, he
listed reasons for the skepticism.
"In spite of what the comet theorists claim, Paleo-Indians thrive
after the time of the supposed comet impact," Haynes said. "Clovis
culture is transformed into Folsom, Dalton and Eastern U.S. variants,
and all of these are much more numerous than Clovis, suggesting a human
population increase, not collapse."
Graduate student Brendan Culleton, who is involved in the research,
admits it's both scary and exciting to be involved in the studies.
"It's a crazy idea," Culleton said. "You should think this is insane when you hear about this."
Science and Nature magazines declined to publish the article.
"If the theory's true, it's the biggest story of the year - maybe the decade," Erlandson said.
Douglas Kennett, who is in Spain on sabbatical, said in an e-mail that there are and will be doubters.
"This is natural given the magnitude of this hypothesis and its
potential significance in the history of our planet," Douglas Kennett
said. "The scale of inquiry is also massive and we have just started to
scratch the surface in terms of this event and its consequences."
Even the researchers themselves say the theory needs more work.
"I'm not 100 percent convinced, but there's tantalizing evidence,"
Erlandson said. "There's a lot more work that needs to be done to
confirm this."
Erlandson said it could take a decade worth of research to prove the theory.
Douglas Kennett said the group needs to replicate some of its
findings at existing localities with more refined techniques, and said
they need to locate additional study sites both in the northern and
southern hemispheres to determine if the effects are global beyond the
effects of the Younger Dryas cold interval.
Erlandson said he will continue to have an open mind when it comes to the theory.
"Science moves on," he said. "You have to be driven by data."
Thomas F. King
About.com: Archaeology
Thu, 06 Dec 2007 15:45 EST
 src="http://www.sott.net/image/image/4958/medium/The_fall_of_Phaethon.jpg" /> |
| ©Gustave Moreau (1826-1898) |
| The Fall of Phaethon |
Italian geologist Luigi Piccardi and archaeologist Bruce Masse recently teamed to co-edit Myth and Geology (2007-Geological Society of London Special Publication 273), the
first professional textbook on the nascent subdiscipline of
geomythology. Geomythology pairs geological evidence of catastrophic
events and reports of such events encoded into the mythological lexicon
of ancient societies.
In the following contributed essay, archaeologist Thomas F. King
discusses Masse's chapter "The archaeology and anthropology of
Quaternary period cosmic impact," in the 2007 Springer Press book
target="_blank">Comet/Asteroid Impacts and Human Society: An Interdisciplinary Approach, edited
by geologist Peter Bobrowsky and astronomer Hans Rickman. The chapter
uses geomythology to investigate the possible catastrophic comet or
asteroid strike which may have led to disaster legends which have come
down to us today.
Do Global Myths Reflect an Ancient Disaster?
Exploring the Nature of Myth
Scientists who model the probabilities of comet and asteroid impacts
on Earth estimate that a really devastating impact--capable of killing
more than a billion people (at today's standards) and wiping out
civilization as we know it--has happened only every million years or
so. Archaeologist Bruce Masse thinks such impacts may have happened
more frequently, or at least more recently than believed by the
astrophysical community. If he's right, the danger posed by near earth
objects (NEOs) is possibly greater than we've thought. Masse's ideas
are detailed in "The archaeology and anthropology of Quaternary period
cosmic impact," a chapter in the 2007 Springer Press book Comet/Asteroid Impacts and Human Society: An Interdisciplinary
Approach, edited by geologist Peter Bobrowsky and astronomer Hans Rickman.
Bruce Masse's Passion
Masse, like many of today's archaeologists, isn't based in a museum
or university, but works for a government agency--in his case, Los Alamos National
Laboratory
in New Mexico. His day job involves managing the more than 2,000
archaeological sites on Laboratory lands--making sure they're not
damaged by the Laboratory's operations. But his passion over the last
few decades has been studying the archaeological and anthropological
record of celestial phenomena and earthly catastrophes. In the Springer
chapter he presents a startling picture of how such events may have
been linked during the course of the Quaternary period--the last 2.6
million years.
Masse became interested in how cosmic phenomena like eclipses and
comet encounters were perceived by ancient people while doing research
in Hawaii in the late 1980s. The genealogical traditions of Hawaiian
royalty, he found, were full of descriptions of things that happened in
the sky--comet encounters, meteor showers, eclipses, supernovae. Some
of the same events are described in historic European, Chinese, and
Muslim records. Masse was able to plot dozens of precise matches
between Hawaiian tradition and the astronomical observations of
literate observers elsewhere in the world. The more he looked at mythology, the less mythical it appeared, where celestial phenomena were
concerned.
Encoding a Cosmic Event
When he thought objectively about how myths come to be, and who
creates and sustains them, it made sense that they would encode
impressive and hard-to-account-for events. "A myth," he says, "is an
analogical story created by highly skilled and trained cultural
knowledge specialists (such as priests or historians) using
supernatural images in order to explain otherwise inexplicable natural
events or processes." The priest doesn't just invent his story of the
sun being eaten by a giant dog; he comes up with it as a means of
explaining an eclipse that has his people scared out of their wits.
Masse began examining both the mythology and the archaeology of
areas around the sites where asteroids or comets were known or
suspected to have fallen to earth during the Quaternary, and especially
during the last 11,000 years, known as the Holocene. Science is aware
of at least twenty-seven known Quaternary impact sites, marked by
craters and often the remnants of meteoritic iron and melted stone.
Other impacts are known from the presence of glassy melts and tektites
created by an impact or explosion in the atmosphere (an airburst).
Virtually all are on land, where scientists have been able to record,
study, and date them using radiocarbon age determination and other
geophysical methods. Since the Earth's land masses make up only about a
third of the planet's surface, it follows that in the last 2.6 million
years there have been roughly 75 comet/asteroid strikes potentially big
enough to leave physical signs on the ground, with even larger numbers
striking the oceans. Few of these were big enough to have wiped out a
civilization had one existed in the neighborhood, but each one could
have killed a lot of our ancestors.
Archaeological Traces of Holocene Impacts
We have no myths extending back 2.6 million years, of course, but
myths have survived in some cultures for hundreds and even thousands of
years (Consider Jason and the
Argonauts).
So it isn't outlandish to think that Holocene impacts might be
reflected in the myths of nearby peoples. They might also have left
archaeological traces. Masse began to compile the results of
ethnographic, oral historical, and archaeological studies in areas
surrounding known and probable Holocene impact sites, and he found
evidence suggesting that such traces do exist. At Saaremaa Island
in Estonia, for example, where a meteor is known to have struck
sometime between about 6400 and 400 BC, myths speak of a god that flew
to the island along the track the meteor is calculated to have taken,
and of a time when the island burned.
Archaeological and paleobotanical evidence suggests a
multi-generational break in human occupation and farming in the area
beginning sometime between 800 and 400 BC, and a village about 20 km
from the impact crater shows evidence of having burned at about the
same time. At Campo de Cielo
in Argentina, a crater field littered with small meteorites, dated to
between 2200 and 2700 BC, myths recorded in the early 20th century
reportedly tell of an impact by a piece of the sun. In most cases where
impacts are well documented, however, no pertinent archaeological or
ethnographic studies have been reported, and in most places where myths
or archaeology suggest the possibility of cataclysms, no obvious
craters or tektite fields have been yet documented by geophysicists.
But if myths can codify records of celestial phenomena, as Masse's
Hawaiian work shows, then a consistent regional pattern of mythic
accounts describing catastrophe from the sky might suggest the
existence of an impact event that has not yet been identified
geophysically, and indicate fruitful locations for geophysical
investigation. To pursue this possibility, Masse and his
geologically-trained brother Michael undertook a comprehensive analysis
(reported in Myth and Geology) of over four thousand myths
recorded throughout South America east of the Andes, conveniently
gathered into a database by UCLA. What particularly stood out in the
analysis were 284 myths describing cataclysms that, in the view of
those reciting the story, caused more or less universal death,
triggering a new creation of humanity.
Destruction Myths
The Masse brothers found that the destruction myths almost always described one or more of four phenomena--a great flood, a world
fire, the falling of the sky, and a great darkness. When
two or more of these phenomena were described by myths in the same
culture, they fell into a consistent sequence. At least in the Gran
Chaco, the flood was earliest, then the fire, and more recently the
falling sky and the darkness. Their analysis suggested that the last
two events--falling sky and great darkness--reflect aspects of volcanic
eruptions. The world fire and great flood myths are different.
Some of the world fire stories quite explicitly describe the impacts
of celestial objects. The Toba-Pilaga of the Gran Chaco, for example,
speak of a time when fragments of the moon fell to earth, igniting a
fire that incinerated the whole world, burning people alive and leaving
corpses floating in the lagoons. Evidence suggests that this event may
be associated with the Campo del Cielo impact crater field in northern
Argentina dated around 4500 years ago. In the highlands of Brazil there
are stories of Sun and Moon fighting for a red feather ornament, which
fell to earth together with hot coals that started a world fire so hot
that even the sand burned. The UCLA database contains a number of such
stories.
Do these myths reflect one or more cataclysmic fires caused by
cosmic impacts that devastated eastern South America? Masse thinks it
likely enough to justify more research.
There Was a Great Flood....
But the stories of the great flood give even more cause for thought.
In South America it is the most commonly reported worldwide
catastrophe. Masse found it in 171 myths among groups scattered from
Tierra del Fuego in the south to the far northwest part of the
continent. It is consistently the earliest disaster, always reported
prior to the world fire, falling sky and darkness. In the vast majority
of cases only a single great flood is described, which Masse thinks
makes it unlikely that it represents recollection of local or regional
flooding. And South America isn't the only place it occurs.
Of course, the biblical story of Noah's flood is well known, as is the related Mesopotamian story of
href="http://ancienthistory.about.com/od/gilgamesh/g/Gilgamesh.htm" target="_blank">Gilgamesh
and the flood. Many explanations have been advanced for these flood
stories and others in the Middle East, most involving regional events
like the sudden flooding of the Black Sea in the early Holocene. Back
in 1994 Alexander and Edith Tollmann foreshadowed Masse's research by
proposing a cosmic impact as the cause of a worldwide flood in about
9600 BC. The Tollmann's proposal has been widely rejected by scholars,
and Masse is very critical of it, saying that the Tollmanns "mix the
Biblical creation myth with flood myths, and make generalizations not
warranted by the myths they use." Masse emphasizes the need to apply to
myth research the same rigorous standards applied to other kinds of
scientific study.
Attempting to apply such standards, Masse examined a worldwide
sample of flood myths in 175 different cultures all over the world
(most gathered and reported by noted anthropologist Sir James George Frazer
in the early 1900s)--representing about 15% of the "great flood" myths
that have been published in English. He hypothesized that if these
myths reflected a single worldwide cataclysm, then the information
encoded in them--the environmental aspects of the flood that they
describe--should form a pattern across cultures that is consistent with
a single event. Collectively they should create a plausible description
of the event as experienced in different parts of the world, and that
description should be consistent with archaeological and geophysical
data. He analyzed his 175 myths with this hypothesis in mind, and found
that "only a globally catastrophic deep-water oceanic comet impact can
account for all the environmental information encoded in the corpus of
worldwide flood myths."
Tsunamis and Rainstorms
The majority of the myths describe a torrential, long-duration
rainstorm, in many cases accompanied by a huge tsunami. The water is
often described as hot, sometimes coming as hot ocean swells, sometimes
as burning rain. The described durations of the flood storm in the
various myths, when plotted, form a bell-shaped curve with the great
majority clustering between four and ten days. Tsunamis are described
as extending between 15 and 100 km inland. Survivors typically find
refuge in places between 150 and 300 meters above sea level.
Supernatural creatures are associated with the flood storm in nearly half the cases Masse studied. Typical
are giant snakes or water serpents, giant birds, giant horned snakes, a
fallen angel, a star with fiery tail, a tongue of fire, and similar
elongated things in or from the sky. Looking in detail at
descriptions in the mythology, particularly those of the Indian
subcontinent, Masse sees a close resemblance to the naked-eye
appearance of a near-earth post-perihelion comet.
Sixteen of the myths Masse examined describe when the flood storm
occurred in terms of seasonal indicators. Fourteen myths are from
Northern Hemisphere groups, and place the event in the spring. The one
from the Southern Hemisphere places it in the fall--that is, spring
north of the equator. Seven stories give the time in terms of lunar
phase--six at the time of the full Moon, another two days later.
Stories from Africa and South America say it happened at the time of a
lunar eclipse, which can only occur when the Moon is full. A 4th
century BC Babylonian account specifies a full Moon in late April or
early May.
Chinese sources recount how the cosmic monster Gong Gong knocked
over a pillar of heaven and caused flooding toward the end of the reign
of Empress Nu Wa, around 2810 BC. The 3rd century BC Egyptian historian
Manetho says there was an "immense disaster" (but doesn't say what
kind) during the reign of the pharaoh Semerkhet,
around 2800 BC. The tomb of Semerkhet's successor, Qa'a, was built of
poorly dried mud bricks and timbers showing unusual decay; the
following pharaohs of the second dynasty relocated the royal cemetery
to higher ground. Masse's analysis of astrological references in
multiple myths from the Middle East, India and China--describing
planetary conjunctions associated with the flood storm, whose actual
times of occurrence can be reconstructed using contemporary astronomy
software--leads him to conclude that the event happened on or about May
10, 2807 BC.
What was it that happened? Masse thinks the myths provide clues to
that, too. For one thing, they report massive rain, falling for days at
a time. This turns out to be exactly what can be expected if a
large comet plunged into the deep ocean--it would loft nearly ten times
its mass of water into the upper atmosphere, where it would spread
widely and then fall, taking days to empty the skies. A large
impact in the ocean would also cause gigantic tsunamis, as many of the
myths report. In India, for example, Tamil myths tell of the sea
rushing 100 km inland, a hundred meters deep.
Plotting Mythic Events: The Burckle Crater
Plotting the distribution of great flood myths together with
specific reported phenomena like directions from which great winds blew
or tsunamis came, Masse finds that the most efficient way to account
for them is by positing a very large comet impact in the central or
southern Indian Ocean. This might not account very well for flood myths
in the Americas, but Masse thinks that flooding there could have
resulted from partial disintegration of the incoming comet, with two or
more pieces falling on different parts of the earth over a period of
hours or days. Some of the myths speak of multiple events
happening in close succession. But the really big impact, he thinks,
the most lethal of the bunch, occurred somewhere south of Madagascar.
Where, it turns out, there is a possible impact crater on the sea floor 1500 kilometers southeast of Madagascar. Named
href="http://tsun.sscc.ru/proj.htm" target="_blank">Burckle Crater
and discovered only recently by Masse's colleague Dallas Abbott from
Lamont Doherty Earth Observatory, it is a little under 30 km in
diameter and is visible on bathymetric maps. Stratigraphic cores taken
near there suggest that it is an impact crater, but are not definitive.
The Burckle Crater needs more study, but it is 3800 meters deep, so
it's not an easy place to explore. More readily accessible is the
southern coast of Madagascar where recently studied chevron-shaped dune
deposits of potential tsunamic origin may be indicative of giant waves
more than 200 meters in height. Masse and Abbott have joined together
with more than 25 other scientists to form the "Holocene Impact Working
Group," to better explore Burckle Crater, Madagascar, and other
locations bearing potential Holocene physical evidence of impact.
