What are the signs of spring? They are as familiar as a blooming
Daffodil, a songbird at dawn, a surprising shaft of warmth from the
afternoon sun. And, oh yes, don't forget the meteors. "Spring is
fireball season," says Bill Cooke of NASA's Meteoroid Environment
Center. "For reasons we don't fully understand, the rate of bright
meteors climbs during the weeks around the vernal equinox."
© NASA
A spring fireball recorded by a NASA all-sky camera located at the Marshall Space Flight Center on March 16, 2009.
A spring fireball recorded by a NASA all-sky camera located at the Marshall Space Flight Center on March 16, 2009.
Click here to watch movie.
In other seasons, a person willing to watch the sky from dusk to dawn
could expect to see around 10 random or "sporadic" fireballs. A fireball
is a meteor brighter than the planet Venus. Earth is bombarded by them
as our planet plows through the jetsam and flotsam of space--i.e.,
fragments of broken asteroids and decaying comets that litter the inner
solar system. In spring, fireballs are more abundant. Their nightly rate
mysteriously climbs 10% to 30%. "We've known about this phenomenon for
more than 30 years," says Cooke. "It's not only fireballs that are
affected. Meteorite falls--space rocks that actually hit the ground--are
more common in spring as well1."
Researchers who study Earth's meteoroid environment have never come up
with a satisfactory explanation for the extra fireballs. In fact, the
more they think about it, the stranger it gets.
Consider the following:
There is a point in the heavens called the "apex of Earth's way." It is,
simply, the direction our planet is traveling. As Earth circles the
sun, the apex circles the heavens, completing one trip through the
Zodiac every year.
The apex is significant because it is where sporadic meteors are
supposed to come from. If Earth were a car, the apex would be the front
windshield. When a car drives down a country road, insects accumulate on
the glass up front. Ditto for meteoroids swept up by Earth.
Every autumn, the apex climbs to its highest point in the night sky. At
that time, sporadic meteors of ordinary brightness are seen in
abundance, sometimes dozens per night.
Read that again: Every autumn.
"Autumn is the season for sporadic meteors," says Cooke. "So why are the
sporadic fireballs peaking in spring? That is the mystery."
Meteoroid expert Peter Brown of the University of Western Ontario notes
that "some researchers think there might be an intrinsic variation in
the meteoroid population along Earth's orbit, with a peak in big
fireball-producing debris around spring and early summer. We probably
won't know the answer until we learn more about their orbits."
To solve this and other puzzles, Cooke is setting up a network of smart
meteor cameras around the country to photograph fireballs and
triangulate their orbits. As explained in the Science@NASA story What's Hitting Earth?,
he's looking for places to put his cameras; educators are encouraged to
get involved. Networked observations of spring fireballs could
ultimately reveal their origin.
"It might take a few years to collect enough data," he cautions.
Until then, it's a beautiful mystery. Go out and enjoy the night sky. It is spring, after all.
Suspected meteorite impact? Arizona, US: Plane makes emergency landing; hole reported
Passengers say blast heard on Southwest flight before safe emergency landing
© via NBC news
This picture was taken by a passenger aboard the Southwest flight as it prepared to make an emergency landing.
This picture was taken by a passenger aboard the Southwest flight as it prepared to make an emergency landing.
Yuma,
Ariz. - A Southwest Airlines passenger jet flying from Phoenix to
Sacramento, Calif., made an emergency landing in Yuma, Ariz., Friday
after a hole opened up in the roof, officials said.
Flight 812, carrying 118 passengers, landed safely at Yuma Marine Corps
Air Station/International Airport at 4:07 p.m. after experiencing "rapid
decompression," the FAA said.
"Upon safely landing in Yuma, the flight crew discovered a hole in the
top of the aircraft," Southwest said in a statement. "There are no
reported customer injuries. One of the flight attendants, however,
received a minor injury upon descent."
The cause of the decompression was not known, FAA spokesman Ian Gregor
said. An FAA inspector from Phoenix was en route to Yuma.
Terrorism was not suspected because an FBI spokesman in Sacramento, Steve Dupre, said "it appears to be a mechanical issue."
Some passengers aboard the plane recounted moments of terror
after landing in Yuma. They said they heard what sounded like an
explosion that opened a hole in the cabin.
"They had just taken drink orders when I heard a huge sound and oxygen masks came down and we started making a rapid descent," a passenger named Cindy told Sacramento TV station CBS13.
"They said we'd be making an emergency landing. There was a hole in the fuselage about three feet long. You could see the insulation and the wiring. You could see a tear the length of one of the ceiling panels."
"You can see daylight through it," a passenger identified as Brenda Reese told Sacramento TV station KCRA by cellphone.
A Sacramento resident told CBS13 she received a text message from her
husband, who was aboard the flight: "Plane going down. Love you."
She said she heard from her husband a few minutes later after the plane
landed safely. The woman's husband said there was an explosion or a hole
in the plane, the TV station said.
Shawna Malvini Redden, another passenger aboard the flight, tweeted
after landing: "One flight attendant was injured and a couple passengers
passed out but nothing major."
Passengers became aware there was a problem when they heard a noise and
felt the rush of wind and oxygen masks started dropping in the cabin,
according to Reese.
She said a few people passed out "because their oxygen wasn't working. It was scary."
Reese said flight attendants went around the cabin aiding passengers.
Emergency medical technicians were on board the plane treating
passengers after it landed in Yuma.
Gina Swankie, a spokeswoman for Sacramento International Airport, said
Southwest was sending another plane to Yuma to take the passengers to
Sacramento.
"I want to get home and hold my three children," Reese said.
Southwest said it will work with the Federal Aviation Administration and
the National Transportation Safety Board to investigate the cause of
the mishap.
This story contains information from The Associated Press and NBC News.
Comment: In a separate report on this incident:
Bullet or Micrometeoroid? FBI probes possible bullet hole in US Air plane
The FBI is investigating what might be a bullet hole, discovered in
the side of a US Airways Group Inc (LCC.N) plane this week, the airline
said on Wednesday.
The small hole in the Boeing (BA.N) 737-400 was found by a pilot on
Monday at the Charlotte/Douglas International Airport in North Carolina.
"The pilot was doing his standard, pre-flight walk-around and noticed a
small hole in the rear, left fuselage," said US Airways spokeswoman
Michelle Mohr.
An FBI spokeswoman in Charlotte was not immediately available to comment on the investigation.
The aircraft had arrived in Charlotte from Philadelphia carrying 84
passengers and was scheduled to fly to Hartford, Connecticut, when the
hole was found.
The plane, designed to carry 144 passengers and five crew members, was
taken out of service on Monday and was scheduled to be back in service
on Wednesday, Mohr said.
Sugar-grain sized meteorites rocked the climates of early Earth and Mars
Bombardments of 'micro-meteorites' on Earth and Mars four billion
years ago may have caused the planets' climates to cool dramatically,
hampering their ability to support life, according to research published
today in the journal Geochimica et Cosmochimica Acta.
Scientists from Imperial College London studied the effects of the Late
Heavy Bombardment (LHB), a period of time in the early Solar System when
meteorite showers lasting around 100 million years barraged Earth and
Mars. This bombardment discharged sulphur dioxide into the upper
atmospheres of both planets and the researchers' analysis suggests that
this may have had a catastrophic impact on their environments.
Micro-meteorites come from the rocky asteroid belt between Mars and
Jupiter. These space rocks, which are the size of sugar grains, get
dragged by gravity towards Earth and Mars. As they enter the planets'
upper atmospheres, they heat up to temperatures of approximately 1000
degrees Celsius, releasing gases including sulphur dioxide. Sulphur
dioxide in the atmosphere forms aerosols, consisting of solid and liquid
particles, which deflect sunlight away from the surface, making planets
cooler.
The authors of the new study have calculated that showers of
micro-meteorites delivered approximately 20 million tonnes of sulphur
dioxide each year into the upper atmosphere of Earth during the LHB. The
team deduced that on Mars, these micro-meteorites delivered up to half a
million tonnes of sulphur dioxide each year for the same period of
time.
Professor Mark Sephton, an author of the study from the Department of
Earth Science and Engineering at Imperial College London, says:
"Far less of the Sun's energy was reaching Earth 4 billion years ago,
which would have made it hard for early life to emerge. Recently denied
of its protective magnetic field and constantly subjected to large
meteorite impacts, Mars was also starting to lose its greenhouse gases
at this time, causing global cooling. The influx of sulphur dioxide into
the Mars's atmosphere would have dealt a further blow to a planet
already on the ropes, making conditions for life even more of a
challenge."
The team say that such a large influx of sulphur dioxide into early
Earth's atmosphere had the same cooling effect on the climate as if
there was an eruption of the size of the 1991 Mount Pinatubo eruption
every year for 100 million years. The 1991 Mount Pinatubo eruption
released 17 million tonnes of gases, including sulphur dioxide, into the
atmosphere, preventing 10 percent of sunlight from reaching Earth and
cooling the planet by half a degree Celsius.
On Mars during the LHB, the scientists predict that the cooling effects
of sulphur dioxide on the red planet's atmosphere would have been the
equivalent of an eruption 1/34th the size of Mount Pinatubo occurring
every year for 100 million years.
The scientists say that the environmental consequences of sulphur
dioxide in Earth's atmosphere could have been disastrous. At this time,
the Sun's energy was 30 percent weaker than it is today, meaning less
energy was reaching the surface. The team believe that a weaker Sun,
combined with increasing levels of sulphur dioxide from
micro-meteorites, could have plunged Earth into an Arctic winter,
lasting millions of years and making conditions for primitive microbial
life extremely difficult.
On Mars, being further away from the Sun, the scientists suggest the
environmental consequences would have been even more dramatic. High
levels of sulphur dioxide would cause temperatures to plunge and water
on the surface, in the form of lakes and rivers, to disappear, turning a
warm wet world into a cold arid one.
Dr Richard Court, who is lead author of the study from the Department of
Earth Science and Engineering at Imperial College London, adds:
"These sugar-grain sized meteorites are left over material from the
construction of our early Solar System, helping to build rocky planets
such as Earth and Mars. Our study is helping us to see how these tiny
space rocks could also bring environmental devastation on a global scale
to early Earth and Mars."
The researchers came to their conclusions by simulating what happens to
micro-meteorites as they entered the atmosphere, using a technique
called flash pyrolysis to heat rock fragments that were identical to
micro-meteorites to 1000 degrees Celsius. They then used infrared
spectroscopy to measure the amount of sulphur dioxide released from
these rocks. The team then used their results and calculations of
meteorite in-fall rates during the LHB to determine how much sulphur
dioxide was delivered to Earth and Mars from micro-meteorites.
This study is a continuation of earlier work by the team who have
discovered that meteorites are not the source of the present-day methane
in the atmosphere of Mars, raising hopes that the methane is being
generated by life on the red planet. Their work has also shown that
meteorites delivered other important gases to Earth during its early
history that would have made it more habitable. In the future, the team
will assess the contributions gases from meteorites on planets outside
of the Solar System.
More information: "The contribution of sulphur dioxide from ablating
micro-meteorites to the atmospheres of Earth and Mars", 1 April 2011, Geochimica et Cosmochimica Acta
Micrometeoroid? Small cracks found in three Southwest Airlines jets
Mon, 04 Apr 2011 09:07 CDT
BBC News
© BBC News
Tests on Southwest's 79 other 737-300s are expected to be completed by Tuesday evening
Tests on Southwest's 79 other 737-300s are expected to be completed by Tuesday evening
Small, sub-surface cracks have been found in three more
Southwest Airlines planes like those thought to have caused another to
develop a hole in its cabin roof mid-flight, officials say.
The National Transportation Safety Board said it had been informed there
were additional crack indications in the lap joints on the Boeing
737-300s.
Nineteen other 737-300s showed no problems and will return to service.
The plane with the ruptured fuselage landed safely in Arizona on Friday.
Some of the 118 people on board the flight, which had just taken off from Phoenix, reported hearing a loud bang as a 1.5m-long gash appeared.
The hole caused a sudden drop in cabin pressure, forcing pilots to make a
controlled descent from 10,485m (34,400ft) to a military base. No-one
was seriously injured, though a flight attendant was slightly hurt.
'New and unknown issue'
On Sunday, a section of the 737-300's ruptured fuselage was removed and
sent to NTSB headquarters in Washington for in-depth analysis.
NTSB investigators also conducted inspections of other portions of the
lap joint along the fuselage and found evidence of additional cracks.
© BBC News
Passengers on board the Southwest Airlines flight described what happened
Later, the federal agency said in a statement that it had been informed
by Southwest that "crack indications in the lap joints have been
identified on three airplanes they have inspected".
Southwest cancelled 600 flights over the weekend to allow engineers to
carry out a special test developed by Boeing on 79 of its aircraft.
Tests on the 57 remaining jets are expected to be completed by Tuesday
evening. Further flight cancellations are likely until all are back in
the air.
The NTSB said Boeing would be drafting a "service bulletin" to describe
the inspection techniques that they would recommend carrying out on
similar planes with comparable flight cycles (take-offs and landings) as
the one involved in the accident over Arizona, which was 15 years old.
There are 931 such models in service worldwide, 288 based in the US.
"What we saw with Flight 812 was a new and unknown issue," said Mike Van de Ven, Southwest's executive vice-president and chief operating officer.
"Prior to the event regarding Flight 812, we were in compliance with the
FAA-mandated and Boeing-recommended structural inspection requirements
for that aircraft," he added.
"We regret any customer inconveniences as a result of the inspections
currently under way. Delays and cancellations are never the preference,
however we are taking every precaution we can to ensure that our
operation is safe."
Southwest changed its maintenance programme after metal fatigue caused a
similar accident on another of its jets in 2009. Before then, the
airline paid millions of dollars to settle charges that it was skipping
inspections.
In 1988, cracks caused a hole to open in an Aloha Airlines plane over Hawaii. In that accident, a flight attendant died.
A history doomed to be repeated? Micro-meteorites rocked Earth's early climate
Sat, 02 Apr 2011 06:25 CDT
Hindustan Times
© iStockphoto / duuuna
A
new research has claimed that bombardments of 'micro-meteorites' on
Earth and Mars four billion years ago may have caused the planets'
climates to cool dramatically, hampering their ability to support life.
Scientists from Imperial College London studied the effects of the Late
Heavy Bombardment (LHB), a period of time in the early Solar System
when meteorite showers lasting around 100 million years barraged Earth
and Mars.
This bombardment discharged sulphur dioxide into the upper atmospheres
of both planets and the researchers'' analysis suggests that this may
have had a catastrophic impact on their environments.