If Masse is right, a comet impact big enough to have devastating
effects on human civilization occurred in 2807 BC--a bit under 5,000
years ago. Other smaller impacts and airbursts have happened since
then--the most recent being at Sikhote Alin near
Vladivostok in 1947. None of these were as devastating as the K-T event
that doomed the dinosaurs, but many were big enough to wipe out cities
or whole nations if there had been any in the vicinity at the time. And
the 2807 BC event, to judge from the myths, made the December 2004
Indian Ocean tsunami look like a ripple on the beach.
The Past as Prologue
Would confirmation of a civilization-killing impact 5,000 years ago
mean that another one is likely tomorrow or the next day? No, but the
more large impacts there have been in the recent past, the more
troubling become our prospects for the future. In fact, in the November
2007 issue of the Proceedings of the National Academy of Sciences,
physicist Richard Firestone and colleagues suggest
that the major climatic perturbations and extinctions at the beginning
of the Younger Dryas event some 12,900 years ago were caused by an
comet impact even more catastrophic than that of the 2807 BC event.
Masse's research highlights the importance not only of studying
Earth's past for evidence of impacts, but of searching space for the
NEOs that may be incoming. It also shows that when it comes to
identifying impacts that have occurred over the last few thousand
years, geophysical research isn't the only game in town. Archaeology
and the study of humankind's oral traditions have unique contributions
to make as well.
Rex Dalton
Nature
Thu, 13 Dec 2007 12:22 EST
Bullet-like pieces of what is thought to be an ancient meteorite
shower have been found embedded in mammoth tusks and bison bone.
The discovery of the 2 - 5 millimetre holes left by meteorites opens
a window into a impact event thought to have happened over Alaska and
Russia tens of thousands of years ago. And it could provide a whole new
way to chart impacts from space.
 src="http://www.sott.net/image/image/5122/medium/news.2007.372.jpg" /> |
| ©Firestone et al. |
| The 'bullet holes' in this tusk are found only on the skyward side. |
The fragments, found in seven mammoth tusks and the skull and horns
of a Siberian bison, match the geochemical composition of iron
meteorites. "We think that the micrometeorites came from an air-burst
of a meteor 30,000 to 34,000 years ago," says Richard Firestone,
co-author of the study and a chemist at the Lawrence Berkeley National
Laboratory in California. "We think a wave of meteoric material sprayed
the region."
Some of the tusks are peppered with hundreds of the fragments, which
had burnt grooves into the bone. All the pieces entered the bones on
the skyward surfaces of the tusks and skull.
The researchers presented their findings on 11 December at the American Geophysical Union meeting in San Francisco.
Motel dream
Strangely, the trail to finding the tusks began at a fossil sale in a motel in Arizona.
Allen West, a self-taught geophysicist based in Arizona, was looking
for evidence of a meteorite that he and his colleagues think caused the
wipe-out of large mammals and the Clovis people in North America some
13,000 years ago. Recalling previous visits to the annual Tucson Gem
and Mineral Show, West says, "A bulb went on in my head; I remembered
seeing a room full of mammoth tusks there." He reasoned that tusks or
antlers of deer or elk might have inadvertently captured exploding
meteoritic material. So he went to a motel that shows the fossils, and
sifted through the tusks.
"I spent two or three hours looking at dirty old tusks, when
suddenly there was a burnt hole," he says. He tested it with a small
magnet, as he knew many meteorites were mostly iron. "Bang; it stuck
right to the hole," he says.
West bought the 60-centimetre tusk for about US$200, and later
headed to the warehouse of the company that he bought it from: Canada
Fossils.
After three days of searching through the company's collection of
some 15,000 tusks, West started to find more evidence of
micrometeorites in a batch from the Yukutia Peninsula in eastern
Siberia. His magnet again repeatedly hit the mark on tell-tale burn
holes.
West bought these tusks too and took them to Firestone and his colleagues for geochemical analysis and radiocarbon dating.
Past blast
The geochemical analysis confirmed that the pieces had a high iron
and nickel content, and were low in titanium, making them more likely
to be from meteorites than from Earth-bound rocks.
The dating showed that most of the tusks were 30,000 to 34,000 years
old, and so not relevant to their theory about the end of the Clovis
people (for more on that theory, see Blast in the past?).
One tusk dated to 21,000 years ago, and the bison skull to 26,000 years
old, but Firestone thinks that the dating of these specimens might have
been affected by contamination of the samples. Future work, he thinks,
will probably show them to be from the same meteorite shower as the
other samples. They plan to refine the dates on all specimens as they
move towards publication.
Firestone and his colleagues note that other scientists have found
evidence that the populations of some large mammals - such as bison,
horses and mammoths - declined about 34,000 years ago. That could go
well with a theory of a meteor impact at that time.
Comment: Note that 30,000 to 34,000 years is almost precisely seven to eight 4,200 year periods, coinciding with the
href="http://www.signs-of-the-times.org/articles/show/134637-
+The+Younger+Dryas+Impact+Event+and+the+Cycles+of+Cosmic+Catastrophes+-+Climate+Scientists+Awakening" target="_blank">Cycle of
Cosmic Catastrophes.
The researchers hope that their find will spur others to look
through fossils for signs of meteor impacts. "We're hoping that museums
and universities will start examining their collections for similar
specimens," says West.
NASA
Mon, 03 Dec 2007 19:50 EST
 src="http://www.sott.net/image/image/5130/medium/Asteroid_Shower.jpg" /> |
| ©Christopher Colley |
Mark your calendar: The best meteor shower of 2007 peaks on Friday, December 14th.
"It's the Geminid meteor shower," says NASA astronomer Bill Cooke of
the Marshall Space Flight Center. "Start watching on Thursday evening,
Dec. 13th, around 10 pm local time," he advises. "At first you might
not see very many meteors - but be patient. The show really heats up
after midnight and by dawn on Friday, Dec. 14th, there could be dozens
of bright meteors per hour streaking across the sky."
The Geminids are not ordinary meteors. While most meteor showers
come from comets, Geminids come from an asteroid - a near-Earth object
named 3200 Phaethon.
"It's very strange," says Cooke. How does an asteroid make a meteor shower?
Comets do it by evaporating. When a comet flies close to the sun,
intense heat vaporizes the comet's "dirty ice" resulting in high-speed
jets of comet dust that spew into interplanetary space. When a speck of
this comet dust hits Earth's atmosphere traveling ~100,000 mph, it
disintegrates in a bright flash of light - a meteor!
Asteroids, on the other hand, don't normally spew dust into space -
and therein lies the mystery. Where did Phaethon's meteoroids come from?
One possibility is a collision. Maybe it bumped against another
asteroid. A collision could have created a cloud of dust and rock that
follows Phaethon around in its orbit. Such collisions, however, are not
very likely.
Cooke favors another possibility: "I think 3200 Phaethon used to be a comet."
Exhibit #1 in favor of this idea is Phaethon's orbit: it is highly
elliptical, like the orbit of a typical comet, and brings Phaethon
extremely close to the sun, twice as close as Mercury itself. Every 1.4
years, Phaethon swoops through the inner solar system where repeated
blasts of solar heat could easily reduce a flamboyant comet to the
rocky skeleton we see today.
If this scenario is correct, Phaethon-the-comet may have produced
many rich streams of dust that spent hundreds or thousands of years
drifting toward Earth until the first Geminid meteors appeared during
the US Civil War. Since then, Geminids have been a regular shower
peaking every year in mid-December.
3200 Phaethon is now catalogued as a "PHA" - a potentially hazardous
asteroid whose path misses Earth's orbit by only 2 million miles. It
measures 5 km wide, about half the size of the asteroid or comet that
wiped out the dinosaurs 65 million years ago, and can be seen through
backyard telescopes - in fact, now is a good time to look:
"3200 Phaethon is flying past Earth just a few days before this
year's Geminid meteor shower," notes Cooke. On Dec. 10th, Phaethon will
be about 11 million miles away shining like a 14th magnitude star in
the constellation Virgo: ephemeris. That's too dim for the naked eye,
he says, but a good target for amateur telescopes equipped with CCD
cameras.
Cooke doesn't expect the flyby to boost the Geminids - "11 million
miles is too distant to affect meteor rates" - but the Geminids don't
really need boosting. "It's always a great shower," he says. "Don't
miss it."
Paul Icamina
All Headline News
Wed, 12 Dec 2007 11:06 EST
Bangor, Maine - Frantic calls from New
Hampshire to Canada about strange lights in the sky had police
scrambling to look for unidentified flying objects only to find out the
fireballs coincided with Monday evening's launch from Kennedy Space
Center in Florida.
A defense agency spokesman described the launch was for a "national security satellite."
Sgt. Derek Strong of the Royal Canadian Mounted Police told the Bangor Daily News
that the orange lights were caused by debris re-entering the earth's
atmosphere and crashing into the ocean off Point Lepreau, New Brunswick.
Ken Stewart of the U.S. Coast Guard said calls were fielded from Portsmouth, N.H., "all the way to Nova Scotia," The Associated Press
reported.
The satellite launch that brought the fireballs that prompted many calls to local police.
Translated from Hebrew
Ynet
Sun, 09 Dec 2007 14:11 EST
Concerned citizens reported to Ynet
about loud sounds of explosions in the area of the Central District.
Some feared it was an earthquake, although the Geophysical Institute
refuted this possibility. Later today the IDF responded that it is
probably a sonic boom.
Several loud explosions were heard this afternoon in the Central
District area. The IDF responded that apparently those were sonic
booms, and the matter is under investigation. They added that during
their activity, IAF makes all the possible effort to avoid interfering
with the citizens' quality of life.
Not long after 16:00, Ynet was flooded with "red email"
reports from concerned readers. Many readers from the Central District
reported extremely loud noises and strong tremors.
According to the readers' reports, there were three sounds of
explosions, with small intervals between them. Some of the readers
reported that they felt the earth trembling, although Geophysical
Institute refuted any possibility of an earthquake.
Jonathan, resident of Ashkelon, said that two explosion sounds were
clearly heard above his house in the north part of the city. "It was a
very strong boom, and the house was trembling. At first I thought that
it was a bomb and immediately went outside to see what's happening, but
couldn't see a thing."
Other reader reported about "two explosions at 16:05, with a two
minutes interval, that shook the street. They sounded from the distance
and caused car alarms to go off."
Or-Yehuda resident reported that three loud booms were heard and
caused light tremor. In Kiriat Ono people reported that booms shook the
houses.
During the last years there were several cases of sonic booms caused by IAF flights above the Israeli sky.
IAF used to cause sonic booms above Gaza. In 2005, the organization
"Doctors for Human Rights" submitted a petition to the high court
against this practice, claiming that those booms cause significant
damage to the civilian population and children in Gaza. The court
claimed in return that this practice has an operational importance and
can't be renounced.
Comment: According
to one of our Israeli readers, those booms were heard and felt along
the coastline (from Ashkelon - South of the country, to Hedera - North
of the country) and not only in the Central District. And although
several reported the sighting of two jet fighters above the sea, it
still doesn't explain the intensity and the distance those booms could
be heard from.
By CHRIS LAMBIE and BRIAN MEDEL Staff Reporters
Halifax Chronicle-Herald
Fri, 14 Dec 2007 18:16 EST
The bright ball of flame that streaked across the winter sky Monday
night wasn't a shooting star - it was a booster rocket that had carried
a U.S. military satellite into orbit.
The fireball was visible along the South Shore as the booster plummeted into the ocean off Nova Scotia.
"We just happened to be looking in a southerly direction and (saw) a
bright ball of yellow-orange flame," Yarmouth firefighter Peter Poirier
said Tuesday.
He was with a crew fighting a house fire in the south end of town
when firefighters spotted the ball of fire in the clear sky. They were
able to track the booster's descent for about 10 seconds before it
vanished.
The light definitely wasn't close, Mr. Poirier said.
"It had that orange glow that would resemble what you'd see from a flare," he said.
"But it was too big, physically, for it to be a flare."
At first, some people thought it was a small plane in trouble.
"All kinds of calls came in," Yarmouth Fire Chief Ken Kelly said Tuesday.
"A few people reported an airplane down."
The spectacular light show came courtesy of the U.S. air force,
which launched the first of a new generation of military communication
satellites Monday from Cape Canaveral, Fla.
The booster stage of the rocket burned up on re-entry far off the
coast, said 2nd Lt. Noel Paine, a spokesman for the rescue
co-ordination centre in Halifax.
"There was a fair amount of debris," Lt. Paine said. "The reason
there were a lot of calls and interest was the debris burning up was
quite visible, possibly from both the Nova Scotia and New Brunswick
coasts."
The navy doesn't know exactly where the booster landed, said Lt.-Cmdr. Mary-Claude Gagne of Joint Task Force Atlantic.
"If we did, we probably would have recovered it, or somebody would
have," she said, noting the projected drop zone for the booster ranged
from 185 to 460 kilometres off Nova Scotia.
The booster was visible because it was burning as it re-entered the atmosphere, Lt.-Cmdr. Gagne said.
"It's no different than a shooting star," she said.
Most satellites are launched near the equator because it saves on
fuel, said Richard Wassersug, an anatomy and neurobiology professor at
Dalhousie University who has worked with NASA to conduct projects in
space.
That makes seeing the rocket booster falling here an extraordinary occurrence.
"It's going to be very rare at this latitude," Mr. Wassersug said.
"It's uncommon to put something into a strongly polar orbit. So it's
going to be rare to have seen boosters off of our coast coming down."
The satellite it was carrying was likely destined for a polar orbit, he said.
It will probably be used to conduct surveillance on the Russians and monitor communications in the Arctic, Mr. Wassersug said.
The booster would have been "pretty huge," he said, noting it was
probably heavily damaged by heat while re-entering Earth's atmosphere.
But the odds of it falling on someone, or a ship, were astronomical.
"There's always the slim possibility of space junk coming down and
hitting someone," Mr. Wassersug said. "Not all this stuff burns up
completely."
Monday marked the 11th flight of an Atlas V rocket from Cape Canaveral.
The Atlas V booster carried a Wideband Global SATCOM satellite into
space. The American satellite system is expected to provide better
communications for marines, soldiers, sailors and airmen.
"Once the satellite we launched (Monday) becomes operational, it
will become the Department of Defence's highest-capacity communications
satellite and provide critical effects for our war fighters,"
Brig.-Gen. Susan Helms, commander of 45th Space Wing in Florida, said
in a news release.
"This mission proves that control of the battlefield really does begin here."
Irene Klotz
Reuters
Fri, 14 Dec 2007 05:53 EST
CAPE CANAVERAL, Florida - Two astronauts on the International Space
Station will make a spacewalk next week to find out if a micrometeoroid
strike damaged a critical part of the outpost's power system, officials
said on Thursday.
The station is not in any danger and is still producing enough power
to support the arrival of a Russian cargo ship this month, said station
deputy program manager Kirk Shireman.
Analysis is under way to determine if changes need to be made to
NASA's plan to launch the space shuttle Atlantis in January with
Europe's Columbus science module on board.
That flight, originally planned for last week, was postponed when
sensors in the shuttle's fuel tank failed during two launch attempts.
NASA had said it would try again no earlier than January 2. But on
it said it had reset the target date to January 10 to give workers more
time with their families during the holidays.
Shireman said the power problem would probably not affect plans to
attach Columbus to the station next month. But flights of Japanese
modules in February and April could be affected.
Without repairs, "we know we can't go too much farther," he said.
Station commander Peggy Whitson and flight engineer Dan Tani are
scheduled for a 6.5-hour spacewalk on Tuesday to inspect two joints
needed to position the station's right-side solar panels toward the sun.
The primary joint, which rotates the panels 360 degrees, was locked in place by spacewalking astronauts in October.
A problem with a second joint, which lets the panels pivot while the
primary joint is locked, surfaced on December 8. "It makes power
generation much more difficult," Shireman said.
Because several independent pieces of equipment were
simultaneously affected, engineers suspect a micrometeoroid strike may
be to blame.
They also theorized a piece of debris may have worked itself free
and floated into an area that shorted out electrical components.
Spare parts to fix the second joint are on board the station, though
if the problem is with the device's cables a repair would have to wait
until supplies arrive on the next cargo ship or aboard the shuttle,
Shireman said.
"This (spacewalk) is a fact-finding mission," he said. "It is hoped
that something the crew sees can help us narrow down the problem."
(Editing by Jane Sutton)
Eric Russell
Bangor Daily News
Sat, 15 Dec 2007 07:59 EST
More strange lights were seen in the skies
over Maine late Thursday night, but it's unlikely they were related to
an incident earlier this week.
An Air Force spokeswoman said Friday that the sighting of "fireballs
in the sky" off Maine's coast Monday evening was almost definitely part
of a U.S. Air Force booster rocket.
Between 10 and 11 p.m. Thursday, Bangor police and Penobscot County
sheriff dispatchers received several calls describing shafts of yellow
and white light that extended from the ground to the sky. Additional
sightings of an orange glow over northern Penobscot County also were
reported.
A meteorologist with the National Weather Service in Caribou said
there was no meteorological explanation for the lights. Rebecca Hupp,
director at Bangor International Airport, said the airport did not
field any calls overnight Thursday.
On Monday evening, reports flooded dispatch centers in Washington
County and New Brunswick describing strange orange lights in the sky.
At first there was concern that a plane had crashed in the Bay of
Fundy, but a quick search by the U.S. Coast Guard revealed that was not
the case.
Air Force Lt. Col. Maria Carl confirmed Friday that the Air Force
launched an Atlas V booster shortly after 5 p.m. Monday from Cape
Canaveral Air Force Station in Florida. It was carrying what she called
National Reconnaissance Office payload, but she didn't elaborate
because it was a classified mission.
Ten minutes after the booster was launched north, an expendable fuel
tank separated and dropped into the Atlantic Ocean about 100 miles off
Nova Scotia, she said.
"Obviously, I don't know for sure what people saw, but based on the
trajectory and the timing, it seems accurate that it would have been
the booster," Carl said Friday.
While her explanation might close the door on Monday's sightings, it
doesn't explain the reports of orange and yellow light shafts seen
Thursday.
"I can't speak to that," the Air Force spokeswoman said, "but we didn't have any additional launches, so that wasn't us."
Comment: That's an odd lack of concern over strange lights in North American air space coming from the air force.
Neil Comins, an astronomy professor at the University of Maine, said
Thursday's light show could have been several things. For example, a
variety of gases glow in the atmosphere.
"It's entirely plausible that what people saw last night was frozen
residue [from the gases] that re-entered the atmosphere," he said.
Comins did not rule out the possibility that Thursday's sighting was related to the incident from Monday.
"There is a slim but not negligible possibility that something in
orbit could have decayed at a slower rate," he said, referring to the
Air Force launch.
While strange reports of lights in the sky occur several times a
year, Comins said, it's uncommon to see two reports in the same week.
"So, in that sense, I can't say, 'No, they are definitely not connected,'" he said.
The lack of a conclusive explanation for either incident this week
has conjured up memories of an incident that was reported 40 years ago
in waters off Nova Scotia.
The "Shag Harbor Incident," which occurred Oct. 4, 1967, is one of the most-documented potential UFO sightings in history.
Similar to Monday's incident, residents of the small Nova Scotia
fishing village of Shag Harbor saw unusual orange lights in the sky.
After that, others saw an object descend toward the water, but instead
of crashing into the ocean, it hovered on the surface, according to
reports by MUFON, a large organization that investigates reports of
unidentified flying objects.
The Bangor Daily News reported that residents of Washington County
and elsewhere in Maine reported strange lights in the sky the same
night.
The Shag Harbor Incident was investigated by the U.S. Coast Guard,
and some reports indicate that an unsuccessful search was conducted.
Because the sightings could not be attributed to any military or civilian launch, the incident quickly gained infamy.
Carl didn't comment on the Shag Harbor Incident but she said that
anytime the Air Force launches a booster, her office gets numerous
calls, so she wasn't surprised this week.
Anne Minard
National Geographic News
Sat, 15 Dec 2007 09:09 EST
An ancient meteor impact in North America sent up waves of rock
fragments that peppered prehistoric mammals with "space shrapnel" about
34,000 years ago, scientists say.
Many of the animals, particularly in the region near present-day Alaska, didn't survive.
That's the story being pieced together by a research team led by
Richard Firestone of the Lawrence Berkeley National Laboratory in
Berkeley, California.
The team had done previous work on a suspected impact that occurred
13,000 years ago. But while looking for evidence of that more recent
blast in mammoth tusks, the scientists found traces of the much older
event.
"The surprise was the tusks were dating back to 30,000 to 34,000 years ago," Firestone said.
"Nobody had thought of it before. It was serendipitous."
The work was presented this week at the fall meeting of the American Geophysical Union in San Francisco, California.
Tiny "Bullet Holes," Micrometeorites Found
While searching for evidence of the more recent cosmic impact, team
member Allen West, an Arizona geophysicist, noticed an odd pattern as
he was combing through thousands of ancient tusks.
He found that the top-facing sides of a few tusks were pockmarked by holes 0.08 to 0.11 inch (2 to 3 millimeters) across.
The pockmarks were found on seven mammoth tusks - most likely from
near Alaska's Yukon River - and the skull and horns of a Siberian bison
(see a map of Alaska).
That the holes were found on only one side of the bones indicated that the impacts came from a single direction, Firestone said.
The researchers believe the damage was caused by micrometeorites,
each less than a millimeter in size, thrown off by an object that
collided with Earth.
The researchers found fossilized meteorites in the holes and
determined that they were rich in iron and nickel but poor in titanium
- chemical traits that suggest celestial and not earthly origins, they
say.
West also discovered that the tiny rocks were highly magnetic. When
he suspended a magnet on a string over the holes, the magnet held fast.
The team additionally found that the bison skull showed bone growth
around the holes, suggesting that the animal had survived the blast.
Catastrophic Event
Firestone said the evidence corroborates previous work done by Ian
Barnes, a paleobiologist at Royal Holloway University of London.
In a paper published in the journal Current Biology in June of this
year, Barnes reported molecular evidence for a die-off of mammoths
around the time of the newly suspected impact.
"We are pretty certain there was one event that occurred in that region," Firestone said.
Barnes agreed the data so far could suggest a connection, but he said it's tenuous at best and more information is needed.
"Brown bears underwent a local extinction in Alaska 35,000 years
ago, and there may be some turnover or reduction of the Alaskan mammoth
population around 35,000 [years ago], but that data hasn't been
published yet," he said.
"Whether it only happened in North America or farther afield, I don't have the data for that yet."
More Tusks Ahead
Firestone and his colleagues expect to submit their work for publication in a scientific journal in the coming year.
Meanwhile, the early evidence has already raised some perplexing questions.
"The big mystery is the nature of the impact," Firestone said.
"We don't know whether a meteor exploded or what happened. It's confounding the impact [experts]."
Barnes pointed out there have been plenty of hazards for Earth's
creatures aside from meteor blasts, including volcanic eruptions and
rapid climate change.
(Read related story: "Volcano
Theory of Dino Die-Off Gets New Support" [November 5, 2007].)
Celestial pockmarks notwithstanding, Firestone hesitated to pin
href="http://science.nationalgeographic.com/science/prehistoric-world/mass-extinction.html?nav=A-Z">mass extinction on any one
event.
"There are all sorts of events that might cause a reduction in
population size, so I'm cautious about ... actually ascribing
causation," he said.
Nevertheless, Barnes called the findings "pretty extraordinary," particularly because they were uncovered so unexpectedly.
"You got to give it to them - it's pretty exciting stuff," he said. "Pretty amazing."
Dave Mosher
livescience.com
Mon, 17 Dec 2007 21:28 EST
Space rocks are blamed for a lot of rough times on Earth, from the
die-off of most marine animals some 250 million years ago to the
disappearance of the dinosaurs 65 million years in the past.
A new theory, however, suggests that catastrophic meteorite impacts
are linked to an explosion in biodiversity about 470 million years ago,
during the Ordovician Period. Within a few million years, the number of
trilobite species and scores of other creatures on Earth jumped at
least three to four times.
Birger Schmitz, a geologist at the University of Lund in Sweden who
worked for more than 10 years to help gather evidence backing up the
claim, is the first to admit that his group's findings are hard to
swallow.
"It seems completely at odds with anyone's expectations," Schmitz
said, "but you have to remember, for example, that it was at first
difficult for many scientists to accept asteroid explanations for the
disappearance of the dinosaurs."
Schmitz and his colleagues detail their findings in the Dec. 16 advance issue of the journal Nature Geoscience.
Smackdown
Just before the jolt to Ordovician life, Schmitz said two massive
bodies in the Asteroid Belt slammed into one another, littering the
solar system with rocks the size of Manhattan island and ranging down
to microscopic bits of dust.
"Even today, more than 20 percent of the meteorites we see came from
this breakup event," Schmitz said. That makes the L-chondrite
meteorites, as they're known, the most common kind to rain down on
Earth.
Such extraterrestrial rocks contain a unique form of radioactive
chromium, so Schmitz and his team were able to figure out precisely
when, how much and how often the cosmic debris slammed into Earth.
"We saw a sudden jump in meteorite material around the time of
increased biodiversity," Schmitz said - greater than 100 times more
material, in fact. "That's a major event, and an incredible coincidence
that I don't think we should ignore," he told LiveScience.com.
Schmitz cautioned that while the two events line up in an uncanny
way, there is still a lot of work left to do to connect the increased
meteorite impacts to inflating biodiversity.
"It took us about 15 years to accumulate data for this finding, and
it's something that isn't just a computer model or simulation. It's
real, tactile evidence," he said of the work, which included slowly
acid-dissolving almost a ton of rock collected from around the world to
sift out bits of chromium.
The scientists compared their meteorite record to layers of
fossilized plants and animals, determining that the cosmic smashup
happened shortly before the biodiversity boost.
"I expect that it will take us another 15 years of playing in the
dirt to get there, to find Ordovician impact craters and beds
associated with this breakup," he said.
Pushing their luck
Schmitz isn't certain exactly how pummeling the planet with rocks
could cause life to thrive, but he thinks it has something to do with
creating new nooks and crannies for life to adapt to in its new
environment.
"Before the breakup you had primitive animals adapted to rough
conditions, so you could say they were prepared for the storm," Schmitz
said.
Schmitz also explained that evolution is very much "give-and-take,"
as radiating into new species requires a figurative kick in the shins.
"If you push an ecosystem too hard, you'll destroy it," he said.
"But for the organisms living on Earth at the time, [the environment]
pushed them to adapt and fill new niches. It's like at the university:
I tell my students all the time that if we don't push you, you don't
evolve."
Whether or not the cosmic smashup ultimately caused life on Earth to
thrive 470 million years ago, the connection between events in space
and life on Earth is intriguing, Schmitz said.
"There's much more to be learned how the history of Earth and its
life is related to the universe," he said. "We're only in the beginning
of exploring that connection."
David Shiga
New Scientist
Mon, 17 Dec 2007 03:35 EST
A comet targeted for a flyby with NASA's Deep Impact spacecraft
cannot be found, forcing mission planners to send the probe to a
different comet. The comet may have evaded telescopes simply because
its predicted orbit was incorrect, or, more intriguingly, it might have
disintegrated completely.
 src="http://www.sott.net/image/image/5202/medium/Epoxi.jpg" /> |
| ©Illustration: JPL/NASA |
| The Epoxi mission was diverted to comet Hartley 2, after its original target comet, 85P/Boethin, could not be found |
The Deep Impact spacecraft completed its main mission in 2005, when it
href="http://space.newscientist.com/article/dn7622--deep-impact-smashes-all-expectations.html">slammed
a metal impactor into comet Tempel 1 and watched the debris fly. After
the successful encounter with Tempel 1, the mission team had hoped to
carry out a second rendezvous, this time with a comet called
85P/Boethin, in late 2008.
But the team now says comet Boethin is nowhere to be found, forcing them to target a different comet called Hartley 2 instead.
Comet Boethin has been spotted only twice, first when it was
discovered during a close approach to the Sun in 1975, and again during
a second close passage in 1986.
The comet was not seen when it was expected to approach the Sun most
recently in 1997. But that is not surprising since it was behind the
glare of the Sun as seen from Earth that time, says Michael A'Hearn of
the University of Maryland in Baltimore, US, chief scientist for the
extended mission.
In October, some of the world's most powerful telescopes, including
the Very Large Telescope (VLT) array in Paranal, Chile, and the Subaru
observatory in Hawaii combed the skies for the comet, but failed to see
it.
Crumble away
It is possible that the comet was destroyed during the 1997 Sun
encounter, disintegrating from the Sun's heat, A'Hearn says. But comet
Boethin never comes closer to the Sun than just beyond Earth's orbit,
making it unlikely to have disintegrated, he says.
"Disappearing in the sense of breaking up and dissipating is actually very rare" for such a comet, he told New Scientist.
"If it disappeared, then that is fascinating in itself - only one other
comet has done that in recent memory." Comet Linear-S4 disintegrated
and disappeared in 2000. A comet called 73P/Schwassmann-Wachmann 3 was
seen fragmenting
in 2006, but it did not crumble away to invisibility.
A somewhat more likely possibility is that the comet broke into a
few large chunks that are still intact but have drifted too far from
the original comet's orbit to have been spotted in searches to date,
A'Hearn says.
Uncertain orbit
However, the most likely explanation of all is that telescopes have
simply been searching in the wrong place, he says. Because the comet
has been briefly spotted only twice, scientists have not been able to
compute its path around the Sun very precisely.
Despite the uncertainty in comet Boethin's orbit, the Deep Impact
team had selected it as a target because it would have been relatively
quick and easy to get to, reducing the cost of the extended mission.
Now, NASA has decided to divert the spacecraft to Hartley 2 instead.
Hartley 2 is about 1.6 kilometres across, about the same size as comet
Boethin. Although it will take longer to get there - the encounter will
not occur until 2010 - Hartley 2 is more active than Boethin was, which
will give the spacecraft more to look at.
The spacecraft turned on its rocket engine for three minutes on 1
November, setting up for a flyby of Earth on 31 December, the first of
three Earth encounters that will use our planet's gravity to adjust the
spacecraft's trajectory for its new mission.
Pummelled by dust
The spacecraft will pass within about 1000 kilometres of the comet.