Micro-meteorites come from the rocky asteroid belt between Mars and
Jupiter. These space rocks, which are the size of sugar grains, get
dragged by gravity towards Earth and Mars.
As they enter the planets' upper atmospheres, they heat up to
temperatures of approximately 1000 degrees Celsius, releasing gases
including sulphur dioxide. Sulphur dioxide in the atmosphere forms
aerosols, consisting of solid and liquid particles, which deflect
sunlight away from the surface, making planets cooler.
The authors of the new study have calculated that showers of
micro-meteorites delivered approximately 20 million tonnes of sulphur
dioxide each year into the upper atmosphere of Earth during the LHB.
The team deduced that on Mars, these micro-meteorites delivered up to
half a million tonnes of sulphur dioxide each year for the same period
of time.
The study has been published in the journal Geochimica et Cosmochimica Acta.
4.5-Billion-Year-Old Antarctic Meteorite Yields New Mineral
A meteorite discovered in Antarctica in 1969 has just divulged a modern secret: a new mineral, now called Wassonite.
The new mineral found in the 4.5-billion-year-old meteorite was tiny -
less than one-hundredth as wide as a human hair. Still, that was enough
to excite the researchers who announced the discovery Tuesday (April
5). [Image of new mineral]
"Wassonite is a mineral formed from only two elements, sulfur and
titanium, yet it possesses a unique crystal structure that has not been
previously observed in nature," NASA space scientist Keiko
Nakamura-Messenger said in a statement.
The mineral's name, approved by the International Mineralogical
Association, honors John T. Wasson, a UCLA professor known for his
achievements across a broad swath of meteorite and impact research.
Grains of Wassonite were analyzed from the meteorite that has
been officially designated Yamato 691 enstatite chondrite. Chondrites
are primitive meteorites
that scientists think were remnants shed from the original building
blocks of planets. Most meteorites found on Earth fit into this group.
Yamato 691 likely originated from an asteroid
orbiting between Mars and Jupiter. It was discovered along with eight
other meteorites by members of the Japanese Antarctic Research
Expedition on the blue ice field of the Yamato Mountains. They
constituted the first significant recovery of Antarctic meteorites.
Follow-up searches by scientists from Japan and the United States have
recovered more than 40,000 specimens, including rare Martian and lunar meteorites.
The research team used NASA's transmission electron microscope to
isolate the Wassonite grains and figure out their chemical makeup and
atomic structure.
When meteors hit the ground they are called meteorites. Most are
fragments of asteroids (space rocks that travel through the solar
system), and others are mere cosmic dust shed by comets. Rare meteorites
are impact debris from the surfaces of the moon and Mars.
"Meteorites, and the minerals within them, are windows to the formation
of our solar system," said co-discoverer Lindsay Keller, space scientist
at NASA's Johnson Space Center in Houston. "Through these kinds of
studies we can learn about the conditions that existed and the processes
that were occurring then."
"Newly Discovered" Double Asteroid Flyby Today
Wed, 06 Apr 2011 10:44 CDT
Space Weather
© Unknown
US: "Ripping Fireball" over New Mexico
Space Weather
"There
was a rippingly fine fireball over north central New Mexico on April
5th at 01:50 am MDT," reports amateur radio astronomer Thomas Ashcraft.
"Signals from distant radio stations bounced off the meteor's trail as
it shredded the ionosphere. Here is a movie I made with the radio echo in stereo at two frequencies. The full radio reflection lasted more than two minutes."
US: Tennessee Fireball Caught on Video
SpaceWeather
Space rocks have landed in Tennessee. That's the conclusion of
researchers who recorded a brilliant fireball streaking over the Smoky
Mountain state on Wednesday evening. Bill Cooke of NASA's Meteoroid
Environment Office reports: "On April 6th at 8:21:57 CDT, NASA all-sky
meteor cameras detected a very bright fireball moving north across the
state of Tennessee. First detected 52 miles above the Arnold Air Force
base near Tullahoma, the meteor was brighter than crescent Moon and was
approximately 2 feet in diameter, with a weight of 200 lbs. It was last
recorded 30 miles above the town of Woodbury, Tennessee, moving at a
speed of approximately 9 miles per second (32,400 mph)."
Cooke continues: "The NASA Meteoroid Environment Office has reasonable
confidence that some fraction of this meteor survived to the ground as
one or more meteorites. Calculations are underway to determine the
general impact location, which may lie close to the Kentucky border.
Eyewitnesses to the fireball are encouraged to make a report to the American Meteor Society or to the Meteoroid Environment Office."
The smart cameras of Cooke's fireball network are able to
calculate the orbits of incoming fireballs and backtrack their
trajectories into the solar system. "The orbit of this interloper
indicates that it came from the Asteroid Belt, with an aphelion well
beyond the orbit of Mars."
Match made in heaven: Earth finds new companion as giant asteroid joins its path around the sun
The Daily Mail
But this asteroid orbits the sun in a highly unusual horseshoe pattern.
Earth has found a new companion that has joined its orbit around the sun, scientists have revealed.
It may not have the most romantic of names, but Asteroid 2010 SO16 could
pursue Earth for anywhere between the next 120,000 to a million years.
And at a few hundred metres across, it is the largest space rock ever discovered so close to earth.
But there is something unusual about SO16, say Apostolos
Christou and David Asher who discovered the giant floating rock last
September at the Armagh Observatory in Northern Ireland.
Rather than follow its new friend all the way round, SO16 orbits the sun
in a horseshoe shape, playing a constant game of catch up with Earth,
they say.
The closer to the sun an object is, the faster it will orbit.
So when SO16 entered the sun's orbit, it was further away than Earth and therefore slower.
When Earth finally caught up with the asteroid, instead of overtaking
it, its gravitational pull drew it closer to the sun sending it back
round at a faster pace.
Now
quicker than Earth, SO16 speeds round its shorter orbit until it
catches Earth again and is this time pulled away from the sun, slowing
it down.
More simply, from the point of view of the Earth, the asteroid has a
horseshoe-shaped orbit, constantly moving towards and away from the
Earth without ever passing it.
But from the asteroid's point of view, it orbits the Sun continuously in
the same direction, more quickly in smaller orbits and more slowly in
bigger ones.
Christou and Asher say this process is repeated over and over again until the asteroid dies.
At the moment SO16 is travelling at one of its closest approach points
and will be visible in the evening sky for several decades to come.
A Different Kind of Catastrophe - Something Wicked This Way Comes
In June 1908, an explosion rocked a remote, swampy area in central
Siberia, in Russia; it came to be known as the "Tunguska event." A later
expedition to the site found that 20 miles of trees had been knocked
down and set alight by the blast. And today, it is understood that
Tunguska's devastation was caused by a 100-foot asteroid that had
entered Earth's atmosphere, causing an airburst.
Some 13,000 years earlier, just after the end of the last ice age, the
Earth's climate had begun to warm up to temperatures like we enjoy
today, when an occurrence thought by some researchers to be an
extraterrestrial impact set off an "impact winter". And caused a return
to ice age conditions that lasted another thousand years, or so. The
"Younger Dryas event," as it is known, coincided with the end of the
prehistoric Clovis culture. And the mass extinction of almost all of the
giant animals that lived on North America at the time.
Before the Younger Dryas event, much of north America had an ecology
similar to what we see today in the lush African savanna. And after the
YD event more then 35 genera had vanished. The giant sloth, short faced
bear, dire wolves, saber toothed cats, a species of camel, horses, and
two species of elephant were wiped out by the YD event. And that's just
the short list. All of that astonishing biodiversity was blown away.
Perhaps the single most important paper on the subject of the Younger
Dryas, is the 2007 paper by R.B. Firestone et al, and titled: Evidence
for an extraterrestrial impact 12,900 years ago that contributed to the
megafaunal extinctions and the Younger Dryas cooling.
In that paper, a team of twenty six scientists, studying sedimentary
deposits presented a whole suite of compelling evidence for a massive
impact event of a comet that appears to have broken up, and scattered,
fragments all across North America. The multiple, air bursts are thought
to have triggered wide spread bio mass burning on a continental scale.
As well as causing a return to ice age conditions, and the extinction of
many species. Including the mega fauna like mastodons, wooly mammoths,
and giant sloths.
That paper caused a pretty good stir in the academic
community. And it has become the 'Flagship', so to speak, of the Younger
Dryas impact hypothesis. But while they had good evidence from the
ground that a very large impact had occurred in the recent past, it was
clear that the event was vastly different from anything that had been
studied before. And without an astronomical model that could confidently
describe the nature of the impactor/s, they were were at an impasse.
"Where's the crater?" became a rallying cry of opponents to the
hypothesis.
But in fact, impact research is an infant science. Who is to say what a
full suit of impact markers should be? And what of airburst blast
effects? Who says the event had to produce a crater?
Tunguska of 1908 was the largest impact event in recorded history. And
yet, the blast affected materials at ground zero do not qualify it as an
impact structure. Indeed, if there hadn't been any eye witnesses, our
impact scientists would be in complete denial of an ET origin for all
the violence there that day. There is no reason to think Tunguska was an
isolated event. Or even a big one, on the grand scale of such things.
At Sandia Labs, Mark Boslough used their 'Red Storm' supercomputer to
simulate the airburst and impact of a 120-meter diameter stony asteroid.
The colors in the simulation we see below are graded by temperature.
White = 5800K; Red = 2000K. Dr Boslough tells us that, in it, we see
the ablated meteoritic vapor mixes with the atmosphere to form an opaque
fireball with a temperature of thousands of degrees. As it hits the
ground, the hot vapor cloud expands to a diameter of 10 km within
seconds, remaining in contact with the surface, with velocities of
several 100m/s. And at temperatures exceeding the melting temperature of
quartz for more than 20 seconds. Moreover, the air speed behind the
blast wave exceeds several hundred meters per second during this time.
For comparison, an ordinary oxy-acetylene cutting torch in a steel shop
uses a thin stream of hot gases at only about 900 degrees C. and 40PSI
to cut steel. The speed of that stream of hot gasses is only a little
bit more than a stiff breeze. But that's all it takes to turn solid iron
into a melted, aerosol, spray. And to blow it away in runnels of melt
into heaps of slag.
Dr Boslough tells us that: "Simulations suggest strong coupling of
thermal radiation to the ground, and efficient ablation of the resulting
melt by the high-velocity shear flow."
We have its existence predicted in peer reviewed literature. But so far I
haven't heard anyone attempt to describe the form that such
geo-ablative melt might take as it is emplaced. While in motion, any
ablated materials from a large, geo-ablative, airburst like that would
be in atmospheric suspension, in a density current similar to a
pyroclastic flow. And when everything comes to rest, the resulting rock
form might be visually indistinguishable from ordinary volcanic tuff, or
ignimbrite. If so, we face a conundrum in the Earth sciences. Because
it has always been assumed without question that only terrestrial
volcanism can melt the rocks of the Earth, or produce 'Tuff'.
If very large airbursts can produce formations of geo-ablative melt,
instead of craters, then almost every last pebble of airburst melt on
this fair world of ours has been mis-defined as volcanogenic.
Astronomers Victor Clube, and William Napier, had been talking about the giant comet they described as the progenitor of the Taurid Complex since 1982, in their book The Cosmic Serpent.
But no one had connected the dots, and put the Younger Dryas comet, and
the Taurid Progenitor together. Except in private, speculative, emails,
and letters. And to the best of my knowledge there was nothing in
refereed literature.
Then, In early 2010 Professor Napier published a paper in the Journal Monthly Notices of the Royal Astronomical Society titled, Paleolithic extinctions and the Taurid Complex in it we read:
It was indeed an astronomical catastrophe. And the nature of the event
bears no resemblance whatsoever to anything in any NEO hazard
assessments, or anything in current impact theory.
With Professor Napier's work specifically proposing in refereed
literature that the Taurid Progenitor was the Younger Dryas comet, he
changed the game completely. Because he didn't just give us a convincing
astronomical model of the event. We also have a pretty good picture of
the physical properties of the thing that did the disastrous deed. And
if you can describe a beast, you can predict its footprints.
It is important to note here that the astronomical model of the Taurids
implies that most catastrophic impact events are probably the result of a
very large cluster of smaller fragments, and cometary debris. And not a
single, large bolide.
Mark Boslough's simulations predict the temps, pressures, flow
directions, and rotation speeds, of a single impact down-blast vortex.
And since we are working from postulate that the events of the YDB were
caused by the impact storms, of the debris streams, of the fragmented
Taurid progenitor. The YD impact hypothesis as it stands, describes tens
of thousands of such airbursts in a little over an hour. And
accompanied by clouds of particles down to the size dust grains falling
into the atmosphere at something like 30 km/per second, as the Earth
crossed through the orbital path of the giant fragmented comet's debris
stream.
Firestone, and friends proposed destructive forces equivalent to as much as 109
megatons of TNT. And at temps hotter than the surface of the sun. (a
half pound of TNT will blow a hole in the ground you could lose a small
car in)
Professor Napier states "The interception of ~1015 gm of
material during the course of disintegration is shown here to have been a
reasonably probable event, capable of yielding destruction on a
continental scale." Using a gram scale to weigh a giant comet is like
giving the distance to moon in inches. The total mass of the fragments
that hit the Earth that day works out to well over 1.1 billion tons. 109 mega tons TNT of destruction doesn't seem like such a stretch, when you work out how big the parent comet was.
The Deep Impact
mission to comet TEMPEL 1 showed the head of that comet to have the
consistency of a dirty snow bank. It also showed that the object is a
geologically active body. Comet HOLMES is unstable, and prone to violent outbursts. Comet LINEAR,
and Comet Scwassmann-Wachmann 3, shown here make it abundantly clear
that total, explosive, fragmentation of a comet can occur spontaneously
at any time. And it can happen before it even gets close to a planet. It
doesn't need the atmosphere to do that.
If you can describe a beast, you can predict its footprints. Since the
YD impact hypothesis has become a fully fledged theory that gives a
specific description of the exact nature of the impactors, then it
follows that we should also be able to predict the nature, and severity,
of the blast effected materials. Only the first fragments to fall would
have fallen into cold atmosphere. The rest would have fallen into
already superheated atmosphere, and just cranked up the heat, and
pressure. So we're not necessarily looking for craters where solid
bolides hit the ground. We are looking for the signatures, whatever they
might be, of a 'Perfect Storm' of ablative airbursts, with winds
gusting to supersonic, and downdrafts hotter than the surface of the
sun. In the impact zones, the surface of the Earth didn't get smashed
and broken by the event. It was flash melted, and blown away.