Trying to get much closer than that would risk the spacecraft getting
pummelled by dust particles, which can do a lot of damage due to their
high speeds, A'Hearn says.
Only a small number of comets have been seen up close. Adding
another to the mix will help scientists understand better which
features tend to be the same and which vary from comet to comet, he
adds.
The Deep Impact spacecraft's extended mission has been named EPOXI. The spacecraft will also use its camera to
href="http://space.newscientist.com/article/dn10417-deep-impacts-blurry-camera-may-study-exoplanets.html">watch stars with so-called
transiting planets - planets known to pass in front of their parent star as seen from Earth, periodically blocking some of the starlight.
The way the starlight varies as the planet moves in front of the
star could lead to the discovery of rings or moons around the known
planets, and possibly result in the discovery of additional planets
with masses as small as three times that of Earth.
Sandia National Laboratories
Tue, 18 Dec 2007 15:02 EST
The stunning amount of forest devastation at Tunguska a century ago
in Siberia may have been caused by an asteroid only a fraction as large
as previously published estimates, Sandia National Laboratories
supercomputer simulations suggest.
"The asteroid that caused the extensive damage was much smaller than
we had thought," says Sandia principal investigator Mark Boslough of
the impact that occurred June 30, 1908. "That such a small
object can do this kind of destruction suggests that smaller asteroids
are something to consider. Their smaller size indicates such collisions
are not as improbable as we had believed."
 src="http://www.sott.net/image/image/5212/medium/mark_nr.jpg" /> |
| ©Randy Montoya |
| INCINERATION POSSIBLE - Fine points of the "fireball" that might be expected from an asteroid exploding in Earth's atmosphere are indicated in a supercomputer simulation devised by a team led by Sandia researcher Mark Boslough. |
Because smaller asteroids approach Earth statistically more
frequently than larger ones, he says, "We should be making more efforts
at detecting the smaller ones than we have till now."
The new simulation - which more closely matches the widely known
facts of destruction than earlier models - shows that the center of
mass of an asteroid exploding above the ground is transported downward
at speeds faster than sound. It takes the form of a high-temperature
jet of expanding gas called a fireball.
This causes stronger blast waves and thermal radiation pulses at the
surface than would be predicted by an explosion limited to the height
at which the blast was initiated.
"Our understanding was oversimplified," says Boslough, "We no longer
have to make the same simplifying assumptions, because present-day
supercomputers allow us to do things with high resolution in 3-D.
Everything gets clearer as you look at things with more refined tools."
Sandia is a National Nuclear Security Administration laboratory.
The new interpretation also accounts for the fact that winds were
amplified above ridgelines where trees tended to be blown down, and
that the forest at the time of the explosion, according to foresters,
was not healthy. Thus previous scientific estimates had overstated the
devastation caused by the asteroid, since topographic and ecologic
factors contributing to the result had not been taken into account.
"There's actually less devastation than previously thought," says
Boslough, "but it was caused by a far smaller asteroid. Unfortunately,
it's not a complete wash in terms of the potential hazard, because
there are more smaller asteroids than larger ones."
Boslough and colleagues achieved fame more than a decade ago by
accurately predicting that that the fireball caused by the intersection
of the comet Shoemaker-Levy 9 with Jupiter would be observable from
Earth.
Simulations show that the material of an incoming asteroid is
compressed by the increasing resistance of Earth's atmosphere. As it
penetrates deeper, the more and more resistant atmospheric wall causes
it to explode as an airburst that precipitates the downward flow of
heated gas.
Because of the additional energy transported toward the surface by
the fireball, what scientists had thought to be an explosion between 10
and 20 megatons was more likely only three to five megatons. The
physical size of the asteroid, says Boslough, depends upon its speed
and whether it is porous or nonporous, icy or waterless, and other
material characteristics.
"Any strategy for defense or deflection should take into
consideration this revised understanding of the mechanism of
explosion," says Boslough.
One of most prominent papers in estimating frequency of impact was
published five years ago in Nature by Sandia researcher Dick Spalding
and his colleagues, from satellite data on explosions in atmosphere.
"They can count those events and estimate frequencies of arrival
through probabilistic arguments," says Boslough.
The work was presented at the American Geophysical Union meeting in
San Francisco on Dec. 11. A paper on the phenomenon, co-authored by
Sandia researcher Dave Crawford and entitled "Low - altitude airbursts
and the impact threat" has been accepted for publication in the
International Journal of Impact Engineering.
The research was paid for by Sandia's Laboratory-Directed Research and Development office.
Laura Knight-Jadczyk
SOTT.NET Book Review
Wed, 19 Dec 2007 08:08 EST
 src="http://www.sott.net/image/image/5232/medium/black_deathbrueghel.jpg" /> |
| ©n/a |
| Medieval depiction of the Black Death |
New Light on the Black Death: The Cosmic Connection by
dendrochronologist Mike Baillie of Queen's
University, Belfast, Ireland.
I just finished reading this one and all I can say is: Wow! This was
an intense book! Not a long one, either - just 208 pages including
appendices. It's tight and economical with no wasted words or idle
rambling around. Every example and temporary diversion is crucial to
the central argument which is - brace yourself for this one - Mike
Baillie (yeah, a real scientist and not a crackpot), is saying that the
Black Death, one of the most deadly pandemics in human history, said to
have killed possibly two thirds of the entire population of Europe, not
to mention millions all over the planet, probably wasn't Bubonic Plague
but was rather Death By Comet(s)!
Oh yeah! That's far out, isn't it?
Maybe not. Baillie has the scientific evidence to support his theory
and his evidence actually supports - and is supported by - what the
people of the time were saying: earthquakes, comets, rains of death and
fire, corrupted atmosphere, and death on a scale that is almost
unimaginable. Most people nowadays are not really aware of what
happened just 660 years ago. (Hmmm... the inquiring mind immediately
wonders what might happen when we hit 666 years after?! That would be
2012...)
Anyway, China, where the Black Death is said to have originated,
lost around half of its entire population (going from around 123
million to around 65 million).
Recent research into European death tolls also suggest a figure of
45% to 50% of the total European population dying during a four-year
period though the figure fluctuated from place to place (which is a
problem as we will see).
In Mediterranean Europe and Italy, the South of France and Spain,
where the plague ran for about four years consecutively, it was
probably closer to 70% to 75% of the total population. (In the USA
today, that would be equivalent to reducing the population from its
current 300 million total to 75 million in less than four years. That
would also amount to having to bury or dispose of around 225 million
corpses!)
In Germany and England it was probably closer to 20%. Northeastern
Germany, Bohemia, Poland and Hungary are believed to have suffered less
for some reason (and there are a few theories which are not entirely
satisfactory).
There are no estimates available for Russia or the Balkans so it
seems that they may have suffered little, if at all. Africa lost
approximately 1/8th of its population (from around 80 million to 70
million). (These figures actually highlight one of the problems that
Baillie brings up: the variability of death rates according to
location.)
Whatever the death rate in any given location, the bottom line is
that the Black Death produced the largest death toll from any known
pandemic in recorded history and, as Baillie points out, nobody really
knows what it was! Oh, of course, for a very long time everybody just
"knew" it was Bubonic plague, so how is it that Baillie questions this
well-established fact? He's not the only one.
In 1984, Graham Twigg published The Black Death: A Biological
Reappraisal,
where he argued that the climate and ecology of Europe and particularly
England made it nearly impossible for rats and fleas to have
transmitted bubonic plague and that it would have been nearly
impossible for Yersinia pestis to have been the causative agent of the
plague, let alone its explosive spread across Europe during the 14th
century. Twigg also demolishes the common theory of entirely pneumonic
spread. He proposes, based on his examination of the evidence and
symptoms, that the Black Death may actually have been an epidemic of
pulmonary anthrax caused by Bacillus anthracis.
Another unhappy camper in the standard model is Gunnar Karlsson who,
in 2000, pointed out that the Black Death killed between half and
two-thirds of the population of Iceland, although there were no rats in
Iceland at this time. (The History of Iceland by Gunnar Karlsson)
Baillie sums up the problem as follows:
The Black Death of 1347 was believed to be the third great outbreak
of bubonic plague; a plague that is traditionally spread by rats and
fleas. The previous instances were the Plague of
Athens
in 430 BC and the plague at the time of Justinian which arrived into
Constantinople in AD 542. The Plague of Athens was described by
Thucydides, while the Justinian plague was described by
Procopius, among others. [...]The plague is supposed to have originated in Central Asia, or
somewhere in Africa, where plague is endemic in some rodent
populations. It is assumed that some environmental stimulus caused
infected rodents to leave their normal habitats and infect rat
populations, and ultimately human populations, in areas where there was
no natural immunity. The mechanism of transfer is believed to have been
infected fleas leaving the bodies of dead rats and moving to human
hosts who were in turn infected by the feeding fleas. It is believed
that trade routes brought the disease to the Black Sea region and from
there to the central Mediterranean by late 1347. It was then introduced
into Europe through northern Italy and southern France. It immediately
started killing people in large numbers spreading overland at about 1.5
km per day. Between January and the summer to autumn of 1348 it had
spread as far as the British Isles, and by 1350 to Scandinavia and
eventually even Iceland. The spread seems to have curled up through
France, across Belgium into Germany and on into central southern
Europe. This first wave burned itself out by 1351, though there was a
second wave in 1361.It is generally believed that the plague hit an already weakened population in Europe. [...]
At its most basic, the problem is with those rats and fleas. For the
conventional wisdom to work there have to be hosts of infected rats and
they have to be moving at alarming speed - you would almost have to
imagine infected rats scuttling every onward (mostly northward)
delivering, as they died, loads of infected fleas. The snags with this
scenario are legion. For example, there are no descriptions of dead
rats lying everywhere (this is explained by suggesting that either the
rats were indoors, or people were so used to dead rats that they were
not worth mentioning; though if they were indoors how did they travel
so fast?) It did not seem to matter whether you were a rural shepherd
or cleric or a town dweller, both were infected. Yet strangely with
this very infectious disease some cities across Europe were spared.
Moreover, these rats must have been happy to move to cool northern
areas even though bubonic plague is a disease that requires relatively
warm temperatures. Then, when there are water barriers, these rats
board ships to keep the momentum going. (Baillie)
Benedictow, an advocate of the rats and fleas scenarios quoted by Baillie, tells us about these amazing critters:
The Black Death's strategic genius made also another masterstroke
that greatly increased the pace of its conquest of the Iberian
peninsula. Shortly after its multiple invasions of important urban
centres along the coast of the Kingdom of Aragon, it performed a
remarkable metastatic leap and arrived triumphantly in the town of
Santiago de Compostela in the very opposite, north-westernmost corner
of the Iberian Peninsula. (Benedictow, O. J. 2004 The Black Death 1346-1353: The
Complete History. The Boydell press, Woodbridge.)
In 2001, epidemiologists Susan Scott and Christopher Duncan from
Liverpool University proposed the theory that the Black Death might
have been caused by an Ebola-like virus, not a bacterium. Their
research and findings are thoroughly documented in Biology of Plagues.
More recently the researchers have published computer modeling
demonstrating how the Black Death has made around 10% of Europeans
resistant to HIV. (Return of the Black Death: The World's Greatest Serial Killer by Susan
Scott, Christopher Duncan and Biology of Plagues: Evidence from
Historical Populations by Susan Scott, Christopher J. Duncan)
In a similar vein, historian Norman F. Cantor, in his 2001 book In the Wake of the Plague,
suggests the Black Death might have been a combination of pandemics
including a form of anthrax and a cattle murrain. He cites many forms
of evidence including: reported disease symptoms not in keeping with
the known effects of either bubonic or pneumonic plague, the discovery
of anthrax spores in a plague pit in Scotland, and the fact that meat
from infected cattle was known to have been sold in many rural English
areas prior to the onset of the plague.
Samuel K. Cohn, quoted extensively by Baillie also rebutted the
theory (and that's really all it is, and a weak theory at that!) that
the Black Death was bubonic plague. In the Encyclopedia of Population, he points
to five major weaknesses in this theory:
- very different transmission speeds - the Black Death was reported
to have spread 385 km in 91 days in 664, compared to 12-15 km a year
for the modern Bubonic Plague, which has the assistance of trains and
cars- difficulties with the attempt to explain the rapid spread of the
Black Death by arguing that it was spread by the rare pneumonic form of
the disease - in fact this form killed less than 0.3% of the infected
population in its worst outbreak in Manchuria in 1911- different seasonality - the modern plague can only be sustained
at temperatures between 50 and 78 °F (10 and 26 °C) and requires high
humidity, while the Black Death occurred even in Norway in the middle
of the winter and in the Mediterranean in the middle of hot dry summers- very different death rates - in several places (including
Florence in 1348) over 75% of the population appears to have died; in
contrast the highest mortality for the modern Bubonic Plague was 3% in
Mumbai in 1903- the cycles and trends of infection were very different between
the diseases - humans did not develop resistance to the modern disease,
but resistance to the Black Death rose sharply, so that eventually it
became mainly a childhood disease
Cohn also points out that while the identification of the disease
as having buboes relies on the account of Boccaccio and others, they
described buboes, abscesses, rashes and carbuncles occurring all over
the body, while the modern disease rarely has more than one bubo, most
commonly in the groin, and is not characterized by abscesses, rashes
and carbuncles which is what Boccaccio described!
The gist of Cohn's argument is that whatever caused the Black
Death, it was not bubonic plague. (See also: Samuel K. Cohn 2002, "The
Black Death: End of the Paradigm." and The Black Death and the Transformation of
the West (European History Series) by David Herlihy and Samuel K., Jr. Cohn)
When one begins to dig into the subject, we find that there was one
study that claimed that tooth pulp tissue from a fourteenth-century
plague cemetery in Montpellier tested positive for molecules associated
with Y. pestis (bubonic plague). Similar findings were reported in a
2007 study, but other studies have not supported these results. In
fact, in September of 2003, a team of researchers from Oxford
University tested 121 teeth from sixty-six skeletons found in
fourteenth-century mass graves. The remains showed no genetic trace of Y. pestis, and the researchers suspect that the Montpellier
study was flawed[
What these studies do not address is the problem that the apparent
means of infection or transmission varied widely, from human-to-human
contact as in Iceland (rare for plague and cutaneous Bacillus
anthracis) to infection in the absence of living or recently-dead
humans, as in Sicily (which speaks against most viruses).
To all the problems with the Bubonic Plague theory cited above, we
have to add what the contemporary writers recorded. Philip Ziegler
collected many of these items in his book The Black Death, though he
dismisses them as "metaphor". We'll be looking at some of them in just a moment.
Mike Baillie didn't start out to write a book about cometary impacts
being implicated in the great Pandemics of the past; he had just
noticed some strange tree ring patterns that happened to coincide with
this historical catastrophe and thought that, perhaps, there was some
sort of environmental downturn that weakened the human population,
making humanity susceptible to bacterial or viral death on a large
scale. But, what he found was a dangling thread that, once he began to
pull on it, unraveled the "accepted wisdom" about the Black Death and
sent him off on a search that led to completely astonishing
conclusions.
As mentioned, the first clue was tree rings - that's natural since
Baillie is a dendrochronologist. He compared these tree rings to dated
ice-core samples that had been analyzed and discovered a very strange
thing: ammonium. There are, as it happens, four occasions in the last
1500 years where scientists can confidently link dated layers of
ammonium in Greenland ice to high-energy atmospheric interactions with
objects coming from space: 539, 626, 1014, and 1908 - the Tunguska event.
In short, there is a connection between ammonium in the ice cores and
extra-terrestrial bombardment of the surface of the earth.
Now notice that the above statement is that there are four events
that can be definitively linked with high-energy interactions; Baillie
presents the research in this book showing that the exact same
signature is present at the time of the Black Death in both the tree
rings and in the ice cores, AND at other times of so-called "plague and
pandemic".
As it happens, the ammonium signal in the ice-cores is directly
connected to an earthquake that occurred on January 25th, 1348 - and
Baillie discovers that there was a 14th century writer who wrote that
the plague was a "corruption of the atmosphere" that came from this
earthquake!
How could a plague come from an earthquake, you ask?
Baillie points out that we don't always know if earthquakes are
caused by tectonic movements; they could be cause by cometary
explosions in the atmosphere or even impacts on the surface of the
earth.
In Rain of Iron and Ice
by John Lewis, Professor of Planetary Sciences at the Lunar and
Planetary Laboratory, Co-director of the NASA/University of Arizona
Space Engineering Research Center, and Commissioner of the Arizona
State Space Commission, tells us that the earth is regularly hit by
extraterrestrial objects and many of the impacting bodies explode in
the atmosphere as happened in Tunguska, leaving no craters or
long-lasting visible evidence of a body from space.
But just because there is no long-lasting evidence doesn't mean
there is no significant effect on the planet and/or its inhabitants!
These impacts or atmospheric explosions may produce earthquakes or
tsunamis without any witnesses being aware of the cause. After all, the
earth is 75% water and any eye-witness to such an event would very
likely be fried and never tell about it, so we really have no way of
knowing if all the earthquakes on our planet are tectonic in nature or
not.
Lewis points out:
In an average year there is one atmospheric explosion with a yield
of 100 kilotons or more. The large majority occur in such remote areas,
or so high in the atmosphere, that they are not observed. Even if
observed, the witnesses may see only a flash of light in the distance,
or hear the 'rumble of distant thunder' coming from the open oceans.
Thus even those that are observed are often not recognized. (Lewis,
Rain of Iron and Ice)
As Baillie points out, Lewis is talking about a "typical" year and
it is obvious, from other studies, that not all years are equal - some
are less typical than others! Baillie writes:
As Lewis pointed out, we know from many strands of evidence broadly
what the impact rate should be over time. The fact that impacts are not
in the historical record [or not admitted or discussed by historians or
archaeologists] is not because none happened. After all, there are
those well-attested crater fields that were formed in the last few
millennia in Estonia, Poland, Germany and Italy - which were not
recorded historically; their existence was deduced from holes in the
ground. So we know the recording mechanism is flawed! What needs to be
added ... is one key piece of intuitive thinking. Here is a quote from
Lewis' Scenario D:(In this scenario) In 1946 a 25,000-metric-ton achondritic fireball
explodes at 4:00 AM local time at a height of 11km above Fergana,
Uzbekistan. The 1-megaton blast damages buildings over an area several
kilometers in diameter, searing the area with intense heat and setting
thousands of fires. The fires burn out of control, killing 4,146. Over
20,000 residents are awakened by the brilliant flash of light and heat
to find their city in flames. An 'earthquake' is reported by the
survivors. Several metric tons of meteorite fragments are mixed in with
the debris of 2000 burned-out and collapsed buildings, where they are
indistinguishable from scorched and blackened fragments of structural
brick and rock. (Lewis quoted by Baillie)
The point of this is that there is almost no way to monitor whether
or not any given disaster/catastrophe is definitively an impact as
opposed to a violent earthquake. The result is that centuries could be
passing, with numerous cometary impacts happening all the time, and no
one suspecting the true hazards from space! As Baillie points out:
there are many earthquakes recorded in history, but NO impacts! And
yet, there is the evidence that the impacts HAVE happened - on the
ground, and in the ice cores. And there is Tunguska.
Reports of the Tunguska event tell us that the ground shook around
the impact/explosion zone for a radius of about 900km. At the time of
any larger impact event, the earthquake would be proportionally more
severe. Any survivors of such an event who are far enough away to
survive, would only have seen a flash, felt a tremor, and heard a loud
rumbling noise. If they were too far away to see the flash, or were
indoors, they would only report an earthquake.
In short, what the work of Lewis brings to the table is the idea
that some well-known historical earthquakes could very well have been
impact events. Baillie mentions that one obvious prospect is the great
Antioch earthquake of AD 526 which was described by John Malalas:
...those caught in the earth beneath the buildings were incinerated
and sparks of fire appeared out of the air and burned everyone they
struck like lightning. The surface of the earth boiled and foundations
of buildings were struck by thunderbolts thrown up by the earthquakes
and were burned to ashes by fire... it was a tremendous and incredible
marvel with fire belching out rain, rain falling from tremendous
furnaces, flames dissolving into showers ... as a result Antioch became
desolate ... in this terror up to 250,000 people perished. (Jeffreys,
E., Jeffreys, M. and Scott, R. 1986, The Chronicle of John Malalas,
Byzantina Australiensia, Australian Assoc. Byzantine Studies 4, Melbourne.)
Baillie also points out that a series of such impacts/overhead
explosions, would more adequately explain the longstanding problem of
the end of the Bronze Age in the Eastern Mediterranean in the 12th
century BC. At that time, many - uncountable - major sites were
destroyed and totally burned and it has all been blamed on those
supernatural "Sea Peoples." If that was the case, if it was invasion
and conquest, there ought to at least be some evidence for that, like
dead warriors or signs of warfare... but for the most part, that is not
the case. There were almost no bodies found, and no precious objects
except those that were hidden away as though someone expected to return
for them, or didn't have time to retrieve them. The people who fled
(extra-terrestrial events often have precursor activities and warnings
because a comet can be observed approaching for some time) were
probably also killed in the act of fleeing and the result was total
abandonment and total destruction of the cities in question.
And the onset of Dark Ages.
So, the possibility that many destructions of the past could have
been related to impact events has never been taken seriously or tested
and this could be a perilous error.
The question that Baillie asks, but never really answers is: What
was it that so successfully stopped people asking why there is a
traditional and deeply ingrained fear of comets in the psyche of
humanity? He points out that, yes, there are people outside of
mainstream academia who ask these questions. But why, against all good
common sense is this subject so widely and systematically ignored,
marginalized and ridiculed?
The odd thing is that, even though Baillie points out that many high-level scientists and government agencies are
taking these things seriously (Lewis, for example), it is still
ignored, marginalized and ridiculed to the general public via the
mainstream media! Baillie writes:
In case readers think this is simply rhetoric, this is as good a
place as any to mention a forthcoming event. On 13 April 2029 an
asteroid named Apophis will pass by the earth at a distance of less
than 50,000km. If you're alive at the time, and it is not cloudy,
you'll be able to see it pass with the naked eye. Apophis is more than
300m in diameter. If, as it passed the earth, it just happens to pass
through a certain narrow window in space, then, in 2036 it will return
and hit the earth (this narrow window is a point where the earth's
gravity would deflect the orbit of Apophis just enough to ensure an
impact in 2036). If Apophis hits the earth the impact will be in the
3000-megaton class. It is entirely reasonable to state that such an
impact, taking place anywhere on the planet, would collapse our current
civilization and return the survivors, metaphorically speaking, to the
Dark Ages (it is believed that in such an event globalised
institutions, such as the financial and insurance markets would
collapse, bringing down the entire interconnected monetary, trade and
transport systems). Impacts from space are not fiction, and it seems
highly likely that quite a number have taken place in the last few
millennia (over and above the small crater-forming examples already
mentioned). It is just that, for some reason, most people who study the
past have chosen to avoid, or ignore, the issue. (Baillie)
Along with the science, Baillie cites contemporary evidence - some
of this evidence has been relegated to "myth" - from around the globe
that indicate that the earth was, indeed, subjected to bombardment from
space during the 14th century and that this may very well have been not
only the cause of the 25 January 1348 earthquake, but also the cause of
the Black Death. Baillie quotes a great selection of material from
contemporary accounts including the work of Ziegler cited above:
Droughts, floods, earthquakes, locusts, subterranean thunder,
unheard of tempests, lightning, sheets of fire, hail stones of
marvelous size, fire from heaven, stinking smoke, corrupted atmosphere,
a vast rain of fire, masses of smoke. (Ziegler)
Ziegler discounts entirely reports of a black comet seen before the
arrival of the epidemic but records: heavy mists and clouds, falling
stars, blasts of hot wind, a column of fire, a ball of fire, a violent
earth tremor, in Italy a crescendo of calamity involving earthquakes,
following which, the plague arrived. (Baillie)
As it happens, in the 1340s there was a veritable rash of earthquakes. In Rosemary Horrox's book,
href="http://www.amazon.com/Black-Death-Manchester-Medieval-Sources/dp/0719034981/ref=pd_bbs_sr_1?
ie=UTF8&s=books&qid=1198072606&sr=1-1">The Black Death,
quoted by Baillie, we find that a contemporary writer in Padua reported
that not only was there a great earthquake on 25 January 1348, but it
was at the twenty-third hour.
In the thirty-first year of Emperoro Lewis, around the feast of the
Conversion of St. Paul (25 January) there was an earthquake throughout
Carinthia and Carniola which was so severe that everyone feared for
their lives. There were repeated shocks, and on one night the earth
shook 20 times. Sixteen cities were destroyed and their inhabitants
killed.... Thirty-six mountain fortresses and their in habitants were
destroyed and it was calculated that more than 40,000 men were
swallowed up or overwhelmed.
(The author goes on to say that he received information from "a
letter of the house of Friesach to the provincial prior of Germany):
It says in the same letter that in this year [1348] fire falling
from heaven consumed the land of the Turks for 16 days; that for a few
days it rained toads and snakes, by which many men were killed: that a
pestilence has gathered strength in many parts of the world. (Horrox)
From Samuel Cohn's book:
... a dragon at Jerusalem like that of Saint George that devoured
all that crossed its path .... A city of 40,000 ... totally demolished
by the fall from heaven of a great quantity of worms, big as a fist
with eight legs, which killed all by their stench and poisonous
vapours. (Cohn)
A story by the Dominican friar Bartolomeo:
... massive rains of worms and serpents in parts of China, which
devoured large numbers of people. Also in those parts fire rained from
Heaven in the form of snow (ash), which burnt mountains, the land, and
men. And from this fire arose a pestilential smoke that killed all who
smelt it within twelve hours, as well as those who only saw the poison
of that pestilential smoke. (Cohn)
Cohn writes:
Nor were such stories merely the introductory grist of naïve
merchants and possibly crazed friars ... [even] ... Petrarch's closes
friend, Louis Sanctus, before embarking on his careful reporting of the
plague... claimed that in September floods of frogs and serpents
throughout India had presaged the coming to Europe in January of the
three pestilential Genoese galleys... [even] ... the English chronicler
Henry Knighton ... [reported how] ... at Naples the whole city was
destroyed by earthquake and tempest. Numerous chroniclers reported
earthquakes around the world, which prefigured the unprecedented
plague. Most narrowed the event to Vespers, 25 January 1348. [...]Of these earthquakes that "destroyed many cities, towns, churches,
monasteries, towers, along with their people and beasts of burden, the
worst hit was Villach in southern Austria. Chroniclers in Italy,
Germany, Austria, Slavonia, and Poland said it was totally submerged by
the quake with one in 10 surviving. (Cohn)
A continental text dated Sunday 27 April 1348 states:
They say that in the three months from 25 January [1348] to the
present day, a total of 62,000 bodies were buried in Avignon. (Horrox)
A German treatise unearthed by Horrox says:
Insofar as the mortality arose from natural causes its immediate
cause was a corrupt and poisonous earthy exhalation, which infected the
air in various parts of the world... I say it was the vapour and
corrupted air which has been vented - or so to speak purged - in the
earthquake that occurred on St. Paul's day [1348], along with the
corrupted air vented in other earthquakes and eruptions, which has
infected the air above the earth and killed people in various parts of
the world. (Horrox)
As Baillie notes, if this oft-cited earthquake was, in reality, the
result of cometary impacts then the corrupted air could be from one or
two causes: high-energy chemical transformations in the atmosphere or
outgassings from the earth itself.
The German Historian, Hecker, informs us:
On the island of Cyprus, the plague from the East had already broken
out; when an earthquake shook the foundations of the island, and was
accompanied by so frightful a hurricane, that the inhabitants... fled
in dismay... The sea overflowed... Before the earthquake, a pestiferous
wind spread so poisonous an odour that many, being overpowered by it,
fell down suddenly and expired in dreadful agonies. ... and as at that
time natural occurrences were transformed into miracles, it was
reported that a fiery meteor, which descended on the earth far in the
East, had destroyed everything within a circumference of more than a
hundred leagues, infecting the air far and wide. (Cohn)
Jon Arrizabalaga compiled a selection of writings in an attempt to
understand what educated people were saying about the Black Death while
it was happening. Regarding the terms used by doctors and other medical
people in 1348 to describe the plague, he writes:
One... Jacme d'Agramaont, discussed it in terms of an "epidemic or
pestilence and mortalities of people" which threatened Lerida from
"some parts and regions neighbouring to us" ... Agramont said nothing
concerning the term epidemia, but he extensively developed what he
meant by pestilencia. He gave this latter term a very peculiar
etymology, in accordance with a from of knowledge established by
Isidore of Seville (570=636) in his Etymologiae, which came to be
widely accepted throughout Europe during the Middle Ages. He split the
term pestilencia up into three syllables, each having a particular
meaning: pes = tempesta: 'storm, tempest'; te = 'temps, time', lencia =
clardat: 'brightness, light'; hence, he concluded, the pestilencia was
'the time of tempest caused by light from the stars.'
As it happens, Isidore of Seville lived not long after another
period of cometary bombardment over Europe which is also evident in the
tree ring and ice core studies. On August 17, 1999, the Knight Ridder
Washington Bureau published an article by Robert S. Boyd entitled:
href="http://abob.libs.uga.edu/bobk/ccc/cc081899.html">Comets may have caused Earth's great empires to fall which included the
following:
Analysis of tree rings shows that at in 540 AD in different parts of
the world the climate changed. Temperatures dropped enough to hinder
the growth of trees as widely dispersed as northern Europe, Siberia,
western North America, and southern South America.A search of historical records and mythical stories pointed to a
disastrous visitation from the sky during the same period, it is
claimed. There was one reference to a "comet in Gaul so vast that the
whole sky seemed on fire" in 540-41.According to legend, King Arthur died around this time, and Celtic
myths associated with Arthur hinted at bright sky Gods and bolts of
fire.In the 530s, an unusual meteor shower was recorded by both
Mediterranean and Chinese observers. Meteors are caused by the fine
dust from comets burning up in the atmosphere. Furthermore, a team of
astronomers from Armagh Observatory in Northern Ireland published
research in 1990 which said the Earth would have been at risk from
cometary bombardment between the years 400 and 600 AD. [...]Famine followed the crop failures, and hard on its heels bubonic plague that swept across Europe in the mid-6th century. [...]