Extraordinary hypotheses require extraordinary proofs. If the Younger
Dryas Impacts were, in fact, the multiple airburst impact storms of the
Taurid Progenitor, then there should be hundreds of thousands of cubic
miles of flash melted rock, and blast effected materials, on this
continent, as pristine as the day they first cooled. And with no giant
volcanic system to account for them. And in fact, such continental
scale, orphaned materials do indeed exist. And they can be found in two
large geologically recent, multiple airburst, impact zones. One is The Northeast Impact Zone,
extending from the Great Lakes to the Arctic circle. And the other
major impact zone can be found in central Mexico, and extends up into
west Texas, and New Mexico.
The Chihuahuan Ignimbrites of central Mexico
have always been a mystery as to their source. Generations of
geologists have assumed they must be volcanogenic. And one typically
hears the excuse that it could take decades to find the vents, and magma
chambers it all came from. But of more than 350,000 cubic miles of
pristine pyroclastic materials in the Chihuahuan Desert, and the Sierra
Madre Occidental mountains, less than 15% can be attributed to a
volcanic system. And when we use modern high resolution satellite
imagery to view the typical Airburst Impact structure
at 29.702168, -105.686617 we can see why. That structure, and the
geo-ablative curtain of airburst melt surrounding it, is typical of more
than 50,000 square miles. And terrestrial volcanism had nothing to do
with it.
The high resolution satellite imagery that's become available in the
past decade has revealed a new perspective that hasn't been available
to geologists of the past. Answering the question of where those
pyroclastic materials came from is easy when you can read the patterns
of movement, and flow, that were frozen in time from the moment of their
emplacement. And as easily as following splashes of spilled paint back
to a can.
The most startling revelation will come from studying those perfectly
legible patterns of flow. And when you realize that gravity pulling them
down a slope, and away from a vent, was not the motive force while they
were in motion. And that you are looking at wind-driven patterns of
movement, and flow, during the emplacement event, like the froth, and
foam on a storm tossed beach. And when you begin to see that those
pyroclastic flows describe a completely different kind of non-volcanic
catastrophe from anything ever imagined before.
What kind of naturally occurring, non-volcanic, event can flash melt,
and ablate, the surface of the Earth, and turn more than 50,000 miles
into a single random colliding, inter-flowing, wind-driven, sheet of
pyroclastic flows, and ablated landforms? Or suddenly blast away a large
section of an ice sheet as big as the continental United States?
Imagine along with me for a moment. What say we take a great big comet,
say 50 to 100 km wide, out of the Oort Cloud, or the Kuiper belt, and
inject it into the inner solar system. And we park it an elliptical,
Earth crossing orbit, and break it up into not so little pieces. Let's
give it enough time for tidal forces to break it up completely, and
stretch it out into a very long debris stream of particles, and
fragments. Our average fragment size was about the size of the Tunguska
object. But they ranged from more than a half mile wide, all the way
down to clouds of dust.
As the Earth's orbit brings it across orbital path of the giant,
fragmented comet's debris streams, the fragments begin to fall into the
atmosphere from the south at a low angle. And more than 30 km/sec. The
first fragments to hit will produce atmospheric temps well over 100,000
degrees C. And they are just cheerleaders, twirling batons in front of a
parade. The rest fall into already superheated impact plasma, and just
crank up the heat, and pressure. In this way, almost 100% of the kinetic
energy of the fragments gets translated to heat, and pressure in the
atmosphere. And that heat, and pressure, hits the ground as an almost
continuous, supersonic, stream of airbursts, hotter than the surface
sun.
With just a few short minutes of that, I'll bet we could sterilize the
whole lush, African Savanna, and make it look just like central Mexico,
and the American Southwest. And in fact, according to the fossil
record, every mega-faunal ecological niche we see in the African
Savanna, and more, is represented in the fossils below the Younger Dryas
Boundary layer. But not above it. All that astonishing biodiversity was
burned, and blown away in seconds.
Sound Crazy? Not so fast. The 2007 Firestone paper cited Toon et al when they proposed temps as high as 107degrees
C. There's that exponential thing again. That's 10 million degrees
Celsius. But Professor Napier pointed out for me that even if a bolide
hits the atmosphere at 30 kilometers per second, and all of its kinetic
energy is translated to heat in the atmosphere, it is difficult to get
more than 100,000o C. But that's ok. Because either way, even
with the more conservative figure, we are still describing temperatures
that are more than enough to vaporize any known substance on the
surface of the Earth. And to blow it away like wax under a high pressure
blowtorch.
A compelling, almost conclusive, case can be made for the argument that
the Younger Dryas cooling, the mega faunal extinctions of the early
Holocene, and the demise of the Clovis people were all caused by the
same event. It was the multiple, thermal airburst, impact showers of
the fragments of the Taurid Progenitor soon after its complete breakup.
And the thermal explosive catastrophe its debris stream brought, was
more violent than anything ever imagined.
In the simulation we see above, Dr Boslough simulated a single bolide.
The blast effected materials of the event describe a giant stream of
fragments such as that, accompanied by clouds of particles down to the
size of dust grains.
No one has ever found a crater that can be dated to the event. But that
much heat, and pressure, only goes away peacefully in children's
bedtime stories. And no craters, does not mean there are no planetary
scars.
Because it was already broken up before the Earth encountered its debris
stream. The atmosphere translated nearly all of the kinetic energy into
heat. But it didn't dissipate it. It transferred the heat directly to
the ground in an almost continuous rain of devastating supersonic,
geo-ablative, down-blasts.
The eastern end of the Laurentide Ice sheet got hit in an area from
Northern Minnesota, and the Great Lakes to the Arctic Circle. When the
first down-blasts of thermal impact plasma hit the Laurentide Ice sheet
they caused titanic, hot and powerful, hydrothermal explosions (steam)
that lofted huge icebergs hundreds of miles in all directions.
A few short minutes later, those flying chunks of ice were the
impactites that formed the thousands of oval depressions all over the
eastern side of the continent called the "Carolina Bays". And the signs
of massive flooding that have been attributed by generations of
geologists to the bursting of ice damns holding back Glacial lake Agassiz are, in fact, the flood effects of the flash melting of major portions of the eastern end of the Laurentide ice sheet.
In a matter of minutes, much of the eastern end of the LIS was
obliterated. Much of which probably went into the atmosphere as steam.
The immense hydrothermal explosions also lofted the iceberg sized chunks
of ice that produced the Carolina Bays when they fell back to Earth.
The other much larger cluster of fragments hit in central Mexico, and
the American southwest. The Earth was probably in the path of the
devastating streams of high velocity, air bursting comet fragments for
about an hour. And out of tens of thousands of large, air-bursting,
fragments there is not one single impact structure that bears any
resemblance to what standard impact theory might expect. Or a "full
suite of impact hallmarks" all of the planetary scarring of the event
has been mis-defined as volcanogenic. And most of the ages of those
blast effected materials have been over estimated by orders of
magnitude.
The most devastating geo-ablative effects were in central Mexico, and
the American Southwest. In seconds all of central Mexico was pulverized
into a surreal, and blasted, landscape of heavily ablated, and melted
terrains, like a Salvador Dali painting. It generated a post impact mega
tsunami of thermal impact plasma taller than the atmosphere, hundreds
of miles wide, and hundreds of miles from front to back, that rushed
downrange to the northwest at supersonic speeds. And it sterilized the
western half of the continent on a swath from Mexico to the Arctic,
along a storm front extending from California to the great plains.
The Mexican cluster of fragments was approximately 500 miles wide. As
the first of the fragments hit they detonated high in the atmosphere.
But the explosions retained their momentum. And they hit the ground as
devastating supersonic down blasts hotter than the surface of the sun.
And as I said, only the very first fell into cold atmosphere. The rest
of the fragments just piled on in, and added to the heat, and pressure.
The overpressures from the blast waves were so powerful they blasted
whole mountain ranges aside like clumps of flour on a bakers table. And
still, they continued to pile in. And the heat, and overpressures,
continued to build.
The blast wind would've incinerated everything it passed over. In the
hottest part of the impact zone, vast quantities of stone were
vaporized, and whipped up into the storm, where the atmosphere worked
like a refining tower. And in a fiery rain the materials precipitated
out of the plasma storm down wind according to their condensation
temperature, and specific gravity. This was like nothing ever imagined
in our most frightening nightmares of disaster, or catastrophe. During
the impacts, and for a few minutes after, most of North America from
Mexico to the Arctic, and from California, to the plains of the Midwest,
was engulfed in what might best be described as a full blown
magneto-hydro-dynamic plasma storm. Like something we should only expect
to find on the surface of the sun. And there is not one square inch of
the surface terrains of western North America in its path that doesn't
bear the scars of that blast of heat.
In fact look closely in modern satellite images. You see that all of the
high ridges of the mountain ranges of California, Colorado, Utah,
Wyoming, and Montana that had glaciers at the time bear clear and
obvious signs of the heat. And a profound feature that is easy to spot
is melted glacial ridges, blown over to the north and northwest like
runnels of melted wax on the side of a candle. And we typically see high
glacial valleys below those melted ridges that have all of the material
that was once suspended in the Glacier lying exactly below where it was
in the glacier. Indicating that the ice evaporated so fast there was no
flow of water down slope to move any of the glacial till. So we see
that the glacial till dropped out so fast it's as if the ice just
vanished in a quick puff of steam.
Almost at the same time Mexico was getting hit, the eastern end of the
ice sheet was getting pounded just as hard. But the ice added another
factor to consider in understanding the blast effects. Under the thermal
airburst down-blasts, the ice reacted explosively, like reactive armor
on a battle tank. The impacts into the ice sheet triggered titanic
hydrothermal explosions that lofted huge berg sized chunks of ice for
hundreds of miles forming the 'Carolina Bays'.
The ice sheet impacts evaporated millions of acre feet of water directly
into the atmosphere. There was probably much more of the ice sheet that
went up as steam, only to rain down in the days, and weeks, that
followed than was melted to flow into the sea. As North America burned,
the storms around the world raged. It rained everywhere for weeks.
Sea levels rose as the blasted, and melted ice sheet flowed in mega
floods to the sea. And just as today, most of the larger populations
would have been in low lying areas. The seas rose too fast or anyone,
and anything, living in coastal areas anywhere in the world, to escape.
Every coastline all over the world was effected. And everywhere it would
have been much like a giant tsunami. But this time, the flood waters
rose and never receded.
Much of an ice sheet bigger than the Continental United States was
destroyed. The whole world was shaken to the core. And, like taking
weight from a floating barge, the sudden shift of the weight of so much
ice caused a massive uplift of the middle of the continent. Coupled with
the powerful detonations of so many exploding comet fragments, it
caused earthquakes, and volcanic eruptions all over the world. And
global seismic activity was the worst in many millions of years.
While the mega floods from the blasted ice sheet were still flowing into
the sea. Most of the biomass of western North America was burned away
and much of the resultant smoke, and soot was blown high above the
atmosphere where it blocked sunlight for years. There was an immediate
sharp drop in temperatures world wide. It was the worst kind of 'Perfect
Storm'. Made all the worse because at the same time the destruction of
the LIS caused a sudden rise in sea levels world wide. It it may have
caused a shutdown of the thermal haline cycle which brings tropical
warmth to the North Atlantic. Be that as it may, Northern Europe quickly
cooled to arctic temperatures. And the cold remained for centuries.
The Clovis people, and whole species, and ecosystems, were annihilated
in seconds. Most of the western half of the continent was incinerated,
and sterilized. The other half was devastated. The food chain of the
entire northern hemisphere was severely compromised. And except for
rare, and random, patches here, and there, that remained somehow
unscathed like the one surviving undamaged house in a neighborhood hit
by a tornado. The lush savannah the giant animals of North America
depended on for food was gone down to the last blade of grass. Those
giant animals that survived in the southeast corner of the continent
faced a drastically altered, and reduced food supply. And they simply
starved. The specialist predators that depended on those animals for
food perished as well. The species that survived extinction were the
most adaptable, the smaller ones that didn't eat much, and those that
were just plain lucky.
If there were any human survivors of that day, anywhere in the western
hemisphere, they were hiding in a deep cave somewhere well south of the
impact zone. And they were cringing in terror as their world was erased
and made new again. Any who peeked out of the cave without getting
themselves killed, may have told stories of fire breathing dragons
remaking the world with breath so hot it could melt mountains.
The progression of the event was a result of the Earth's movement along
its orbital path, as it crossed through the orbital path of the giant
comet's debris stream. Not a product of the Earth's rotation. So that,
in a daytime event, the fragments are outbound from perihelion. The
airburst storms would begin in the west, and progress to the east. As
the Earth Crosses the debris stream. In a night time event, the debris
stream would be inbound towards their perihelion, and the opposite would
be true.
Using modern satellite imagery, a very compelling case can be made that
the scenario described above is very close to the exact truth. The
remaining debris of the Taurid Complex is still out there. And there are
still fragments of significant size in Earth crossing orbits. It is
almost a certainty that the next major impact event will be an airburst.
And it is a certainty that we haven't seen the last catastrophic impact
of the Taurid Complex.
Something wicked this way comes.
US: Bright Fireball Leads To Meteorite Search In Tennessee
Space Daily
Did you see a bright flash in the sky over Tullahoma, Tenn., last night? Have we got a scavenger hunt for you...
At approximately 08:21:57 p.m. CDT on April 6, 2011, NASA all-sky meteor
cameras located at the University of Tennessee Space Institute, in
conjunction with the Hands-On Science Center in Tullahoma, Tennessee,
and at the Walker County Science Center in northwest Georgia detected a
very bright fireball moving north across the state of Tennessee.
First detected 52 miles above the Arnold Air Force base near Tullahoma,
the meteor was brighter than crescent moon and was approximately two
feet in diameter, with a weight of 200 lbs. It was last recorded 30
miles above the town of Woodbury, Tenn., moving at a speed of
approximately nine miles per second, or 32,400 mph.
The NASA Meteoroid Environment Office has reasonable confidence
that some fraction of this meteor survived to the ground as one or more
meteorites. Calculations are underway to determine the general impact
location, which may lie close to the Kentucky border.
Eyewitnesses to the fireball are encouraged to make a report to the
American Meteor Society at www.amsmeteors.com, or to the Meteoroid
Environment Office.
More information will be forthcoming at the completion of the impact
zone calculations, which may take some time. The orbit indicates that
this interloper was from the Asteroid Belt, with an aphelion well beyond
the orbit of Mars.
Earth to Get Very Close Look at a Huge Asteroid
Flyby in November sparks extensive campaign for all kinds of observations
Mark your calendars for an impressive and upcoming flyby of an asteroid
that's one of the larger potentially perilous space rocks in the heavens
- in terms of smacking the Earth in the future.
It's the case of asteroid 2005 YU55, a round mini-world that is about
1,300 feet in diameter. In early November, this asteroid will approach
Earth within a scant 0.85 lunar distances.