At this time, the Roman emperor Justinian was attempting to
regenerate the decaying Roman empire. But the plan failed in 540 and
was followed by the Dark Ages and the rise of Islam.
There is a large body of material from that period which
consistently points to a "corrupted atmosphere," breathe the air and
you die", and somehow, the ocean was involved as well as earthquakes
and comets and fireballs in the sky. A report of the Medical Faculty of
Paris prepared in October 1348 says:
Another possible cause of corruption, which needs to be borne in
mind, is the escape of the rottenness trapped in the center of the
earth as a result of earthquakes - something that has indeed recently
occurred. (quoted by Baillie)
In short, the French were aware of a series of earthquakes at the
time that may have been caused by cometary impacts. One report of that
period says that an earthquake lasted for six days and another claimed
the period was ten days. Such events could also produce outgassing of
all sorts of unpleasant chemicals which could kill. Consider the
following:
The Lake NYOS Gas Explosion, Cameroon
1986
[...]
Although a sudden outgassing of CO2 had occurred at Lake Monoun in
1984, killing 37 local residents, a similar threat from Lake Nyos was
not anticipated. However, on August 21, 1986, a limnic eruption
occurred at Lake Nyos which triggered the sudden release of about 1.6
million tonnes of CO2. The gas rushed down two nearby valleys,
displacing all the air and suffocating up to 1,800 people within 20 km
of the lake, mostly rural villagers, as well as 3,500 livestock. About
4,000 inhabitants fled the area, and many of these developed
respiratory problems, burns, and paralysis as a result of the gases.It is not known what triggered the catastrophic outgassing. Most
geologists suspect a landslide, but some believe that a small volcanic
eruption may have occurred on the bed of the lake. [...]It is believed that up to a cubic kilometre of gas was released.
Because CO2 is denser than air, the gas flowed off the mountainous
flank in which Lake Nyos rests and down two adjoining valleys in a
layer tens of metres deep, displacing the air and suffocating all the
people and animals before it could dissipate. The normally blue waters
of the lake turned a deep red after the outgassing, due to iron-rich
water from the deep rising to the surface and being oxidised by the
air. The level of the lake dropped by about a metre, representing the
volume of gas released. The outgassing probably also caused an overflow
of the waters of the lake. Trees near the lake were knocked down.
Hmmm... one wonders if similar events could be triggered by
cometary impacts and if outgassing from oceans could be as dangerous
and deadly? One also wonders, considering the fact that trees were
"knocked down," if this outgassing might not have been an impact event?
Baillie takes us through the science with hard numbers and graphs
and shows us how these things were spoken about plainly by those who
experienced the Black Death but, for some reason, modern historians all
think these remarks about rains of fire and death and air that could
kill were all just metaphors for a horrible disease. In the end, it is
the science that must win on this one because totally independent
workers studying comets, tsunami, carbon dioxide, ice cores and tree
rings all observe in their data something very strange happening
globally around the time that the Black Death decimated the human
population of the Earth.
Baillie notes in his closing remarks, worth repeating here:
It is increasingly evident that intellectually the world is divided
into two. There are those who study the past, in the fields of history
and archaeology, and see no evidence for any human populations ever
having been affected by impacts from space. In diametric opposition to
this stance there are those who study the objects that come close to,
and sometimes collide with, this planet. Some serious members of this
latter group have no doubt whatsoever that there must have been
numerous devastating impacts in the last five millennia; the period of
human civilization.
And yet, nobody talks about it.
There really is quite sufficient data presented in Baillie's book to
support the theory that the Black Death was due to an impact by Comet
Debris - similar to the impacts on Jupiter by the fragments of Comet
Shoemaker-Levy back in 1994. As to exactly how these deaths occurred,
there are a number of possibilities: earthquakes, floods (tsunami),
rains of fire, chemicals released by the high-energy explosions in the
atmosphere, including ammonium and hydrogen cyanide, and possibly even
comet born disease pathogens.
If it has happened as often as Baillie suggests, it can happen
again. And if, as we suspect, the Earth is slated for a bombardment in
the not too distant future, it seems that there are more ways to die in
such an event than just getting hit by a comet fragment.
 src="http://www.sott.net/image/image/5231/medium/Black_Death_by_JasonEngle.jpg" /> |
| ©Jason Engle |
| The Black Death: The Legends of Fire Breathing Dragons may have originated from Cometary disasters |
New Light on the Black Death: The Cosmic Connection by
dendrochronologist Mike Baillie of Queen's
University, Belfast, Ireland, published by Tempus, 2006.
Dr Mike Baillie is a Professor Emiritus of Palaeoecology in the
School of Archaeology and Palaeoecology at Queen's University of
Belfast in Northern Ireland.
Baillie is a leading expert in dendrochronology, or dating by
means of tree-rings. In the 1980s, he was instrumental in building a
year-by-year chronology of tree-ring growth reaching 7,400 years into
the past.
Sandia National Laboratories
Mon, 17 Dec 2007 22:04 EST
 src="http://www.sott.net/image/image/5241/medium/fireballsim.jpg" /> |
| INCINERATION POSSIBLE - Fine points of the "fireball" that might be expected from an asteroid exploding in Earth's atmosphere are indicated in a supercomputer simulation devised by a team led by Sandia researcher Mark Boslough. (Photo by Randy Montoya) |
The stunning amount of forest devastation at Tunguska a century ago
in Siberia may have been caused by an asteroid only a fraction as large
as previously published estimates, Sandia National Laboratories
supercomputer simulations suggest.
"The asteroid that caused the extensive damage was much smaller than
we had thought," says Sandia principal investigator Mark Boslough of
the impact that occurred June 30, 1908. "That such a small object can
do this kind of destruction suggests that smaller asteroids are
something to consider. Their smaller size indicates such collisions are
not as improbable as we had believed."
Because smaller asteroids approach Earth statistically more
frequently than larger ones, he says, "We should be making more efforts
at detecting the smaller ones than we have till now."
The new simulation - which more closely matches the widely known
facts of destruction than earlier models - shows that the center of
mass of an asteroid exploding above the ground is transported downward
at speeds faster than sound. It takes the form of a high-temperature
jet of expanding gas called a fireball.
This causes stronger blast waves and thermal radiation pulses at the
surface than would be predicted by an explosion limited to the height
at which the blast was initiated.
"Our understanding was oversimplified," says Boslough, "We no longer
have to make the same simplifying assumptions, because present-day
supercomputers allow us to do things with high resolution in 3-D.
Everything gets clearer as you look at things with more refined tools."
Sandia is a National Nuclear Security Administration laboratory.
The new interpretation also accounts for the fact that winds were
amplified above ridgelines where trees tended to be blown down, and
that the forest at the time of the explosion, according to foresters,
was not healthy. Thus previous scientific estimates had overstated the
devastation caused by the asteroid, since topographic and ecologic
factors contributing to the result had not been taken into account.
"There's actually less devastation than previously thought," says
Boslough, "but it was caused by a far smaller asteroid. Unfortunately,
it's not a complete wash in terms of the potential hazard, because
there are more smaller asteroids than larger ones."
Boslough and colleagues achieved fame more than a decade ago by
accurately predicting that that the fireball caused by the intersection
of the comet Shoemaker-Levy 9 with Jupiter would be observable from
Earth.
Simulations show that the material of an incoming asteroid is
compressed by the increasing resistance of Earth's atmosphere. As it
penetrates deeper, the more and more resistant atmospheric wall causes
it to explode as an airburst that precipitates the downward flow of
heated gas.
Because of the additional energy transported toward the surface by
the fireball, what scientists had thought to be an explosion between 10
and 20 megatons was more likely only three to five megatons. The
physical size of the asteroid, says Boslough, depends upon its speed
and whether it is porous or nonporous, icy or waterless, and other
material characteristics.
"Any strategy for defense or deflection should take into
consideration this revised understanding of the mechanism of
explosion," says Boslough.
One of most prominent papers in estimating frequency of impact was
published five years ago in Nature by Sandia researcher Dick Spalding
and his colleagues, from satellite data on explosions in atmosphere.
"They can count those events and estimate frequencies of arrival
through probabilistic arguments," says Boslough.
The work was presented at the American Geophysical Union meeting in
San Francisco on Dec. 11. A paper on the phenomenon, co-authored by
Sandia researcher Dave Crawford and entitled "Low - altitude airbursts
and the impact threat" has been accepted for publication in the International Journal of Impact Engineering.
The research was paid for by Sandia's Laboratory-Directed Research and Development office.
Movie Clips of the fireball simulations are available:
Movie 1
Movie 2
Movie 3
Movie 4
Movie 5
Movie 6
Movie 7
Movie 8
Charles Q. Choi
Space.com/Yahoo!News
Wed, 19 Dec 2007 07:39 EST
The infamous Tunguska explosion, which
mysteriously leveled an area of Siberian forest nearly the size of
Tokyo a century ago, might have been caused by an impacting asteroid
far smaller than previously thought.
The fact that a relatively small asteroid could still cause
href="http://us.rd.yahoo.com/dailynews/space/sc_space/storytext/smallasteroidsposebignewthreat/25617523/SIG=124jh3u1h/*http://www.space.
com/php/video/player.php?video_id=071218-tunguska" target="_blank">such a massive explosion suggests
"we should be making more efforts at detecting the smaller ones than we
have till now," said researcher Mark Boslough, a physicist at Sandia
National Laboratory in Albuquerque, N.M.
The explosion near the Podkamennaya Tunguska River on June 30, 1908,
flattened some 500,000 acres (2,000 square kilometers) of Siberian
forest. Scientists calculated the Tunguska explosion could have been
roughly as strong as 10 to 20 megatons of TNT - 1,000 times more
powerful than the atom bomb dropped on Hiroshima.
Wild theories have been bandied about for a century regarding what caused the
href="http://us.rd.yahoo.com/dailynews/space/sc_space/storytext/smallasteroidsposebignewthreat/25617523/SIG=12ivkdmkc/*http://www.livesci
ence.com/space/scienceastronomy/070626_st_tunguska_crater.html" target="_blank">Tunguska explosion,
including a UFO crash, antimatter, a black hole and famed inventor
Nikola Tesla's "death ray." In the last decade, researchers have
conjectured the event was triggered by an asteroid exploding in Earth's
atmosphere that was roughly 100 feet wide (30 meters) and 560,000
metric tons in mass - more than 10 times that of the Titanic.
The space rock is thought to have blown up above the surface, only fragments possibly striking the ground.
Now new supercomputer simulations suggest "the asteroid that caused the
href="http://us.rd.yahoo.com/dailynews/space/sc_space/storytext/smallasteroidsposebignewthreat/25617523/SIG=125a3frmd/*http://www.space
.com/php/video/player.php?video_id=071218-Tunguska2" target="_blank">extensive damage
was much smaller than we had thought," Boslough said. Specifically, he
and his colleagues say it would have been a factor of three or four
smaller in mass and perhaps 65 feet (20 meters) in diameter.
The simulations run on Sandia's Red Storm supercomputer - the third fastest in the world - detail how
href="http://us.rd.yahoo.com/dailynews/space/sc_space/storytext/smallasteroidsposebignewthreat/25617523/SIG=12g4rvieb/*http://www.space.
com/php/multimedia/imagegallery/igviewer.php?imgid=286&gid=22" target="_blank">an asteroid
that explodes as it runs into Earth's atmosphere will generate a
supersonic jet of expanding superheated gas. This fireball would have
caused blast waves that were stronger at the surface than previously
thought.
At the same time, previous estimates seem to have overstated the
devastation the event caused. The forest back then was not healthy,
according to foresters, "and it doesn't take as much energy to blow
down a diseased tree than a healthy tree," Boslough said. In addition,
the winds
href="http://us.rd.yahoo.com/dailynews/space/sc_space/storytext/smallasteroidsposebignewthreat/25617523/SIG=12gktev6u/*http://www.space.
com/scienceastronomy/planetearth/tunguska_mystery_011031.html" target="_blank">from the explosion
would naturally get amplified above ridgelines, making the explosion
seem more powerful than it actually was. What scientists had thought to
be an explosion between 10 and 20 megatons was more likely only three
to five megatons, he explained.
All in all, the researchers suggest that smaller asteroids
may pose a greater danger than previously believed. Moreover, "there
are a lot more objects that size," Boslough told SPACE.com.
NASA Ames Research Center planetary scientist and astrobiologist David Morrison, who did not participate in this study, said, "If
he's right, we can expect more Tunguska-sized explosions - perhaps
every couple of centuries instead of every millennia or two."
He added, "It raises the bar in the long term - ultimately, we'd like
to have a survey system that can detect things this small."
Boslough and his colleagues detailed their findings at the American
Geophysical Union meeting in San Francisco on Dec. 11. A paper on the
phenomenon has been accepted for publication in the International Journal of Impact Engineering.
Comment: Actually
it appears that small asteroids or comets hit the earth far more often
than thought or reported. Read the latest SOTT focus: New Light on the Black Death: The Cosmic Connection to get the idea...
Karen Hopkin
Scientific American
Thu, 20 Dec 2007 15:33 EST
If you woke up this morning and the newspaper headline screamed
Meteor Headed for Earth, you'd think: That's not good. And you'd
probably be right. But sometimes a little cosmic bombardment can be
just what the doctor ordered. In a study published online in the
journal Nature Geoscience, researchers in Sweden say that 470 million
years ago, meteor showers might have boosted our biodiversity.
The scientists were studying rocks from China and Scandinavia. And
they were looking for two things. First, they were counting the number
of different clam-like species they could find. Second, they were
searching for chemicals that were carried here by meteorites -
extraterrestrial chromite, stuff like that.
They found that a huge burst of diversification coincides exactly
with a time when meteors a mile wide were raining down on the planet.
But wait. Didn't an asteroid wipe out the dinosaurs? Well, yes, but
without all those earlier impacts promoting diversity, maybe there
wouldn't have been any dinosaurs in the first place. And if a meteor
hadn't then slammed the dinos, mammals like us might never have made
the scene. So when it comes to space rocks, one man's ceiling is
another man's flora...and fauna.
John Johnson Jr.
Los Angeles Times
Thu, 20 Dec 2007 12:20 EST
Talk about your cosmic pileups.
An asteroid similar to the one that flattened forests in Siberia in
1908 could plow into Mars sometime in the next few weeks, scientists
said.
Researchers attached to NASA's Near-Earth Objects Program, who like
to call themselves the Solar System Defense Team, have been tracking
the asteroid for days.
The scientists, based at the Jet Propulsion Laboratory in La Cañada
Flintridge, put the chances that it will hit the Red Planet at about 1
in 300. That's better odds than any known asteroid has ever had of
hitting Earth, except for the Siberian strike, the scientists said.
The unnamed asteroid is about 160 feet across, which puts it in the
range of the famous Siberian rock. The largest impact event in recent
history, that explosion felled 80 million trees over an area of 830
square miles.
Concerns about another strike on Earth led to the creation of the
Near-Earth Objects Program and the pursuit of research into possible
ways of deflecting a killer asteroid.
Scientists say it's unclear what the effects of such an impact on
Mars would be. The Martian atmosphere is so thin that an asteroid would
likely plummet all the way to the surface instead of breaking up above
ground, as happened in the Siberian event.
Once it hit, it would probably create a large crater and send plumes
of dust high into the atmosphere, scientists said. Depending on where
it hit, the plume could be visible through telescopes on Earth.
The Mars Reconnaissance Orbiter, which is currently mapping the
planet, would have a front-row seat. NASA's two JPL-built rovers,
Opportunity and Spirit, might also be able to take pictures from the
ground of the impact's effects.
spaceweather.com
Fri, 21 Dec 2007 00:28 EST
Comet 8P/Tuttle is coming and it is bringing a meteor shower with
it. "We could be in for a Merry surprise on Dec. 22nd when Earth passes
through a trail of comet dust," says astronomer Peter Jenniskens of the
SETI Institute.
Previous returns of Comet Tuttle to the inner solar system have been
attended by outbursts of meteors, most recently in 1980 and 1994.
During those flurries, dozens of meteors per hour streamed from the
constellation Ursa Minor--hence the name of the shower, "the Ursids."
 src="http://www.sott.net/image/image/5272/medium/Chris-Schur1_strip.jpg" /> |
| ©Chris Schur |
| Comet 8P/Tuttle photographed Dec. 2nd by Chris Schur of Payson, AZ. The 7th magnitude comet is visible through binoculars in the constellation Cassiopeia. |
Although Ursids have a reputation for being faint, "we are not
certain about this," says Jenniskens. "Because winter weather keeps
many observers indoors, Ursid outbursts have never been widely observed
and they may contain a fair number of bright meteors. We have a lot to
learn." That's why he hopes sky watchers will keep an eye on the
northern sky this weekend; Ursid meteors emerge not far from the north
star, Polaris.
According to models by Jenniskens and colleagues, the peak will
occur between 2100 and 2200 UT (4-5 pm EST) on Dec. 22nd with meteors
visible as much as four hours before and after that time. Anything
could happen, from a dud to a blast. Bundle up and look!
RIA Novosti
Fri, 21 Dec 2007 12:48 EST
An asteroid, which is believed to be on a collision course with
Mars, will not affect the Earth if it hits the 'Red' planet in January
2008, a Russian Academy of Science spokesman said on Friday.
Sergei Smirnov said the asteroid, which is traveling at 8 miles per second, was discovered in November by American scientists.
He said the explosion could be on a scale equal to the Tunguska
event, when a meteorite, which crashed into central Siberia in 1908
caused destruction on a nuclear scale. The enigma still thrills
scientists all over the world.
"It will not influence the Earth in any way," Smirnov said.
The scientist said that if the collision takes place, it will not be
visible without high-definition telescopes, but would still provide
valuable scientific data: "The object is sure to change its flight
path, and this will considerably enrich our knowledge of the mass and
density of asteroids."
He also said a large asteroid was expected to pass near Earth in
2028 which could cause a major disaster if it collides with the planet.
Alicia Chang
Associated Press
Sat, 22 Dec 2007 10:08 EST
LOS ANGELES - Mars could be in for an
asteroid hit. A newly discovered hunk of space rock has a 1 in 75
chance of slamming into the Red Planet on Jan. 30, scientists said
Thursday.
"These odds are extremely unusual. We frequently work with really
long odds when we track ... threatening asteroids," said Steve Chesley,
an astronomer with the Near Earth Object Program at NASA's Jet
Propulsion Laboratory.
The asteroid, known as 2007 WD5, was discovered in late November and
is similar in size to an object that hit remote central Siberia in
1908, unleashing energy equivalent to a 15-megaton nuclear bomb and
wiping out 60 million trees.
Scientists tracking the asteroid, currently halfway between Earth
and Mars, initially put the odds of impact at 1 in 350 but increased
the chances this week. Scientists expect the odds to diminish again
early next month after getting new observations of the asteroid's
orbit, Chesley said.
"We know that it's going to fly by Mars and most likely going to miss, but there's a possibility of an impact," he said.
If the asteroid does smash into Mars, it will probably hit near the
equator close to where the rover Opportunity has been exploring the
Martian plains since 2004. The robot is not in danger because it lies
outside the impact zone. Speeding at 8 miles a second, a collision
would carve a hole the size of the famed Meteor Crater in Arizona.
In 1994, fragments of the comet Shoemaker-Levy 9 smacked into
Jupiter, creating a series of overlapping fireballs in space.
Astronomers have yet to witness an asteroid impact with another planet.
"Unlike an Earth impact, we're not afraid, but we're excited," Chesley said.
Comment: Not afraid but excited??? Are they nuts?
Brian Handwerk
National Geographic News
Fri, 21 Dec 2007 18:33 EST
A huge explosion that devastated a swath of Siberia a century ago
was caused by an asteroid that was much smaller than had previously
been believed, according to new research.
The blast produced an enormous fireball over the Tunguska region of
northwestern Russia in June 1908 (see map). The so-called Tunguska
event leveled trees up to 10 miles (16 kilometers) away.
New supercomputer models of the event show that the devastation may
have been the result of a surprisingly small asteroid that never hit
the ground.
Because smaller asteroids approach Earth's orbit more often than
larger ones, the discovery could also mean that Earth is at increased
risk of asteroid impacts.
"I'm not sure it puts it into a whole new class of risk," said study
author Mark Boslough, a physicist at Sandia National Nuclear Security
Administration laboratory in Albuquerque, New Mexico.
"But there's so much uncertainty in terms of knowing if there's one
million or ten million of these things out there of a given size in
Earth-crossing orbits."
Asteroid the Size of the White House
The Tunguska explosion had previously been estimated at 10 to 20
megatons, but Boslough suggests it was three to five megatons - still
hundreds of times as powerful as the atomic bomb dropped on Hiroshima
in 1945.
The incoming asteroid, moving at some 40 to 60 times the speed of
sound, had roughly the same mass as a solid rock the size of the White
House, the new study found.
This mass is what helped produce such widespread destruction from a relatively small package, Boslough explained.
As the asteroid streaked toward Earth's surface, growing resistance
from the atmosphere compressed the rocky object until its kinetic
energy was converted to heat, causing it to explode into vapor with
tremendous violence.
"Unlike a nuclear bomb, which doesn't have a lot of mass, this has a
lot of mass which carries all that explosive energy downward toward the
surface," Boslough said.
spaceweather.com
Mon, 24 Dec 2007 19:00 EST
Mark your calendar: On Jan. 29, 2008, one night before a
Tunguska-class (50m-wide) asteroid threatens to strike Mars, an even
larger asteroid will fly past our own planet.
At closest approach, 2007 TU24 will be 1.4 lunar distances from Earth. There's no danger of a collision, but the
400m-wide space rock will be close enough to photograph through backyard telescopes as it speeds through the
constellation Cassiopeia glowing like a 10th magnitude star.
Michael Goodspeed
thunderbolts.info
Fri, 21 Dec 2007 08:13 EST
For several weeks in the fall of 2007,
amateur astronomers and sky watchers around the world were entranced by
the mysterious, energetic display of Comet Holmes 17P. The Internet
still abounds with exotic theories about the comet's nature -- some
have claimed it is the "Blue Kachina" foretold in Hopi Prophecy, others
assert that the secret government shot it with a nuclear missile, and
still others say its nucleus is acquiring mass and turning into a
PLANET.
Garish and unfounded speculations aside, it is interesting that
Comet Holmes, while providing a remarkable cometary "light show" and
inciting great interest, never appeared to the naked eye as more than a
tiny, luminous "fluff ball" of light. Certainly, without the aid of
telescopes and space satellites, its unremarkable glow amongst a vast
network of stars and planets would not have captured the average
person's attention. Nor would anyone observing it have had any reason
to feel terror.
But according to the ancient record, comets have long aroused terror
in human beings, and this fear has clearly persisted into modern times.
Even the astronomical mainstream recognizes that comets have
historically been viewed as portents of destruction. The NASA report "
href="http://www.nasa.gov/mission_pages/deepimpact/media/f_ancient.html" target="_blank">Comets in Ancient Cultures"
observes: "Comets have inspired dread, fear, and awe in many different
cultures and societies around the world and throughout time. They have
been branded with such titles as 'the Harbinger of Doom' and
target="_blank">'the Menace of the Universe.'"
In fact, increasing numbers of scientists may be coming to see that
the global theme of the Doomsday comet is not a figment of human
imagination, but a universal memory yet to be deciphered. The recent
Discover Magazine article "Did a Comet
Cause the Great Flood?"
discusses the research of Bruce Masse, an environmental archaeologist
at Los Alamos National Laboratory. Masse says of ancient petroglyphs
depicting coiling serpents, "You can't tell me that isn't a comet."
Masse concludes that, perhaps 5,000 years ago, a body three-miles wide
smashed into the ocean off the coast of Madagascar. A watery cataclysm
ensued, killing roughly eighty percent of the world's population.
But of course, this is not a new idea. In the 17th century, the
English theologian and mathematician William Whiston and many of his
followers had already linked the Biblical deluge to the arrival of a
comet. A poignant illustration of this connection is the 1840 painting
by John Martin, "The Eve of the Deluge." It depicts onlookers observing
the arrival of a comet, in advance of the Great Flood.
While Masse's theory is surely a step in the right direction, it
must ultimately fail, because it does not confront the heart of the
ancient message. This message can become comprehensible only when
investigators are willing to consider the details provided by the
ancient witnesses themselves -- even when these details are
uncomfortable to modern science. The evidence must not be examined
selectively. Myth counts as evidence when widely separated cultures say
precisely the same thing. And if they say the same things on a broad
range of details, it then becomes clear that the evidence could not
exist without the shared experience that provoked it.
 src="http://www.sott.net/image/image/5387/medium/PICTURE_1.jpg" /> |
| ©Unknown |
| The famous Chinese dragon was characterized by flaming, lightning-like emanations. |
For example, when Masse points to a serpent pictograph and insists
it is a comet, that itself is not persuasive at all (and when has an
observed comet in modern times ever produced a full spiral?) It is the
complete story of the cosmic serpent, reconstructed from the points of
agreement from far-flung cultures around the world, that definitively
establishes the serpent as a comet image -- from the Egyptian Apep to
the Babylonian Tiamat, from the Norse Midgard serpent to the Aztec
"Fire Serpent" Xiuhcoatl. But mainstream science has not yet shown
either the courage or openness of mind necessary to see this story
without ideological prejudice. The truth of the matter is that the lens
through which mainstream astronomers and archaeologists consider
ancient testimony cannot fail to distort the message.
Astronomers and astrophysicists today still view comets as icy
bodies moving through electrically neutral space. To hold to this
position, they have steadfastly ignored or dismissed the overwhelming
evidence for an electric comet model. And in doing so, they have failed
resoundingly to anticipate the accumulating surprises, many of which
were predicted by Electric Universe proponent Wallace Thornhill and his
colleagues. These surprises include:
Highly energetic supersonic jets exploding from comets' nuclei; the
inexplicable confinement of these jets into narrow filaments, spanning
great distances, up to MILLIONS of miles, defying the behavior of
neutral gases in a vacuum; jets occurring on the dark sides of comet
nuclei; comet surfaces with sharply carved relief -- the exact opposite
of what astronomers expected under the "dirty snowball" model;
unexpectedly high temperatures and X-ray emissions from cometary comas;
a short supply or complete absence of water and other volatiles on
comets' nuclei; mounting evidence for the production of the radical OH
in cometary comas, due to charge exchange with the Sun (the process
that misled astronomers into thinking they were seeing evidence of
water removed from the surface.); mineral particles that can only be
formed under extremely high temperatures -- the last thing one would
expect from a chunk of dirty ice arriving from the outermost reaches of
the solar system; comets flaring up while in "deep freeze," beyond the
orbit of Saturn; comets disintegrating many millions of miles from the
Sun; comet dust particles more finely and evenly divided than is
plausible for sublimating "dirty ices"; ejection of larger particles
and "gravel" that was never anticipated under the idea that comets
accreted from primordial clouds of ice, gas, and dust; the unexplained
ability of a relatively minuscule comet nucleus to hold in place a
highly spherical coma, up to millions of miles in diamater, against the
force of the solar wind. (For background on the electric comet, click
here)
So we must now ask if the avalanche of recent comet discoveries,
ranging from "surprising" to "astonishing," can help us to understand
the comet-like "dragon" of world mythology?
 src="http://www.sott.net/image/image/5388/medium/PICTURE_2.jpg" /> |
| ©Unknown |
| Enhanced image of comet Hale-Bopp, 1997 |
Without question, the dragon is virtually always connected to
undeniably ELECTRICAL events in the sky. In its attack, lightning and
thunder shake the earth. The ancient Anzu epic from Mesopotomia,
depicting the fiery battle of the dragon and the god Ninurta, states,
"Clouds of death rained down, an arrow flashed lightning. 'Wizzed' the
battle force roared between them." In Hesiod's well-known account of
the dragon Typhon's attack, the earth "groaned" beneath the god Zeus,
"and the heat and blaze from both of them were on the dark-faced sea,
from the thunder and lightning of Zeus and from the flame of the
monster, from his flaming bolts, and from the scorch and breath of his
storm winds."
The Sumerian texts describe the goddess Inanna as a blazing,
destructive celestial force: "Like a dragon you have deposited venom on
the land...raining the fanned fire down upon the nation...With a
roaring storm you roar...devastatrix of the lands...Mankind comes
before you in fear and trembling at your tempestuous radiance.
The Babylonian texts depict the goddess Ishtar in her terrible
aspect: "...shining torch of heaven and earth...furious irresistible
onslaught... I rain down like flames..."
Identical imagery occurs in Egyptian texts. The goddess Sekhmet
becomes the Uraeus serpent raging in the sky: "A flame of fire in her
tempest...the fear of me is in their hearts...the awe of me is in their
hearts...No one at all can approach her...The streams behind her are
flames of fire."
These are just a few instances -- out of hundreds -- pointing to the
electrical properties of the cosmic serpent or dragon. If astronomers,
scientists, and archaeologists are truly interested in human memories
of cometary catastrophe, it is intellectually indefensible to ignore
the overwhelming consensus of the testimony. And this consensus leads
inexorably to decades of evidence from plasma experiments (a field
largely ignored by mainstream astronomers).
 src="http://www.sott.net/image/image/5389/medium/Picture_4.jpg" /> |
| ©Unknown |
| Left: An electric spark in a laboratory; Right: Enigmatic petroglyph on cave wall in Chaco canyon in Mexico. |
Electrified plasma -- a medium defined by the presence of charged
particles -- will naturally generate filamentary, twisted, spiraling,
and life-like structure. This characteristic of electric currents is
also seen in the so-called "magnetic ropes" recently observed by the
THEMIS spacecraft connecting the Sun and the earth (see
target="_blank">The Electric Sun/Earth Connection).
The dragon's effusive feathers, long-flowing beard, streaming mane or
hair, fiery breath and "lightning" like emanations -- all ancient
hieroglyphs for the comet -- are the well-documented characteristics of
plasma discharge. In its electric displays, an energetic comet gives us
the perfect corollary to the cosmic dragon.