Due the object's size and whisking by so close to Earth, an extensive
campaign of radar, visual and infrared observations are being planned.
Asteroid 2005 YU55 was discovered by Spacewatch at the University of
Arizona, Tucson's Lunar and Planetary Laboratory on Dec. 28, 2005. En
route and headed our way, the cosmic wanderer is another reminder about
life here on our sitting duck of a planet.
Close and Big
"The close Earth approach of 2005 YU55 on November 8 is unusual since it
is close and big. On average, one wouldn't expect an object this big to
pass this close but every 30 years," said Don Yeomans, manager of
NASA's Near-Earth Object Program Office and the Jet Propulsion
Laboratory in Pasadena, Calif.
Yeomans said that with new radar capabilities at Goldstone in California
- part of NASA's Deep Space Network - there is a good chance of
obtaining radar imaging of 2005 YU55 down to the 5-meter resolution
level. Doing so, he said, would mean obtaining higher spatial resolution
of the object than that attained by recent spacecraft flyby missions.
"So we like to think of this opportunity as a close flyby mission with
Earth as the spacecraft," Yeomans told Space.com. "When combined with
ground-based optical and near-infrared observations, the radar data
should provide a fairly complete picture of one of the larger
potentially hazardous asteroids," he said.
Asteroid 2005 YU55 is a slow rotator. Because of its size and proximity
to Earth, the Minor Planet Center in Cambridge, Mass., has designated
the space rock as a "potentially hazardous asteroid."
Dishing It Out
"We're already preparing for the 2005 YU55 flyby," said Lance Benner, a
research scientist at JPL and a specialist on radar imaging of
near-Earth objects. He said part of the plan is to observe the asteroid
with radar using both the huge Arecibo dish in Puerto Rico and equipment
at Goldstone.
"The asteroid will approach from the south, so Goldstone has the first
chance to observe it due to its declination coverage," Benner told
Space.com.
To help coordinate the observing campaigns, "Radar Observations
Planning" websites have been set up for this unusual occasion, Benner
said.
"This flyby will be the closest by any near-Earth asteroid with an
absolute magnitude this bright since 1976 and until 2028," Benner added.
"Having said that, nobody saw 2010 XC15 during its close flyby within
0.5 lunar distance in 1976," he said, noting that this asteroid wasn't
discovered until late in 2010.
"Thus, the flyby by 2005 YU55 will be the closest actually observed by
something this large, so it represents a unique opportunity," Benner
said. "In a real sense, this will provide imaging resolution comparable
to or even better than a spacecraft mission flyby."
Radar Paint
Benner said that because the asteroid is zooming by Earth so very close,
radar echoes will be extremely strong. One facility at Goldstone will
be used to transmit and "radar paint" the object ... another Goldstone
dish is on tap to snag the reflected echo of radar data.
What Can Radar Do?
Information collected by this technique, for example, can be transformed
into 3-D shapes, with surface features and spin rates identified. The
asteroid's roughness and density also can be assessed. Furthermore,
radar can improve the whereabouts of the object. By greatly shrinking
uncertainties for newly discovered meandering NEOs, that in turn enables
motion prediction for decades to centuries.
As for seeing the asteroid with small telescopes, start getting your gear ready.
Initially, the object will be too close to the sun and too faint for
optical observers. But late in the day (Universal Time) on Nov. 8, the
solar elongation will grow sufficiently to see it. Early on Nov. 9, the
asteroid could reach about 11th magnitude for several hours before it
fades as its distance rapidly increases, Benner explained.
Leonard David has been reporting on the space industry for more than
five decades. He is past editor-in-chief of the National Space
Society's Ad Astra and Space World magazines and has written for Space.com since 1999.
Comment: The reader may be interested in Planet-X, Comets and Earth Changes by J.M. McCanney.
US: Loud Mysterious Sound Heard In Calaveras County, California
Calaveras County Sheriff's Detectives are investigating a loud
explosive sound that was reported in several communities yesterday.
According to the Sheriff's Office, at around 8:50 am, the Sheriff's
dispatch received multiple 9-11 calls from San Andreas, Mokelumne Hill,
Mountain Ranch, Railroad Flat and West Point. All of the callers said that heard a single loud explosion type noise, but there were no reports of fire or smoke being seen and no specific location given.
Several callers also stated that a plane had flown overhead just prior
to the loud explosion and they suspected it was a sonic boom. Sheriff's
Dispatch checked with the FAA and Calaveras County Airport who had no reported planes in distress in the area.
The Sheriff's Office will also follow-up with local military contacts in
an attempt to confirm the possible sonic boom that was heard by many
county residents.
Comment: Sott.net has picked up many reports of similar mysterious booms recently:
Ohio, US: Newark Police Puzzled By Mystery 'Boom'
'Mushroom-shaped light and loud boom' rocks remote Siberia
US: 'Boom' Heard Across Southeast Oklahoma
US: Big Boom Remains a Mystery
US: Mysterious Boom Rocks Region
California, US: Source of Loud Boom Continues to be Mysterious
US: Mystery Sonic Boom Rattles Georgia
US: Mystery Blast Likely a Sonic Boom, Official Says
The Dark Ages: Were They Darker Than We Imagined?
Published in the September 1999 issue of Universe.
As we approach the end of the Second Millennium, a review of ancient
history is not what you would normally expect to read in the pages of Universe.
Indeed, except for reflecting on the AD 837 apparition of Halley's
Comet (when it should have been as bright as Venus and would have moved
through 60 degrees of sky in one day as it passed just 0.03 AU from
Earth - three times closer than Hyakutake in 1996), you may well wonder
what we could learn from any astronomical events that occurred more than
a thousand years ago.
Any history text will say that the Dark Ages refers to the period after
the fall of the Roman Empire in the middle of the 1st Millennium (it was
not sponsored by the International Dark Sky Association). It was a time
when European civilisation stagnated - even that term is a generous
description of the living standards and social setting of the next few
centuries. In a broader sense, however, "Dark Ages" can be applied to a
few eras of social upheaval over the last several thousand years, which
fits in nicely with what you're about to read - stay with me, as the
possible astronomical implications will soon become apparent.
Physical Aspects Of The Dark Ages
Let's first look at the onset of "the" Dark Ages in the sixth century
AD. The Roman Empire was finished, nothing was happening in the
sciences, and worse was happening in nature. The Italian historian
Flavius Cassiodorus wrote about conditions that he experienced during
the year AD 536:
Other writers of the time described similar conditions:
Was this a local phenomenon? According to the book Volcanoes of the World,
Dr. Timothy Bratton has noted that there was a small eruption of the
volcano Mt. Vesuvius in AD 536. Could this be the cause? It may well
have contributed to the scene (although the eruption was much smaller
than the big one of AD 79), but it can not really account for the
similar conditions that were experienced around the world.
In China, "the stars were lost from view for three months". Records
indicate that the light from the Sun dimmed, the expected rains did not
eventuate, and snow was seen in the middle of summer. Famine was
widespread, and in the midst of the turmoil, the Emperor abandoned the
capital.
Bad luck tends to get bunched together, and thus came the
plague. The Justinian Plague, named after the Byzantine Emperor of the
time, is reported to have begun in central Asia, spread into Egypt, and
then made its way through Europe. By some accounts, it was as bad as the
Black Death which "plagued" Europe in the Middle Ages.
A Different Branch Of The Picture
Mike Baillie is Professor of Palaeoecology at Queens University,
Belfast, Northern Ireland. He is an authority on tree rings and their
use in dating ancient events (every year, a tree adds a "ring" to its
trunk as it grows - good years are represented by thick rings while bad
years are represented by thin rings). He conducted a complete (and
continuous) review of annual global tree growth patterns over the last
5,000 years and found that there were five major environmental shocks
that were witnessed worldwide. These shocks were reflected in the ring
widths being very thin. Wanting to know more, he turned to human
historical records, and found that the years in question (between 2354
and 2345 BC, 1628 and 1623 BC, 1159 and 1141 BC, 208 and 204 BC, and AD
536 and 545) all corresponded with "dark ages" in civilisation.
The minimal growth of trees around 2350 BC has been associated in the
past with the eruption of a volcano in Iceland. Yet, the period in
question is also associated with floods, the creation of new lakes, and
even the start of Chinese history. Furthermore, Marie-Agnes Courty, an
archaeologist from France, has claimed new data regarding a catastrophe
said to have occurred in the Middle East. Samples from three separate
regions all appear to contain a calcite material found only in
meteorites, and analysis of debris show what seems to be a combination
of "a burnt surface horizon and air blast."
Indeed, some 40 cities throughout North Africa, the Middle East, Europe,
and Asia are thought to have been devastated, or even disappeared,
about the same time in a series of catastrophes.
The twelfth century BC is associated with the "Greek Dark Ages", the end
of the Hittite civilisation in the Near East, the end of Bronze Age
Israel, and the end of the Bronze Age Shang dynasty in China. Ancient
Chinese history has the notion of "mandate from heaven", where the
rulers were essentially subject to the whims of the sky above. Strange
sights in the sky would not be seen as good news for Chinese Emperors.
Indeed, around this time, Chinese records speak of:
What could cause such global shocks? A likely answer, which has a good
fit to the evidence, was what the European and Chinese observers
described at the time as "dragons in the sky" - comets! We're not
talking about an intact large comet (if that had hit in the last several
millennia, we would not be here today), but rather fragments from a
disintegrating comet or asteroid (small pieces like that which hit
Tunguska in 1908). These would throw up dust that would envelope the
world and dim our view of the Sun and skies.
All this sounds like an interesting theory, but is there any evidence
"above us" that fits in with the scenario. How do we account for so many
impacts over the last several millennia when the consensus today in
astronomy is that impacts causing global consequences (mild as well as
major) are very rare?
Enter The Astronomers
Independently of Baillie's studies, British astronomers were putting
together an explanation of the Taurid meteors that we see. The Taurids
are related to comet Encke, as first shown by Fred Whipple, best known
for proposing the "dirty snowball" model of comets. Mark Bailey, Victor
Clube (brother of my rugby coach at school!), and Bill Napier put
forward the theory that Encke and the Taurid meteors originated from a
giant comet that fragmented some 40,000 years ago after entering the
inner Solar System. The idea of a comet splitting up into smaller pieces
is nothing new (witness Shoemaker-Levy 9 in 1994 and the return this
year of the fragmented periodic comet Machholz 2), and indeed Dr. Brian
Marsden of the Smithsonian Astrophysical Observatory is the originator
of the idea that the bulk of sungrazing comets we see come from a large
comet that perhaps originally split a few centuries before Christ, and
has split again - this family of comets is known as the Kreutz
sungrazers.
The astronomers noted that Chinese records of meteor observations over
the last two thousand years revealed significant surges in the number of
meteors observed every few centuries. These tended to be observed at
the same time every year - we now know of them as the Taurids, which has
a nighttime display in October/November (the Taurids South and Taurids
North - see the end of the article), and a daytime appearance in June
(Beta Taurids). Both meteor showers are linked. The Taurids South and
Taurids North are what Earth encounters as the Taurid meteor stream
heads towards perihelion, whilst the Beta Taurids are encountered as the
meteor stream heads away from perihelion.
Unlike the most prominent annual meteor showers, the Taurids are not
known for being spectacular because the stream is too broad. Whatever
caused the Taurids must have been huge, as it was suggested many years
ago as the primary source for dust in the inner Solar System. It is
argued that comet Encke itself is a fragment of this larger, inactive
comet.
Such a scenario implies that there are other objects in the Taurid
stream, much larger than dust, that are unobserved because they are
inactive. Is there any evidence for large objects in the Taurids hitting
Earth in recent history? Consider the following:
Obviously, given the presence of comet Encke, and the additional fact of
various known Apollo-class asteroids which are observed to have orbits
that resemble those of the Taurids, there is more in the Taurid meteor
stream than just dust. According to Duncan Steel, some of the discovered
Apollo-class asteroids that are in the Taurid meteor stream have
diameters in excess of one kilometre. How many other Tunguska-type
bodies are in it? Are they isolated, or do they exist in swarms?
Meteor streams orbit the Sun, like the planets, but their orbits tend to
be perturbed by the planets. The astronomers calculated how the orbit
of the Taurids has changed over the centuries.
In "Lessons from Jupiter" (Southern Sky magazine, January/February 1995), Clube and David Asher wrote:
Chinese historical records of AD 540 say:
The calculations for the Taurids suggest that we pass through the core
of the meteor stream approximately every 2,500 years - today, we are
passing through the outer edges. The last two occasions when we passed
through the core were in 2200 - 2000 BC and in AD 400 - 600. The epoch
around AD 3000 looks like being a fun time too - the Y2K doomsayers can
always say they just got the millennium wrong.
In 1983, the orbiting IRAS infra-red satellite discovered cometary
"trails" (not tails), representing debris along the path of various
short-period comets. These trails consist of debris, most of which would
be microscopic in size, but how many large objects are there in the
trails? If there are many large objects in these trails, then Duncan
Steel notes in his above-mentioned book:
Concluding Thoughts
Ben Rudder, an anthropologist who reviewed in New Scientist magazine a recently published book by Baillie on the subject, wrote:
Baillie himself notes that:
In their book The Origin Of Comets, Bailley, Clube, and Napier write:
Some of these ideas you may have heard of before. In the 1950s, Immanuel Velikovsky published a number of books, in particular Worlds In Collision,
which suggested that a huge comet had come near to Earth, and had
indeed settled into an orbit around the Sun between Mercury and Earth.
Velikovsky was claiming that Venus was a large comet!
Naturally, his ideas were rubbished. They had no scientific foundation.
The problem today, as Duncan Steel notes, is that astronomers have
become so entrenched in their rightful criticism of Velikovsky's
nonsense, they are rejecting today's scientifically-founded discoveries
that the myths and records of ancient civilisations may contain
important information about what was happening in the sky.
Only now are we seriously contemplating the view that "near-Earth space"
is anything but safe. Is it possible that the ancients were not
entirely ignorant in their beliefs of the appearance of comets being a
bad omen? Fragments hitting the ground would cause earthquakes and blast
damage, as well as start forest fires (fire storms?) and perhaps
volcanoes - which in turn would amplify the environmental effects
through the release of soot into the air. Fragments hitting the water
would generate tsunamis which would flood coastal and inland regions.
Would it surprise you to learn that, according to Baillie, the ancient
Celtics had an oath which translates as:
In "Lessons from Jupiter", Clube and Asher wrote:
If our eyes weren't opened to the danger of fragmenting bodies after we
saw Shoemaker-Levy 9, they should be now. Observatories are conducting
surveys of the sky to discover and track near-Earth asteroids. The
consensus of the astronomical community, however, still remains that the
threat to Earth comes from random asteroids and comets. The idea of the
inner Solar System being different now to from what it was 50,000 years
ago has not been widely accepted. Nevertheless, more astronomers are
open to the dangers associated with an object (currently known or to be
discovered) that fragments in the future. Dealing with any incoming
fragments, however, still remains a problem. You might think that
"planetary defence" is a recent idea. Yet, readers of the poetry of Lord
Byron might be interested to know that in 1822, when he was living in
Pisa, he wrote:
An Observing Postscript
Although Comet Encke is only visible every 3.3 years (it returns next
year), we can observe the Taurid meteor stream every year. As mentioned
above, they have a broad display rather than a well-defined peak.
Although their activity spans the period 1st October to 25th November,
there are two separate maxima. The Taurids South maximum lasts for about
a week around 5th November, while the Taurids North maximum similarly
lasts for about a week around 12th November - the two virtually overlap
each other to produce a plateau.
The rates aren't high (at best, about 5 per hour) but they are easily
seen, slow moving, and they have a reputation for producing very bright
fireballs - a fact that has apparently been observed for thousands of
years! The Taurids are visible during this period from late evening
onwards, and with New Moon occurring on Monday 8th November, there will
be no moonlight interference - the shower is well timed for the
Society's monthly star party at Wiruna. Regardless of whether you're at
Wiruna or elsewhere, if the weather is good, why not step outside and
keep an eye on the sky - it will only be a week or two before the
Leonids.
One thing is for certain: debris from the Solar System does hit Earth.
If it didn't, we wouldn't see meteors every night! The astronomical
community (in particular, those who specialise in comets and/or
asteroids) is not yet convinced as a whole about the notion of the inner
Solar System currently suffering from periodic bombardment from the
remains of a fragmented giant comet. Nevertheless, David Morrison,
principal author of NASA's Spaceguard Survey Reports in 1992 and 1995,
and a critic of the British viewpoint, does admit that:
Regardless of whether the specific theories referred to in this article
turn out to be correct, observing comet debris hitting Earth's
atmosphere now seems to take on a whole new perspective in our
"enlightened ages".
Australia: The Truth is Out There
Everyone in the south-west yesterday had their own big bang theory.
Was it an earthquake? Did Tower Hill erupt into action? Did a meteor shower crash to earth, or was it an alien invasion?
The "big bang" was heard about 1am yesterday, with reports of an "explosion" shaking homes in Winslow, Warrnambool and Terang.
"The whole house shook and there was an almighty noise, like a roar," one Warrnambool resident said yesterday.
"It had my curtains moving and set my car alarm off."
The noise was said to be accompanied by flashes of light that were
variously described as being pink, orange and yellow, and seen as far
away as Mortlake and Heywood.
Perry Vlahos, media liaison for the Astronomical Society of Victoria
(ASV), said it was likely that the bang and the flashes of light were
caused by a meteor.
"It was most likely a meteor exploding in the atmosphere," Mr Vlahos said.
"(The sound) could be a sonic boom or (a meteor) coming through the
atmosphere and exploding. Even though these flashes or sound appear
close, it might be quite a distance above our head."
Don Ward, an ASV member from Gorae West, said the cloudy conditions would have made it difficult to spot a meteor.
"But this talk of lights suggests it might have been an
explosion above the cloud level and it illuminated the clouds," Mr Ward
said.
"(As for the bang), you would get that as the meteor reached a certain
level and the air resistance and friction results in disintegration.
Then if it falls to earth in pieces, that is what we call a meteorite."
Mr Ward said a lack of meteorite pieces or a smoking crater did not
invalidate the theory, as the meteor could have turned to ashes, or they
could have gone into the sea.
The Standard confirmed that it wasn't an earth tremor, with
Geoscience Australia reporting that no seismic activity had been
recorded in the region.
In the absence of a definitive answer - and without any reports of
damage - rumours, pranksters and conspiracy theorists began swirling
early yesterday.
A tsunami was heading towards Lady Bay, an earthquake recording 5.3 on
the Richter Scale caused "extensive minor damage" and a passing defence
force plane had created a sonic boom.
Some seriously questioned if it was alien life or a sign pointing towards a looming apocalypse.
On The Standard's online poll, which had attracted more than
1100 responses last night, more than half thought the "big bang" was
from visiting extraterrestrials.
Scientists find asteroid with potential power of 15 atomic bombs. Heading this way. Tonight.
News.com.au
Amateur astronomers across the world have fallen for a cheeky asteroid that passed the Earth on Monday night.
Asteroid 2011 GP59 was caught winking at our planet from a distance away barely 10 times that of the moon.
The "winking" bit which is getting spacefans so hot and bothered stems
from the fact that the asteroid is cigar-shaped and spinning madly
end-to-end, comparatively speaking.
"Usually, when we see an asteroid strobe on and off like that, it means
that the body is elongated and we are viewing it broadside along its
long axis first, and then on its narrow end as it rotates," said Don
Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet
Propulsion Laboratory in Pasadena, California.
"GP59 is approximately 50m long, and we think its period of rotation is about seven-and-a-half minutes.
"This makes the object's brightness change every four minutes or so."
Don't believe Don? Check out Essex star-botherer Nick James's video of 2011 GP59 cruising past some 3,356,000km away.
That's about 10 lunar distances - our moon is 384,400km away - but tomorrow morning, about 5am, things get a little crazy.
For start, Monday's night's discovery of GP 59 was just that - a discovery.
It was picked up by astronomers at the Observatorio Astronomico de
Mallorca in Andalusia, Spain, who've since determined that it's heading
towards us.
Tonight, it will pass just outside the moon's orbit - again,
comparatively speaking because this is space, folks - at a distance of
533,000km.
However, Mr Yeomans, whose office is responsible for a program called
Spaceguard, which tracks and characterises asteroids and comets and is
supposed to protect us from this sort of thing, says there's no need to
be concerned.
"Although newly discovered, the near-term orbital location of asteroid 2011 GP59 can be accurately plotted," he said.
"There is no possibility of the small space rock entering Earth's atmosphere during this pass or for the foreseeable future."
Which is good news, because although 50m might sound smallish, it's
still five times bigger than an asteroid that exploded 15km above
Indonesia in October, 2009.
That blast released as much energy as three atomic bombs, according to New Scientist, who are supposed to know about such things.
Take comfort in the fact that in 2009, no one saw that asteroid coming.
At least we were given three days' notice this time around.
So that's something.
US: Happen to see the April 9th Fireball?
In my time watching the skies, I've seen quite a few meteors,
fireballs, and bolides. The truly notable ones are few and far between,
but last Saturday, I caught one that was among the most interesting I've
seen. It was a slow moving, bright green one with a nice smoke trail
that was easily as bright as Venus from where I saw it in the suburbs of
St. Louis. I tweeted about it briefly but didn't think much more about
it until I got a response from another person that saw it along with a
link to a collection of observations. As nice as the observation was for
me, it was nothing compared to the view some others got.
Heading over to the American Meteor Society
page for a meteor around this time, it looks like a meteor matching
the one I saw generated a pretty good number of reports from across the
country. Several have reactions similar to my initial one: This must be a
firework. Many reports confirm the smoke trail and fragmentation as
well. But the reports that are really fantastic are the ones from
Canada.
At the Lunar Meteorite Hunters blog,
several reports have been collected. Several of these reports from
various locations in Ontario report the meteor being as bright as a full
moon and lighting up the entire sky! One even notes that they could
hear a fizzling noise, a rare phenomenon thought to occur when the
passage through the atmosphere creates an ionized path that interacts
with the Earth's magnetic field creating radio waves that could induce
physical vibrations in the air around the observer. Another comment
reports a sonic boom around the same time (although sonic booms would
occur well after the meteor was visible due to the sluggish nature of
sound waves, much like the delay between lightning and thunder).
It doesn't look like NASA's All Sky Fireball Network caught this fireball, but an amateur observatory equipped with an all sky camera for detecting fireballs did catch the event.
The green color for such meteors is uncommon but not unprecedented. The
presence of magnesium ions is responsible for this color. Interestingly,
another famous meteor, the Peekskill meteor,
also had a green color and rivaled the full moon in brightness. This
meteor became famous because it was independently captured in at least
sixteen videos (here's one showing the green tint) as well as for surviving intact to the ground and damaging a car.
Meteors of this intensity are quite rare but bright fireballs like this
seem to peak around the vernal equinox. In the weeks surrounding that
day, the rate of such events increases around 10-30%.
Astronomers Study Unusual Asteroid
You've heard of Pluto, once a full-scale
planet that astronomers now classify as a dwarf planet. Now meet 4 Vesta
-- or Vesta for short -- an asteroid that may not be a real asteroid.
The 330-mile diameter object sits in the asteroid belt, a collection of
large and small pieces of rubble that circles the sun between the orbits
of the planets Mars and Jupiter. But Vesta, numbered 4 because it was
the fourth member of the asteroid belt to be discovered, is larger than
most of its asteroid companions and also differs from them geologically.
An unmanned NASA spacecraft called Dawn is now heading for Vesta to explore those differences.
"There are at least two classes of objects that have been called
asteroids," said Thomas McCord, director of the Bear Fight Institute in
Winthrop, Washington. "The real asteroids are broken up pieces of rock
100 kilometers (62 miles) in diameter or smaller. The others are more like small planets."
In addition to Vesta those others include Ceres, the largest asteroid
and first to be discovered, and Pallas, the second asteroid to be
spotted. Ceres is now classified as a dwarf planet like Pluto.
However, Vesta is unique in several respects. It is denser than Ceres and Pallas. It also appears to be differentiated into a rocky surface and an iron core,
like the terrestrial planets Earth, Mars, and Venus. And it is
continually shedding material from its surface as a result of collisions
with small asteroids.
"There are little pieces of Vesta all over the asteroid belt," said Tim
Spahr, director of the Minor Planet Center at the Harvard-Smithsonian
Center for Astrophysics in Cambridge, Massachusetts.
Astronomers have already had a close-up view of some of those pieces
because some of them have landed on the Earth's surface as meteorites.
Scientists recognized their provenance by studying their spectra, which
indicates their chemical composition, and comparing them with Vesta's
spectrum.
Ceres and Pallas, which differ from Vesta geologically, shed less
debris. "Whatever they are made of doesn't travel well," said
Christopher Russell, professor of geology at the University of
California, Los Angeles.
Telescope observations by McCord in 1972 revealed that Vesta's surface
consists of a rock called basalt, which on Earth is made from cooled
magma.
"The basalt would make it unique in that category of objects," Spahr said.
"We think of it as a very large asteroid that is very Earthlike -- called Vesta, the smallest terrestrial planet," Russell said.
Astronomers believe that Earth and similar planets formed when a series
of small bodies coalesced. "We think that these bodies were around in
large numbers and came together to build planets," Russell explained.
McCord added that the problem with Vesta is that "it didn't find a
companion to become a piece of a bigger object that would coalesce with
other companions." So it remained by itself, a kind of time capsule from
an early era in our solar system.
Russell oversees the Dawn mission with McCord as a co-investigator. Dawn
is scheduled to reach Vesta in July and spend a year in orbit, using an
infrared spectrometer, a camera, and a gamma ray detector to explore
Vesta's composition.
The team expects to determine whether basalt uniformly covers Vesta's
surface and where on the surface meteorites originate. The mission will
also probe a large crater in Vesta's southern hemisphere that has
exposed its interior.
"If it is really differentiated, we would see minerals at depths similar to what we see in the Earth's mantle," McCord said.
When it leaves Vesta, the Dawn mission will travel to Ceres, which is larger, rounder, and wetter than Vesta.
By studying the contrasts between the two objects, astronomers hope to
obtain clues to the ways in which the terrestrial planets evolved.
"We're going to try to understand what the building blocks of the early
solar system were like," Russell said. "It's really about tracing our
family tree and understanding where we come from."
Will the findings lead astronomers to reclassify Vesta? Probably not. At
the same 2006 meeting where Pluto was demoted to minor planet status, Vesta was designated one of 269,644 minor planets.
"It was given minor planet number 4, and nobody has worried about [its classification] since," Spahr said.
Comment: Could these protoplanet asteroids be
formed under electrical heating conditions described by James McCanney's
Comet Capture Theory of Solar System formation? For further reading
see:
Planet-X, Comets and Earth Changes by J.M. McCanney
'Impact: Earth!' Asteroid, Comet and Damage Simulation Website
Gather.com
Purdue
University has created "Impact: Earth!," a website where anyone can see
the simulated effects when a comet or asteroid of variable size,
density, and speed hits Earth. Many people believe that asteroid and
comet impacts have played a major role in the history of Earth, and
Purdue has provided us with an inside look at how previous impacts might affect us today.
The Interactive website is said to be scientifically accurate enough to
be used by many different branches of the government including NASA and
the Department of Homeland Security.
Comment: Now we feel much more "reassured" to know
that NASA and the Department of Homeland Security are using the
simulation, and yet don't give the topic its deserved urgent attention.
Unless, of course, they are using the program to calculate the best
location for their private underground bunkers.
It is also user-friendly and visual enough
to be used by schools as an interactive teaching aid for elementary
students. This adds a possible new and exciting way for kids to be
physically hands on and learn about the earth and how impacts might
affect us.
The "Impact: Earth!" simulation and report
were written by Gareth Collins, H. Jay Melosh and Robert Marcus, all
experts in various fields. They go on to say "There have been big
impacts in the past, and we expect big impacts in the future. This site
gives the lowdown on what happens when such an impact occurs." The team
has also answered requests and factored in Tsunamis brought on by
impacting comets or asteroids. There are also plans in the works to
connect the program with Google Earth to show a map of the effects.
Singapore - Rare Sight: 'Fireball' Streaks Across Evening Sky
Stomp
Two STOMPers caught sight of what seemed to be a meteor streaking across the sky last evening (Apr 17).
JJ123, one of the STOMPers who saw the meteor, said:
"My friend and I were on our way to dinner when we chanced upon something unusual in the sky.
"Initially, we tried to convince ourselves that it was an aeroplane
flying across the sky. After much observation, we realised that it
seemed more likely to be a meteor falling from the sky.
"It was definitely a rare sight in the heartlands. Photographs of the
incident were captured in Chong Pang, right in front of the Nee Soon
Camp in the evening."
Another STOMPer Diyar, who also spotted the meteor, said:
"I saw a flame-like object in the sky. It was moving, and I had to run
into a clearing to get a shot of it on my silly iPhone cam.
"And when I tried to get a second shot, it disappeared.
"It would be nice if it were Superman's pod."