But if we are permitted to draw conclusions from the ancient
testimony, the tale of the Doomsday comet surely does not end with the
cosmic serpent/dragon. An abundance of testimony reveals, for example,
an inseparable connection of the attacking serpent or dragon with the
"terrible aspect" of the mother goddess, precisely as indicated by more
than one of the quotes above. This goddess figure stands at the heart
of the ancient cultures -- an object of both reverence and terror. And
in fact, innumerable goddesses acquire a comet-like appearance --
wildly disheveled hair, flaming countenance, accompanied by chaotic
hordes or clouds of chaos, threatening to destroy the world. The moment
one accepts the compelling memories of a serpent or dragon's assault,
it is no longer reasonable to exclude the equally compelling ancient
profiles of the mother goddess. As we shall report in the conclusion of
this piece, the ancients' story of the Doomsday comet, when fully
appreciated, will change our view of human history, and alter the
course of science as well.
Astrobiology Magazine
Tue, 25 Dec 2007 16:45 EST
 src="http://www.sott.net/image/image/5394/medium/asteroid_impact.jpg" /> |
| ©Unknown |
Astrobiology Magazine is looking back over 2007, highlighting
the Top 10 astrobiology stories of the year. At number 9 is a story
about a breakup event in the main asteroid belt. This event produced
the impactor that hit Earth 65 million years ago, ending the age of the
dinosaurs and having a profound effect on the evolution of life as we
know it. (This story was originally published on September 8, 2007.)
The impactor believed to have wiped out the dinosaurs and other life
forms on Earth some 65 million years ago has been traced back to a
breakup event in the main asteroid belt. The finding provides insights
into one of the most important extinction events in Earth's history.
Known as the Cretaceous-Tertiary (K-T) extinction, this impact event
signaled a dramatic change in the evolutionary history of Earth. Understanding
the origins and effects of this event can not only teach us about the
past, but can also help us understand how future impacts could alter
our planet's global biosphere.
A joint U.S.-Czech team from Southwest Research Institute (SwRI) and
Charles University in Prague suggests that the parent object of
asteroid (298) Baptistina disrupted when it was hit by another large
asteroid, creating numerous large fragments that would later create the
Chicxulub crater on the Yucatan Peninsula as well as the prominent
Tycho crater found on the Moon. The team of researchers, including Dr.
William Bottke (SwRI), Dr. David Vokrouhlicky (Charles University,
Prague) and Dr. David Nesvorny (SwRI), combined observations with
several different numerical simulations to investigate the Baptistina
disruption event and its aftermath. A particular focus of their work
was how Baptistina fragments affected the Earth and Moon.
 src="http://www.sott.net/image/image/5396/medium/asteroid_Baptistina.jpg" /> |
| ©Southwest Research Institute |
| The new study suggests that the parent object of asteroid (298) Baptistina was hit by another large asteroid, creating numerous large fragments that would later create the Chicxulub crater on the Yucatan Peninsula as well as the prominent Tycho crater found on the Moon. |
At approximately 170 kilometers in diameter and having
characteristics similar to carbonaceous chondrite meteorites, the
Baptistina parent body resided in the innermost region of the asteroid
belt when it was hit by another asteroid estimated to be 60 kilometers
in diameter. This catastrophic impact produced what is now known as the
Baptistina asteroid family, a cluster of asteroid fragments with
similar orbits. According to the team's modeling work, this family
originally included approximately 300 bodies larger than 10 kilometers
and 140,000 bodies larger than 1 kilometer.
Once created, the newly formed fragments' orbits began to slowly
evolve due to thermal forces produced when they absorbed sunlight and
re-radiated the energy away as heat. According to Bottke, "By carefully
modeling these effects and the distance traveled by different-sized
fragments from the location of the original collision, we determined
that the Baptistina breakup took place 160 million years ago, give or
take 20 million years."
The gradual spreading of the family caused many fragments to drift
into a nearby "dynamical superhighway" where they could escape the main
asteroid belt and be delivered to orbits that cross Earth's path. The
team's computations suggest that about 20 percent of the surviving
multi-kilometer- sized fragments in the Baptistina family were lost in
this fashion, with about 2 percent of those objects going on to strike
the Earth, a pronounced increase in the number of large asteroids
striking Earth.
Support for these conclusions comes from the impact history
of the Earth and Moon, both of which show evidence of a two-fold
increase in the formation rate of large craters over the last 100 to
150 million years. As described by Nesvorny, "The Baptistina
bombardment produced a prolonged surge in the impact flux that peaked
roughly 100 million years ago. This matches up pretty well with what is
known about the impact record."
Bottke adds, "We are in the tail end of this shower now. Our
simulations suggest that about 20 percent of the present-day,
near-Earth asteroid population can be traced back to the Baptistina
family."
The team then investigated the origins of the 180 kilometer diameter
Chicxulub crater, which has been strongly linked to the extinction of
the dinosaurs 65 million years ago. Studies of sediment samples and a
meteorite from this time period indicate that the Chicxulub impactor
had a carbonaceous chondrite composition much like the well-known
primitive meteorite Murchison. This composition is enough to rule out
many potential impactors but not those from the Baptistina family.
Using this information in their simulations, the team found a 90
percent probability that the object that formed the Chicxulub crater
was a refugee from the Baptistina family.
 src="http://www.sott.net/image/image/5395/medium/Chicxulub_impact_crater.jpg" /> |
| ©NASA |
| Artist's depiction of the Chicxulub impact crater. The total number today of objects a kilometer in diameter or larger, a size that could cause a similar global catastrophe upon Earth impact, is now estimated to range between 900 and 1,230. |
These simulations also showed there was a 70 percent probability
that the lunar crater Tycho, an 85 kilometer crater that formed 108
million years ago, was also produced by a large Baptistina fragment.
Tycho is notable for its large size, young age and its prominent rays
that extend as far as 1,500 kilometers across the Moon. Vokrouhlicky
says, "The probability is smaller than in the case of the Chicxulub
crater because nothing is yet known about the nature of the Tycho
impactor."
This study demonstrates that the collisional and dynamical evolution
the main asteroid belt may have significant implications for
understanding the geological and biological history of Earth.
As Bottke says, "It is likely that more breakup events in the
asteroid belt are connected in some fashion to events on the Earth,
Moon and other planets. The hunt is on!"
The article, "An asteroid breakup 160 Myr ago as the probable source
of the K/T impactor," was published in the Sept. 6 issue of Nature.
The NASA Origins of Solar Systems, Planetary Geology and Geophysics,
and Near-Earth Objects Observations programs funded Bottke's and
Nesvorny's research; Vokrouhlicky was funded by the Grant Agency of the
Czech Republic.
Associated Press
Tue, 25 Dec 2007 16:25 EST
Could it have been Rudolph's nose, gleaming brightly? Or maybe just a meteorite in the making?
All across Central last night, there were reports of a fireball seen streaking to the ground.
Keith Clinton, who lives east of Bend says he saw a "large, bright
green fireball descend out of the cloudless sky east of Bend."
Clinton says the fireball turned yellow and exploded about 10 degrees above the horizon, breaking into several pieces as it did.
Meanwhile, near Redmond, Spencer Krueger reported that his wife had seen a "fist-sized flaming orange ball with a tail."
And someone near Prineville called the Crook County sheriff's office to report a meteorite that had come crashing to the ground.
Authorities checked with the Redmond Airport to see if any small
planes had gone off radar screens or gone missing, but nothing of the
sort was reported.
KRNV
Tue, 25 Dec 2007 16:29 EST
Officials are trying to determine what people saw streaking across the sky last evening above Spanish Springs north of Reno.
Washoe County sheriff's deputies and search and rescue team members think they may be looking for a meteorite.
A caller told the sheriff's office of seeing a bright red, blue and
yellow light falling from the sky north of Winnemucca Ranch Road.
Off-duty search and rescue people in the area saw the same thing and began looking for a possible meteorite.
Tammy Plotner
universetoday.com
Fri, 28 Dec 2007 21:50 EST
Beginning each New Year and lasting for
nearly a week, the Quadrantid Meteor Shower sparkles across the night
sky for nearly all viewers around the world.
Its radiant belongs to an extinct constellation once known as
Quadran Muralis, but any meteors will seem to come from the general
direction of bright Arcturus and Boötes.
 src="http://www.sott.net/image/image/5437/medium/quads.thumbnail.gif" /> |
| ©Unknown |
This is a very narrow stream, which may have once belonged to a
portion of the Aquarids, but recent scientific data points to a what
may have been a cosmic collision.
According the most recent data, the Quandrantid meteors may have
been formed about five centuries ago when a near-Earth asteroid named
2003 EH1 and a comet smashed into one another. Historic records from
ancient China put comet C/1490 Y1 in the path of probability. As
Jupiter's gravity continues to perturb the stream, another 400 years
may mean this shower will become as extinct as the constellation for
which it was once known... But NASA scientists and astronomers are
taking to the skies to study the event.
A Gulfstream V aircraft will fly scientists and their instruments
for 10 continuous hours over the Arctic to observe and record meteor
activity. From above the Earth, the stream can be studied without light
pollution and clouds to determine when the activity peaks and how the
stream is dispersed. "We will fly to the North Pole and back to
compensate for Earth's rotation and to keep the stream in view
throughout the flight," said Peter Jenniskens, a principal investigator
at NASA's Ames Research Center.
According to NASA, scientists believe this could be the most
brilliant meteor shower in 2008 with over 100 visible meteors per hour
at its peak. Best viewing times with the highest meteor rates are
expected to be in either the late evening of Jan. 3 over Europe and
western Asia or the early morning of Jan. 4 over the eastern United
States. For the USA: 6pm - 2am (Pacific Time) on Jan. 3 and 4, 2008.
For Northern Europe: 2am - 10am (London) on Jan. 4, 2008. For Northern
Asia: 11am - 7pm (Tokyo) on Jan. 4, 2008. For almost of us, this means
bundling up against the cold and battling the remnants of the waning
Moon... But the sight of even one "shooting star" can make the trip
worthwhile!
Will the Quadrantid Meteor Shower live up to its expectations? No one knows for sure... But we'll be watching!
Leonard David
Live Science
Sat, 29 Dec 2007 16:56 EST
The chance that a rogue mini-world - asteroid 2007 WD5 - will smack
into Mars on January 30th has increased from 1.3 percent to 3.9 percent.
That's the new estimation from officials at the Near Earth Object
Program at the Jet Propulsion Laboratory (JPL), stemming from several
sky watching teams in Alaska, New Mexico, and in Arizona.
"The impact probability resulting from the recent orbit refinement
has increased to a surprising 3.9 percent...about 1 in 25 odds,"
explain JPL's Near Earth Object Program website, updated today
regarding the asteroid meets Mars altercation.
Still, there remains an uncertainty, although a Mars impact is still
possible. However, the most likely scenario in the weeks to come is
that more observations of the asteroid will allow that uncertainty to
shrink - so that a Mars impact is definitely ruled out.
The JPL website notes that, in the unlikely event of an impact, the
head-on collision would take place on January 30th at 2:55 a.m. Pacific
Standard Time, with an uncertainty of a few minutes.
Nothing to set your watch by...but a big event in our time.
Charles Q. Choi
Space.com
Sat, 29 Dec 2007 17:04 EST
For millennia, comets were believed to be
omens of doom. Instead, solving the mysteries regarding these "dirty
snowballs" could help reveal the part they played in the birth of life
on Earth, as well as secrets concerning the rest of the galaxy.
Did comets help create Earth's seas?
For years scientists thought comets slamming against the newborn Earth
href="http://www.space.com/scienceastronomy/060324_mainbeltcomets_water.html">helped deliver water
to a once dry planet. But roughly a decade ago this view was shaken by
the discovery that the water in comets and Earth's oceans did not match
up in terms of hydrogen isotopes.
Calculations then showed it was highly improbable that enough icy
rocks from the suspected homes of comets - the Kuiper belt past Neptune
and the Oort cloud past that - could have collided with Earth to supply
its oceans.
In the last two years, however, researchers have discovered comets in the outer part of the asteroid belt. These "
href="http://www.space.com/scienceastronomy/060324_mainbeltcomets_water.html">main-belt comets"
may have the right levels of hydrogen isotopes, and are perhaps close
enough to Earth to have realistically brought us the seas that life
emerged from.
"No one knows for certain yet where Earth's oceans came from," said
University of Hawaii astrophysicist David Jewitt. "Earth's oceans are
likely a mixture of water from all sorts of places, but the main-belt
comets are very likely one of them."
Where do comets come from?
The suspected homes of comets include the Oort cloud, the Kuiper belt and now the asteroid belt. But are there more
href="http://www.space.com/php/multimedia/imagegallery/igviewer.php?imgid=334&gid=25&index=0">reservoirs of comets yet
to be found?
The Oort cloud is a theoretical cloud of icy rocks roughly 4.6
trillion miles (7.5 trillion kilometers) from the sun thought to be the
source of long-period comets - that is, ones that take more than a few
centuries to complete their orbits. It was once thought the original
home of short-period comets as well, until calculations suggested that
was impossible.
About 20 years ago, the Kuiper belt roughly 4.6 billion miles (7.5
billion kilometers) from the sun was then proposed to be the home of
short-period comets. "But measurements taken in the last few years
raise some doubts about that," Jewitt explained. "Maybe there are other
reservoirs of comets yet to be discovered."
Secrets regarding the birth of the solar system?
Comets were long thought to be primordial relics, pristine leftovers
from the protoplanetary disk that once surrounded the newborn sun. As
such, it was supposed they might hold secrets untouched for billions of
years regarding the birth of our solar system.
Increasingly, however, it looks as if the comets we see are anything
but unspoiled. Instead, "there is good evidence that many of them are
nearly burned-out hulks, with neither the
size, mass, shape nor spin they might have had before entering the solar system," Jewitt said.
Still, "since comets are icy, they're not entirely cooked, and we
may learn a lot regarding the formation of the solar system from
chemicals trapped in their ice," he added.
Comets so close to the sun?
The main-belt comets are themselves a mystery.
Until their discovery, researchers had largely supposed no comets could
have lasted that close to the sun without getting baked away after a
few centuries or millennia.
Dirt coatings on main-belt comets could have protected them from
sunlight for billions of years. Every now and again boulders a yard or
larger tumbling around the asteroid belt might hit these comets,
uncovering their ice and triggering the plumes of gas and dust that got
them discovered in the first place.
"We expect to soon find many hundreds or thousands of main-belt comets," Jewitt said.
Interstellar comets?
As our solar system formed, calculations predict the gravitational
pull of the planets would have scattered 90 to 99 percent of all comets
that once orbited the sun away toward the stars, never to be seen
again. "If every star does that, you would expect some of their comets
to come toward us, but no such object has ever been seen," Jewitt said.
Still, as astronomical telescopes and techniques improve, Jewitt
remains optimistic that such interstellar comets will be detected
fairly soon. These comets would prove quite distinctive, zipping at
great speeds and following trajectories completely unlike the orbits
our comets follow.
"We could see interstellar comets for the first time in the next few
years," Jewitt predicted. "It would be great if we saw one, especially
so if we had the wherewithal to launch a mission to one, to get samples
and study the diversity of comets in an interstellar and galactic
context. But we have to find one first."
Comment: According to the gathered data and research, pretty soon Jewitt will have an opportunity to observe up close and personal
href="http://www.sott.net/articles/show/142651-Something-Wicked-This-Way-Comes">many of those interstellar comets.
No comments:
Post a Comment