More Images
US: New Mexico Fireball
US: "Ripping Fireball" over New Mexico
Thu, 07 Apr 2011 14:08 CDT
Space Weather
© Unknown
"There
was a rippingly fine fireball over north central New Mexico on April
5th at 01:50 am MDT," reports amateur radio astronomer Thomas Ashcraft.
"Signals from distant radio stations bounced off the meteor's trail as
it shredded the ionosphere. Here is a movie I made with the radio echo in stereo at two frequencies. The full radio reflection lasted more than two minutes."
US: Tennessee Fireball Caught on Video
Thu, 07 Apr 2011 23:47 CDT
SpaceWeather
Space rocks have landed in Tennessee. That's the conclusion of
researchers who recorded a brilliant fireball streaking over the Smoky
Mountain state on Wednesday evening. Bill Cooke of NASA's Meteoroid
Environment Office reports: "On April 6th at 8:21:57 CDT, NASA all-sky
meteor cameras detected a very bright fireball moving north across the
state of Tennessee. First detected 52 miles above the Arnold Air Force
base near Tullahoma, the meteor was brighter than crescent Moon and was
approximately 2 feet in diameter, with a weight of 200 lbs. It was last
recorded 30 miles above the town of Woodbury, Tennessee, moving at a
speed of approximately 9 miles per second (32,400 mph)."
Cooke continues: "The NASA Meteoroid Environment Office has reasonable
confidence that some fraction of this meteor survived to the ground as
one or more meteorites. Calculations are underway to determine the
general impact location, which may lie close to the Kentucky border.
Eyewitnesses to the fireball are encouraged to make a report to the American Meteor Society or to the Meteoroid Environment Office."
The smart cameras of Cooke's fireball network are able to
calculate the orbits of incoming fireballs and backtrack their
trajectories into the solar system. "The orbit of this interloper
indicates that it came from the Asteroid Belt, with an aphelion well
beyond the orbit of Mars."
Match made in heaven: Earth finds new companion as giant asteroid joins its path around the sun
Thu, 07 Apr 2011 08:55 CDT
The Daily Mail
But this asteroid orbits the sun in a highly unusual horseshoe pattern.
Earth has found a new companion that has joined its orbit around the sun, scientists have revealed.
It may not have the most romantic of names, but Asteroid 2010 SO16 could
pursue Earth for anywhere between the next 120,000 to a million years.
And at a few hundred metres across, it is the largest space rock ever discovered so close to earth.
© NASA
Very
unusual: Rather than follow its new friend all the way round, SO16
orbits the sun in a horseshoe shape, playing a constant game of catch up
with Earth
Very
unusual: Rather than follow its new friend all the way round, SO16
orbits the sun in a horseshoe shape, playing a constant game of catch up
with Earth
But there is something unusual about SO16, say Apostolos
Christou and David Asher who discovered the giant floating rock last
September at the Armagh Observatory in Northern Ireland.
Rather than follow its new friend all the way round, SO16 orbits the sun
in a horseshoe shape, playing a constant game of catch up with Earth,
they say.
The closer to the sun an object is, the faster it will orbit.
So when SO16 entered the sun's orbit, it was further away than Earth and therefore slower.
When Earth finally caught up with the asteroid, instead of overtaking
it, its gravitational pull drew it closer to the sun sending it back
round at a faster pace.
© Image Source/Corbis
Match made near heaven: Asteroid 2010 SO16 could pursue Earth for anywhere between the next 120,000 to a million years
Match made near heaven: Asteroid 2010 SO16 could pursue Earth for anywhere between the next 120,000 to a million years
Now
quicker than Earth, SO16 speeds round its shorter orbit until it
catches Earth again and is this time pulled away from the sun, slowing
it down.
More simply, from the point of view of the Earth, the asteroid has a
horseshoe-shaped orbit, constantly moving towards and away from the
Earth without ever passing it.
But from the asteroid's point of view, it orbits the Sun continuously in
the same direction, more quickly in smaller orbits and more slowly in
bigger ones.
Christou and Asher say this process is repeated over and over again until the asteroid dies.
At the moment SO16 is travelling at one of its closest approach points
and will be visible in the evening sky for several decades to come.
A Different Kind of Catastrophe - Something Wicked This Way Comes
© Comet Storm
Tunguska Blast
Tunguska Blast
In June 1908, an explosion rocked a remote, swampy area in central
Siberia, in Russia; it came to be known as the "Tunguska event." A later
expedition to the site found that 20 miles of trees had been knocked
down and set alight by the blast. And today, it is understood that
Tunguska's devastation was caused by a 100-foot asteroid that had
entered Earth's atmosphere, causing an airburst.
Some 13,000 years earlier, just after the end of the last ice age, the
Earth's climate had begun to warm up to temperatures like we enjoy
today, when an occurrence thought by some researchers to be an
extraterrestrial impact set off an "impact winter". And caused a return
to ice age conditions that lasted another thousand years, or so. The
"Younger Dryas event," as it is known, coincided with the end of the
prehistoric Clovis culture. And the mass extinction of almost all of the
giant animals that lived on North America at the time.
Before the Younger Dryas event, much of north America had an ecology
similar to what we see today in the lush African savanna. And after the
YD event more then 35 genera had vanished. The giant sloth, short faced
bear, dire wolves, saber toothed cats, a species of camel, horses, and
two species of elephant were wiped out by the YD event. And that's just
the short list. All of that astonishing biodiversity was blown away.
Perhaps the single most important paper on the subject of the Younger
Dryas, is the 2007 paper by R.B. Firestone et al, and titled: Evidence
for an extraterrestrial impact 12,900 years ago that contributed to the
megafaunal extinctions and the Younger Dryas cooling.
In that paper, a team of twenty six scientists, studying sedimentary
deposits presented a whole suite of compelling evidence for a massive
impact event of a comet that appears to have broken up, and scattered,
fragments all across North America. The multiple, air bursts are thought
to have triggered wide spread bio mass burning on a continental scale.
As well as causing a return to ice age conditions, and the extinction of
many species. Including the mega fauna like mastodons, wooly mammoths,
and giant sloths.
That paper caused a pretty good stir in the academic
community. And it has become the 'Flagship', so to speak, of the Younger
Dryas impact hypothesis. But while they had good evidence from the
ground that a very large impact had occurred in the recent past, it was
clear that the event was vastly different from anything that had been
studied before. And without an astronomical model that could confidently
describe the nature of the impactor/s, they were were at an impasse.
"Where's the crater?" became a rallying cry of opponents to the
hypothesis.
But in fact, impact research is an infant science. Who is to say what a
full suit of impact markers should be? And what of airburst blast
effects? Who says the event had to produce a crater?
Tunguska of 1908 was the largest impact event in recorded history. And
yet, the blast affected materials at ground zero do not qualify it as an
impact structure. Indeed, if there hadn't been any eye witnesses, our
impact scientists would be in complete denial of an ET origin for all
the violence there that day. There is no reason to think Tunguska was an
isolated event. Or even a big one, on the grand scale of such things.
At Sandia Labs, Mark Boslough used their 'Red Storm' supercomputer to
simulate the airburst and impact of a 120-meter diameter stony asteroid.
The colors in the simulation we see below are graded by temperature.
White = 5800K; Red = 2000K. Dr Boslough tells us that, in it, we see
the ablated meteoritic vapor mixes with the atmosphere to form an opaque
fireball with a temperature of thousands of degrees. As it hits the
ground, the hot vapor cloud expands to a diameter of 10 km within
seconds, remaining in contact with the surface, with velocities of
several 100m/s. And at temperatures exceeding the melting temperature of
quartz for more than 20 seconds. Moreover, the air speed behind the
blast wave exceeds several hundred meters per second during this time.
For comparison, an ordinary oxy-acetylene cutting torch in a steel shop
uses a thin stream of hot gases at only about 900 degrees C. and 40PSI
to cut steel. The speed of that stream of hot gasses is only a little
bit more than a stiff breeze. But that's all it takes to turn solid iron
into a melted, aerosol, spray. And to blow it away in runnels of melt
into heaps of slag.
Dr Boslough tells us that: "Simulations suggest strong coupling of
thermal radiation to the ground, and efficient ablation of the resulting
melt by the high-velocity shear flow."
We have its existence predicted in peer reviewed literature. But so far I
haven't heard anyone attempt to describe the form that such
geo-ablative melt might take as it is emplaced. While in motion, any
ablated materials from a large, geo-ablative, airburst like that would
be in atmospheric suspension, in a density current similar to a
pyroclastic flow. And when everything comes to rest, the resulting rock
form might be visually indistinguishable from ordinary volcanic tuff, or
ignimbrite. If so, we face a conundrum in the Earth sciences. Because
it has always been assumed without question that only terrestrial
volcanism can melt the rocks of the Earth, or produce 'Tuff'.
If very large airbursts can produce formations of geo-ablative melt,
instead of craters, then almost every last pebble of airburst melt on
this fair world of ours has been mis-defined as volcanogenic.
Astronomers Victor Clube, and William Napier, had been talking about the giant comet they described as the progenitor of the Taurid Complex since 1982, in their book The Cosmic Serpent.
But no one had connected the dots, and put the Younger Dryas comet, and
the Taurid Progenitor together. Except in private, speculative, emails,
and letters. And to the best of my knowledge there was nothing in
refereed literature.
Then, In early 2010 Professor Napier published a paper in the Journal Monthly Notices of the Royal Astronomical Society titled, Paleolithic extinctions and the Taurid Complex in it we read:
"The proposition that an exceptionally large comet has been undergoing
disintegration in the inner planetary system goes back over 40 years
(Whipple 1967), and the evidence for the hypothesis has accumulated to
the point where it seems compelling. Radio and visual meteor data show
that the zodiacal cloud is dominated by a broad stream of largely
cometary material which incorporates an ancient, dispersed system of
related meteor streams. Embedded within this system are significant
numbers of large NEOs, including Comet Encke. Replenishment of the
zodiacal cloud is sporadic, with the current cloud being substantially
overmassive in relation to current sources. The system is most easily
understood as due to the injection and continuing disintegration of a
comet 50-100 km in diameter. The fragmentation of comets is now
recognized as a major route of their disintegration, and this is
consistent with the numerous sub-streams and co-moving observed in the
Taurid complex. The probable epoch of injection of this large comet,
~20-30 kyr ago, comfortably straddles the 12.9 kyr date of the Younger
Dryas Boundary.
The hypothesis that terrestrial catastrophes may happen on timescales
~0.1 Myr, due to the Earth running through swarms of debris from
disintegrating large comets, is likewise not new (Clube & Napier,
1984). However the accumulation of observations has allowed us to build
an astronomical model, closely based on the contemporary environment,
which can plausibly yield the postulated YDB catastrophe. The
interception of ~1015 gm of material during the course of disintegration
is shown here to have been a reasonably probable event, capable of
yielding destruction on a continental scale.
The object of this paper is not to claim that such an encounter took
place at 12,900 BP - that is a matter for Earth scientists - but to
show that a convincing astronomical scenario can be constructed which
seems to give a satisfactory match to the major geophysical features of
the Younger Dryas Boundary data.
If indeed the YDB event was an astronomical catastrophe, its occurrence
bears little relation to current impact hazard assessments derived from
NEO surveys."
It was indeed an astronomical catastrophe. And the nature of the event
bears no resemblance whatsoever to anything in any NEO hazard
assessments, or anything in current impact theory.
With Professor Napier's work specifically proposing in refereed
literature that the Taurid Progenitor was the Younger Dryas comet, he
changed the game completely. Because he didn't just give us a convincing
astronomical model of the event. We also have a pretty good picture of
the physical properties of the thing that did the disastrous deed. And
if you can describe a beast, you can predict its footprints.
It is important to note here that the astronomical model of the Taurids
implies that most catastrophic impact events are probably the result of a
very large cluster of smaller fragments, and cometary debris. And not a
single, large bolide.
Mark Boslough's simulations predict the temps, pressures, flow
directions, and rotation speeds, of a single impact down-blast vortex.
And since we are working from postulate that the events of the YDB were
caused by the impact storms, of the debris streams, of the fragmented
Taurid progenitor. The YD impact hypothesis as it stands, describes tens
of thousands of such airbursts in a little over an hour. And
accompanied by clouds of particles down to the size dust grains falling
into the atmosphere at something like 30 km/per second, as the Earth
crossed through the orbital path of the giant fragmented comet's debris
stream.
Firestone, and friends proposed destructive forces equivalent to as much as 109
megatons of TNT. And at temps hotter than the surface of the sun. (a
half pound of TNT will blow a hole in the ground you could lose a small
car in)
Professor Napier states "The interception of ~1015 gm of
material during the course of disintegration is shown here to have been a
reasonably probable event, capable of yielding destruction on a
continental scale." Using a gram scale to weigh a giant comet is like
giving the distance to moon in inches. The total mass of the fragments
that hit the Earth that day works out to well over 1.1 billion tons. 109 mega tons TNT of destruction doesn't seem like such a stretch, when you work out how big the parent comet was.
© CraterHunter
Comet Linear
Comet Linear
The Deep Impact
mission to comet TEMPEL 1 showed the head of that comet to have the
consistency of a dirty snow bank. It also showed that the object is a
geologically active body. Comet HOLMES is unstable, and prone to violent outbursts. Comet LINEAR,
and Comet Scwassmann-Wachmann 3, shown here make it abundantly clear
that total, explosive, fragmentation of a comet can occur spontaneously
at any time. And it can happen before it even gets close to a planet. It
doesn't need the atmosphere to do that.
If you can describe a beast, you can predict its footprints. Since the
YD impact hypothesis has become a fully fledged theory that gives a
specific description of the exact nature of the impactors, then it
follows that we should also be able to predict the nature, and severity,
of the blast effected materials. Only the first fragments to fall would
have fallen into cold atmosphere. The rest would have fallen into
already superheated atmosphere, and just cranked up the heat, and
pressure. So we're not necessarily looking for craters where solid
bolides hit the ground. We are looking for the signatures, whatever they
might be, of a 'Perfect Storm' of ablative airbursts, with winds
gusting to supersonic, and downdrafts hotter than the surface of the
sun. In the impact zones, the surface of the Earth didn't get smashed
and broken by the event. It was flash melted, and blown away.
Extraordinary hypotheses require extraordinary proofs. If the Younger
Dryas Impacts were, in fact, the multiple airburst impact storms of the
Taurid Progenitor, then there should be hundreds of thousands of cubic
miles of flash melted rock, and blast effected materials, on this
continent, as pristine as the day they first cooled. And with no giant
volcanic system to account for them. And in fact, such continental
scale, orphaned materials do indeed exist. And they can be found in two
large geologically recent, multiple airburst, impact zones. One is The Northeast Impact Zone,
extending from the Great Lakes to the Arctic circle. And the other
major impact zone can be found in central Mexico, and extends up into
west Texas, and New Mexico.
The Chihuahuan Ignimbrites of central Mexico
have always been a mystery as to their source. Generations of
geologists have assumed they must be volcanogenic. And one typically
hears the excuse that it could take decades to find the vents, and magma
chambers it all came from. But of more than 350,000 cubic miles of
pristine pyroclastic materials in the Chihuahuan Desert, and the Sierra
Madre Occidental mountains, less than 15% can be attributed to a
volcanic system. And when we use modern high resolution satellite
imagery to view the typical Airburst Impact structure
at 29.702168, -105.686617 we can see why. That structure, and the
geo-ablative curtain of airburst melt surrounding it, is typical of more
than 50,000 square miles. And terrestrial volcanism had nothing to do
with it.
© CraterHunter
Comet Scwassmann-Wachmann 3.
Comet Scwassmann-Wachmann 3.
The high resolution satellite imagery that's become available in the
past decade has revealed a new perspective that hasn't been available
to geologists of the past. Answering the question of where those
pyroclastic materials came from is easy when you can read the patterns
of movement, and flow, that were frozen in time from the moment of their
emplacement. And as easily as following splashes of spilled paint back
to a can.
The most startling revelation will come from studying those perfectly
legible patterns of flow. And when you realize that gravity pulling them
down a slope, and away from a vent, was not the motive force while they
were in motion. And that you are looking at wind-driven patterns of
movement, and flow, during the emplacement event, like the froth, and
foam on a storm tossed beach. And when you begin to see that those
pyroclastic flows describe a completely different kind of non-volcanic
catastrophe from anything ever imagined before.
What kind of naturally occurring, non-volcanic, event can flash melt,
and ablate, the surface of the Earth, and turn more than 50,000 miles
into a single random colliding, inter-flowing, wind-driven, sheet of
pyroclastic flows, and ablated landforms? Or suddenly blast away a large
section of an ice sheet as big as the continental United States?
Imagine along with me for a moment. What say we take a great big comet,
say 50 to 100 km wide, out of the Oort Cloud, or the Kuiper belt, and
inject it into the inner solar system. And we park it an elliptical,
Earth crossing orbit, and break it up into not so little pieces. Let's
give it enough time for tidal forces to break it up completely, and
stretch it out into a very long debris stream of particles, and
fragments. Our average fragment size was about the size of the Tunguska
object. But they ranged from more than a half mile wide, all the way
down to clouds of dust.
As the Earth's orbit brings it across orbital path of the giant,
fragmented comet's debris streams, the fragments begin to fall into the
atmosphere from the south at a low angle. And more than 30 km/sec. The
first fragments to hit will produce atmospheric temps well over 100,000
degrees C. And they are just cheerleaders, twirling batons in front of a
parade. The rest fall into already superheated impact plasma, and just
crank up the heat, and pressure. In this way, almost 100% of the kinetic
energy of the fragments gets translated to heat, and pressure in the
atmosphere. And that heat, and pressure, hits the ground as an almost
continuous, supersonic, stream of airbursts, hotter than the surface
sun.
With just a few short minutes of that, I'll bet we could sterilize the
whole lush, African Savanna, and make it look just like central Mexico,
and the American Southwest. And in fact, according to the fossil
record, every mega-faunal ecological niche we see in the African
Savanna, and more, is represented in the fossils below the Younger Dryas
Boundary layer. But not above it. All that astonishing biodiversity was
burned, and blown away in seconds.
Sound Crazy? Not so fast. The 2007 Firestone paper cited Toon et al when they proposed temps as high as 107degrees
C. There's that exponential thing again. That's 10 million degrees
Celsius. But Professor Napier pointed out for me that even if a bolide
hits the atmosphere at 30 kilometers per second, and all of its kinetic
energy is translated to heat in the atmosphere, it is difficult to get
more than 100,000o C. But that's ok. Because either way, even
with the more conservative figure, we are still describing temperatures
that are more than enough to vaporize any known substance on the
surface of the Earth. And to blow it away like wax under a high pressure
blowtorch.
A compelling, almost conclusive, case can be made for the argument that
the Younger Dryas cooling, the mega faunal extinctions of the early
Holocene, and the demise of the Clovis people were all caused by the
same event. It was the multiple, thermal airburst, impact showers of
the fragments of the Taurid Progenitor soon after its complete breakup.
And the thermal explosive catastrophe its debris stream brought, was
more violent than anything ever imagined.
In the simulation we see above, Dr Boslough simulated a single bolide.
The blast effected materials of the event describe a giant stream of
fragments such as that, accompanied by clouds of particles down to the
size of dust grains.
No one has ever found a crater that can be dated to the event. But that
much heat, and pressure, only goes away peacefully in children's
bedtime stories. And no craters, does not mean there are no planetary
scars.
Because it was already broken up before the Earth encountered its debris
stream. The atmosphere translated nearly all of the kinetic energy into
heat. But it didn't dissipate it. It transferred the heat directly to
the ground in an almost continuous rain of devastating supersonic,
geo-ablative, down-blasts.
The eastern end of the Laurentide Ice sheet got hit in an area from
Northern Minnesota, and the Great Lakes to the Arctic Circle. When the
first down-blasts of thermal impact plasma hit the Laurentide Ice sheet
they caused titanic, hot and powerful, hydrothermal explosions (steam)
that lofted huge icebergs hundreds of miles in all directions.
A few short minutes later, those flying chunks of ice were the
impactites that formed the thousands of oval depressions all over the
eastern side of the continent called the "Carolina Bays". And the signs
of massive flooding that have been attributed by generations of
geologists to the bursting of ice damns holding back Glacial lake Agassiz are, in fact, the flood effects of the flash melting of major portions of the eastern end of the Laurentide ice sheet.
In a matter of minutes, much of the eastern end of the LIS was
obliterated. Much of which probably went into the atmosphere as steam.
The immense hydrothermal explosions also lofted the iceberg sized chunks
of ice that produced the Carolina Bays when they fell back to Earth.
The other much larger cluster of fragments hit in central Mexico, and
the American southwest. The Earth was probably in the path of the
devastating streams of high velocity, air bursting comet fragments for
about an hour. And out of tens of thousands of large, air-bursting,
fragments there is not one single impact structure that bears any
resemblance to what standard impact theory might expect. Or a "full
suite of impact hallmarks" all of the planetary scarring of the event
has been mis-defined as volcanogenic. And most of the ages of those
blast effected materials have been over estimated by orders of
magnitude.
The most devastating geo-ablative effects were in central Mexico, and
the American Southwest. In seconds all of central Mexico was pulverized
into a surreal, and blasted, landscape of heavily ablated, and melted
terrains, like a Salvador Dali painting. It generated a post impact mega
tsunami of thermal impact plasma taller than the atmosphere, hundreds
of miles wide, and hundreds of miles from front to back, that rushed
downrange to the northwest at supersonic speeds. And it sterilized the
western half of the continent on a swath from Mexico to the Arctic,
along a storm front extending from California to the great plains.
The Mexican cluster of fragments was approximately 500 miles wide. As
the first of the fragments hit they detonated high in the atmosphere.
But the explosions retained their momentum. And they hit the ground as
devastating supersonic down blasts hotter than the surface of the sun.
And as I said, only the very first fell into cold atmosphere. The rest
of the fragments just piled on in, and added to the heat, and pressure.
The overpressures from the blast waves were so powerful they blasted
whole mountain ranges aside like clumps of flour on a bakers table. And
still, they continued to pile in. And the heat, and overpressures,
continued to build.
The blast wind would've incinerated everything it passed over. In the
hottest part of the impact zone, vast quantities of stone were
vaporized, and whipped up into the storm, where the atmosphere worked
like a refining tower. And in a fiery rain the materials precipitated
out of the plasma storm down wind according to their condensation
temperature, and specific gravity. This was like nothing ever imagined
in our most frightening nightmares of disaster, or catastrophe. During
the impacts, and for a few minutes after, most of North America from
Mexico to the Arctic, and from California, to the plains of the Midwest,
was engulfed in what might best be described as a full blown
magneto-hydro-dynamic plasma storm. Like something we should only expect
to find on the surface of the sun. And there is not one square inch of
the surface terrains of western North America in its path that doesn't
bear the scars of that blast of heat.
In fact look closely in modern satellite images. You see that all of the
high ridges of the mountain ranges of California, Colorado, Utah,
Wyoming, and Montana that had glaciers at the time bear clear and
obvious signs of the heat. And a profound feature that is easy to spot
is melted glacial ridges, blown over to the north and northwest like
runnels of melted wax on the side of a candle. And we typically see high
glacial valleys below those melted ridges that have all of the material
that was once suspended in the Glacier lying exactly below where it was
in the glacier. Indicating that the ice evaporated so fast there was no
flow of water down slope to move any of the glacial till. So we see
that the glacial till dropped out so fast it's as if the ice just
vanished in a quick puff of steam.
Almost at the same time Mexico was getting hit, the eastern end of the
ice sheet was getting pounded just as hard. But the ice added another
factor to consider in understanding the blast effects. Under the thermal
airburst down-blasts, the ice reacted explosively, like reactive armor
on a battle tank. The impacts into the ice sheet triggered titanic
hydrothermal explosions that lofted huge berg sized chunks of ice for
hundreds of miles forming the 'Carolina Bays'.
The ice sheet impacts evaporated millions of acre feet of water directly
into the atmosphere. There was probably much more of the ice sheet that
went up as steam, only to rain down in the days, and weeks, that
followed than was melted to flow into the sea. As North America burned,
the storms around the world raged. It rained everywhere for weeks.
Sea levels rose as the blasted, and melted ice sheet flowed in mega
floods to the sea. And just as today, most of the larger populations
would have been in low lying areas. The seas rose too fast or anyone,
and anything, living in coastal areas anywhere in the world, to escape.
Every coastline all over the world was effected. And everywhere it would
have been much like a giant tsunami. But this time, the flood waters
rose and never receded.
Much of an ice sheet bigger than the Continental United States was
destroyed. The whole world was shaken to the core. And, like taking
weight from a floating barge, the sudden shift of the weight of so much
ice caused a massive uplift of the middle of the continent. Coupled with
the powerful detonations of so many exploding comet fragments, it
caused earthquakes, and volcanic eruptions all over the world. And
global seismic activity was the worst in many millions of years.
While the mega floods from the blasted ice sheet were still flowing into
the sea. Most of the biomass of western North America was burned away
and much of the resultant smoke, and soot was blown high above the
atmosphere where it blocked sunlight for years. There was an immediate
sharp drop in temperatures world wide. It was the worst kind of 'Perfect
Storm'. Made all the worse because at the same time the destruction of
the LIS caused a sudden rise in sea levels world wide. It it may have
caused a shutdown of the thermal haline cycle which brings tropical
warmth to the North Atlantic. Be that as it may, Northern Europe quickly
cooled to arctic temperatures. And the cold remained for centuries.
The Clovis people, and whole species, and ecosystems, were annihilated
in seconds. Most of the western half of the continent was incinerated,
and sterilized. The other half was devastated. The food chain of the
entire northern hemisphere was severely compromised. And except for
rare, and random, patches here, and there, that remained somehow
unscathed like the one surviving undamaged house in a neighborhood hit
by a tornado. The lush savannah the giant animals of North America
depended on for food was gone down to the last blade of grass. Those
giant animals that survived in the southeast corner of the continent
faced a drastically altered, and reduced food supply. And they simply
starved. The specialist predators that depended on those animals for
food perished as well. The species that survived extinction were the
most adaptable, the smaller ones that didn't eat much, and those that
were just plain lucky.
If there were any human survivors of that day, anywhere in the western
hemisphere, they were hiding in a deep cave somewhere well south of the
impact zone. And they were cringing in terror as their world was erased
and made new again. Any who peeked out of the cave without getting
themselves killed, may have told stories of fire breathing dragons
remaking the world with breath so hot it could melt mountains.
The progression of the event was a result of the Earth's movement along
its orbital path, as it crossed through the orbital path of the giant
comet's debris stream. Not a product of the Earth's rotation. So that,
in a daytime event, the fragments are outbound from perihelion. The
airburst storms would begin in the west, and progress to the east. As
the Earth Crosses the debris stream. In a night time event, the debris
stream would be inbound towards their perihelion, and the opposite would
be true.
Using modern satellite imagery, a very compelling case can be made that
the scenario described above is very close to the exact truth. The
remaining debris of the Taurid Complex is still out there. And there are
still fragments of significant size in Earth crossing orbits. It is
almost a certainty that the next major impact event will be an airburst.
And it is a certainty that we haven't seen the last catastrophic impact
of the Taurid Complex.
Something wicked this way comes.
US: Bright Fireball Leads To Meteorite Search In Tennessee
Fri, 08 Apr 2011 10:24 CDT
Space Daily
© NASA/MSFC/University of Tennessee Space Institute/Hands-On Science Center
False-color image of a bright fireball meteor over Tullahoma, Tenn., on the night of April 6, 2011.
False-color image of a bright fireball meteor over Tullahoma, Tenn., on the night of April 6, 2011.
Did you see a bright flash in the sky over Tullahoma, Tenn., last night? Have we got a scavenger hunt for you...
At approximately 08:21:57 p.m. CDT on April 6, 2011, NASA all-sky meteor
cameras located at the University of Tennessee Space Institute, in
conjunction with the Hands-On Science Center in Tullahoma, Tennessee,
and at the Walker County Science Center in northwest Georgia detected a
very bright fireball moving north across the state of Tennessee.
First detected 52 miles above the Arnold Air Force base near Tullahoma,
the meteor was brighter than crescent moon and was approximately two
feet in diameter, with a weight of 200 lbs. It was last recorded 30
miles above the town of Woodbury, Tenn., moving at a speed of
approximately nine miles per second, or 32,400 mph.
The NASA Meteoroid Environment Office has reasonable confidence
that some fraction of this meteor survived to the ground as one or more
meteorites. Calculations are underway to determine the general impact
location, which may lie close to the Kentucky border.
Eyewitnesses to the fireball are encouraged to make a report to the
American Meteor Society at www.amsmeteors.com, or to the Meteoroid
Environment Office.
More information will be forthcoming at the completion of the impact
zone calculations, which may take some time. The orbit indicates that
this interloper was from the Asteroid Belt, with an aphelion well beyond
the orbit of Mars.
Earth to Get Very Close Look at a Huge Asteroid
© Arecibo Observatory / Michael Nolan
The
near-Earth asteroid named 2005 YU55 — on the list of potentially
dangerous asteroids — was observed with the Arecibo Telescope's
planetary radar on April 19, 2010, when it was about 1.5 million miles
from the Earth, which is about six times the distance to the moon.
The
near-Earth asteroid named 2005 YU55 — on the list of potentially
dangerous asteroids — was observed with the Arecibo Telescope's
planetary radar on April 19, 2010, when it was about 1.5 million miles
from the Earth, which is about six times the distance to the moon.
Flyby in November sparks extensive campaign for all kinds of observations
Mark your calendars for an impressive and upcoming flyby of an asteroid
that's one of the larger potentially perilous space rocks in the heavens
- in terms of smacking the Earth in the future.
It's the case of asteroid 2005 YU55, a round mini-world that is about
1,300 feet in diameter. In early November, this asteroid will approach
Earth within a scant 0.85 lunar distances.
Due the object's size and whisking by so close to Earth, an extensive
campaign of radar, visual and infrared observations are being planned.
Asteroid 2005 YU55 was discovered by Spacewatch at the University of
Arizona, Tucson's Lunar and Planetary Laboratory on Dec. 28, 2005. En
route and headed our way, the cosmic wanderer is another reminder about
life here on our sitting duck of a planet.
Close and Big
"The close Earth approach of 2005 YU55 on November 8 is unusual since it
is close and big. On average, one wouldn't expect an object this big to
pass this close but every 30 years," said Don Yeomans, manager of
NASA's Near-Earth Object Program Office and the Jet Propulsion
Laboratory in Pasadena, Calif.
Yeomans said that with new radar capabilities at Goldstone in California
- part of NASA's Deep Space Network - there is a good chance of
obtaining radar imaging of 2005 YU55 down to the 5-meter resolution
level. Doing so, he said, would mean obtaining higher spatial resolution
of the object than that attained by recent spacecraft flyby missions.
"So we like to think of this opportunity as a close flyby mission with
Earth as the spacecraft," Yeomans told Space.com. "When combined with
ground-based optical and near-infrared observations, the radar data
should provide a fairly complete picture of one of the larger
potentially hazardous asteroids," he said.
Asteroid 2005 YU55 is a slow rotator. Because of its size and proximity
to Earth, the Minor Planet Center in Cambridge, Mass., has designated
the space rock as a "potentially hazardous asteroid."
Dishing It Out
"We're already preparing for the 2005 YU55 flyby," said Lance Benner, a
research scientist at JPL and a specialist on radar imaging of
near-Earth objects. He said part of the plan is to observe the asteroid
with radar using both the huge Arecibo dish in Puerto Rico and equipment
at Goldstone.
"The asteroid will approach from the south, so Goldstone has the first
chance to observe it due to its declination coverage," Benner told
Space.com.
To help coordinate the observing campaigns, "Radar Observations
Planning" websites have been set up for this unusual occasion, Benner
said.
"This flyby will be the closest by any near-Earth asteroid with an
absolute magnitude this bright since 1976 and until 2028," Benner added.
"Having said that, nobody saw 2010 XC15 during its close flyby within
0.5 lunar distance in 1976," he said, noting that this asteroid wasn't
discovered until late in 2010.
"Thus, the flyby by 2005 YU55 will be the closest actually observed by
something this large, so it represents a unique opportunity," Benner
said. "In a real sense, this will provide imaging resolution comparable
to or even better than a spacecraft mission flyby."
Radar Paint
Benner said that because the asteroid is zooming by Earth so very close,
radar echoes will be extremely strong. One facility at Goldstone will
be used to transmit and "radar paint" the object ... another Goldstone
dish is on tap to snag the reflected echo of radar data.
What Can Radar Do?
Information collected by this technique, for example, can be transformed
into 3-D shapes, with surface features and spin rates identified. The
asteroid's roughness and density also can be assessed. Furthermore,
radar can improve the whereabouts of the object. By greatly shrinking
uncertainties for newly discovered meandering NEOs, that in turn enables
motion prediction for decades to centuries.
As for seeing the asteroid with small telescopes, start getting your gear ready.
Initially, the object will be too close to the sun and too faint for
optical observers. But late in the day (Universal Time) on Nov. 8, the
solar elongation will grow sufficiently to see it. Early on Nov. 9, the
asteroid could reach about 11th magnitude for several hours before it
fades as its distance rapidly increases, Benner explained.
Leonard David has been reporting on the space industry for more than
five decades. He is past editor-in-chief of the National Space
Society's Ad Astra and Space World magazines and has written for Space.com since 1999.
Comment: The reader may be interested in Planet-X, Comets and Earth Changes by J.M. McCanney.
US: Loud Mysterious Sound Heard In Calaveras County, California
Calaveras County Sheriff's Detectives are investigating a loud
explosive sound that was reported in several communities yesterday.
According to the Sheriff's Office, at around 8:50 am, the Sheriff's
dispatch received multiple 9-11 calls from San Andreas, Mokelumne Hill,
Mountain Ranch, Railroad Flat and West Point. All of the callers said that heard a single loud explosion type noise, but there were no reports of fire or smoke being seen and no specific location given.
Several callers also stated that a plane had flown overhead just prior
to the loud explosion and they suspected it was a sonic boom. Sheriff's
Dispatch checked with the FAA and Calaveras County Airport who had no reported planes in distress in the area.
The Sheriff's Office will also follow-up with local military contacts in
an attempt to confirm the possible sonic boom that was heard by many
county residents.
Comment: Sott.net has picked up many reports of similar mysterious booms recently:
Ohio, US: Newark Police Puzzled By Mystery 'Boom'
'Mushroom-shaped light and loud boom' rocks remote Siberia
US: 'Boom' Heard Across Southeast Oklahoma
US: Big Boom Remains a Mystery
US: Mysterious Boom Rocks Region
California, US: Source of Loud Boom Continues to be Mysterious
US: Mystery Sonic Boom Rattles Georgia
US: Mystery Blast Likely a Sonic Boom, Official Says
The Dark Ages: Were They Darker Than We Imagined?
© Unknown
Published in the September 1999 issue of Universe.
As we approach the end of the Second Millennium, a review of ancient
history is not what you would normally expect to read in the pages of Universe.
Indeed, except for reflecting on the AD 837 apparition of Halley's
Comet (when it should have been as bright as Venus and would have moved
through 60 degrees of sky in one day as it passed just 0.03 AU from
Earth - three times closer than Hyakutake in 1996), you may well wonder
what we could learn from any astronomical events that occurred more than
a thousand years ago.
Any history text will say that the Dark Ages refers to the period after
the fall of the Roman Empire in the middle of the 1st Millennium (it was
not sponsored by the International Dark Sky Association). It was a time
when European civilisation stagnated - even that term is a generous
description of the living standards and social setting of the next few
centuries. In a broader sense, however, "Dark Ages" can be applied to a
few eras of social upheaval over the last several thousand years, which
fits in nicely with what you're about to read - stay with me, as the
possible astronomical implications will soon become apparent.
Physical Aspects Of The Dark Ages
Let's first look at the onset of "the" Dark Ages in the sixth century
AD. The Roman Empire was finished, nothing was happening in the
sciences, and worse was happening in nature. The Italian historian
Flavius Cassiodorus wrote about conditions that he experienced during
the year AD 536:
"The Sun...seems to have lost its wonted light, and appears of a bluish
colour. We marvel to see no shadows of our bodies at noon, to feel the
mighty vigour of the Sun's heat wasted into feebleness, and the
phenomena which accompany an eclipse prolonged through almost a whole
year. We have had a summer without heat. The crops have been chilled by
north winds, [and] the rain is denied."
Other writers of the time described similar conditions:
Procopius : "...during this year a most dread portent took place. For
the Sun gave forth its light without brightness...and it seemed
exceedingly like the Sun in eclipse, for the beams it shed were not
clear."
Lydus : "The Sun became dim...for nearly the whole year...so that the fruits were killed at an unseasonable time."
Michael the Syrian : "The Sun became dark and its darkness lasted for
eighteen months. Each day it shone for about four hours, and still this
light was only a feeble shadow...the fruits did not ripen and the wine
tasted like sour grapes."
Was this a local phenomenon? According to the book Volcanoes of the World,
Dr. Timothy Bratton has noted that there was a small eruption of the
volcano Mt. Vesuvius in AD 536. Could this be the cause? It may well
have contributed to the scene (although the eruption was much smaller
than the big one of AD 79), but it can not really account for the
similar conditions that were experienced around the world.
In China, "the stars were lost from view for three months". Records
indicate that the light from the Sun dimmed, the expected rains did not
eventuate, and snow was seen in the middle of summer. Famine was
widespread, and in the midst of the turmoil, the Emperor abandoned the
capital.
Bad luck tends to get bunched together, and thus came the
plague. The Justinian Plague, named after the Byzantine Emperor of the
time, is reported to have begun in central Asia, spread into Egypt, and
then made its way through Europe. By some accounts, it was as bad as the
Black Death which "plagued" Europe in the Middle Ages.
A Different Branch Of The Picture
Mike Baillie is Professor of Palaeoecology at Queens University,
Belfast, Northern Ireland. He is an authority on tree rings and their
use in dating ancient events (every year, a tree adds a "ring" to its
trunk as it grows - good years are represented by thick rings while bad
years are represented by thin rings). He conducted a complete (and
continuous) review of annual global tree growth patterns over the last
5,000 years and found that there were five major environmental shocks
that were witnessed worldwide. These shocks were reflected in the ring
widths being very thin. Wanting to know more, he turned to human
historical records, and found that the years in question (between 2354
and 2345 BC, 1628 and 1623 BC, 1159 and 1141 BC, 208 and 204 BC, and AD
536 and 545) all corresponded with "dark ages" in civilisation.
The minimal growth of trees around 2350 BC has been associated in the
past with the eruption of a volcano in Iceland. Yet, the period in
question is also associated with floods, the creation of new lakes, and
even the start of Chinese history. Furthermore, Marie-Agnes Courty, an
archaeologist from France, has claimed new data regarding a catastrophe
said to have occurred in the Middle East. Samples from three separate
regions all appear to contain a calcite material found only in
meteorites, and analysis of debris show what seems to be a combination
of "a burnt surface horizon and air blast."
Indeed, some 40 cities throughout North Africa, the Middle East, Europe,
and Asia are thought to have been devastated, or even disappeared,
about the same time in a series of catastrophes.
The twelfth century BC is associated with the "Greek Dark Ages", the end
of the Hittite civilisation in the Near East, the end of Bronze Age
Israel, and the end of the Bronze Age Shang dynasty in China. Ancient
Chinese history has the notion of "mandate from heaven", where the
rulers were essentially subject to the whims of the sky above. Strange
sights in the sky would not be seen as good news for Chinese Emperors.
Indeed, around this time, Chinese records speak of:
"...many gods and spirits were annihilated in this battle, and several
stellar dignitaries were replaced by newcomers to the celestial
domains."
What could cause such global shocks? A likely answer, which has a good
fit to the evidence, was what the European and Chinese observers
described at the time as "dragons in the sky" - comets! We're not
talking about an intact large comet (if that had hit in the last several
millennia, we would not be here today), but rather fragments from a
disintegrating comet or asteroid (small pieces like that which hit
Tunguska in 1908). These would throw up dust that would envelope the
world and dim our view of the Sun and skies.
All this sounds like an interesting theory, but is there any evidence
"above us" that fits in with the scenario. How do we account for so many
impacts over the last several millennia when the consensus today in
astronomy is that impacts causing global consequences (mild as well as
major) are very rare?
Enter The Astronomers
Independently of Baillie's studies, British astronomers were putting
together an explanation of the Taurid meteors that we see. The Taurids
are related to comet Encke, as first shown by Fred Whipple, best known
for proposing the "dirty snowball" model of comets. Mark Bailey, Victor
Clube (brother of my rugby coach at school!), and Bill Napier put
forward the theory that Encke and the Taurid meteors originated from a
giant comet that fragmented some 40,000 years ago after entering the
inner Solar System. The idea of a comet splitting up into smaller pieces
is nothing new (witness Shoemaker-Levy 9 in 1994 and the return this
year of the fragmented periodic comet Machholz 2), and indeed Dr. Brian
Marsden of the Smithsonian Astrophysical Observatory is the originator
of the idea that the bulk of sungrazing comets we see come from a large
comet that perhaps originally split a few centuries before Christ, and
has split again - this family of comets is known as the Kreutz
sungrazers.
The astronomers noted that Chinese records of meteor observations over
the last two thousand years revealed significant surges in the number of
meteors observed every few centuries. These tended to be observed at
the same time every year - we now know of them as the Taurids, which has
a nighttime display in October/November (the Taurids South and Taurids
North - see the end of the article), and a daytime appearance in June
(Beta Taurids). Both meteor showers are linked. The Taurids South and
Taurids North are what Earth encounters as the Taurid meteor stream
heads towards perihelion, whilst the Beta Taurids are encountered as the
meteor stream heads away from perihelion.
Unlike the most prominent annual meteor showers, the Taurids are not
known for being spectacular because the stream is too broad. Whatever
caused the Taurids must have been huge, as it was suggested many years
ago as the primary source for dust in the inner Solar System. It is
argued that comet Encke itself is a fragment of this larger, inactive
comet.
Such a scenario implies that there are other objects in the Taurid
stream, much larger than dust, that are unobserved because they are
inactive. Is there any evidence for large objects in the Taurids hitting
Earth in recent history? Consider the following:
- In late June, 1178, an English monk reported the observation by
five men of what is believed to have been an impact on the Moon. The
American astronomer-geologist Jack Hartung has argued that this reported
impact created the Giordano Bruno crater, known to be one of the
youngest craters on the Moon. The timing of this event, late June, is
consistent with the Beta Taurids.
- In his book Rogue Asteroids and Doomsday Comets,
former AAO astronomer Duncan Steel describes the fall of a meteorite on
25th June, 1890 near Farmington, Kansas. Besides its obvious timing with
the Beta Taurids, the meteorite is most notable for being the youngest
meteorite known (in terms of exposure to space). Dating of the meteorite
has revealed it was separated from its parent less than 25,000 years
ago (a factor of ten younger than the next youngest meteorite).
- Tunguska : On 30th June, 1908, a fragment believed to be less
than 100m in diameter exploded over the Tunguska river in Siberia. It is
the most well-known impact we know of in modern times. It is generally
believed that the timing of the impact is consistent with it originating
from the Beta Taurids.
- When the astronauts went to the Moon, they placed seismometers
on the Moon's surface. At the end of June, 1975, they registered their
major series of lunar impacts. The impacts were detected only when the
nearside of the Moon (where the astronauts landed) was facing the Beta
Taurid radiant. At the same time, there was a lot of activity detected
in Earth's ionosphere, which has been linked with meteor activity.
Obviously, given the presence of comet Encke, and the additional fact of
various known Apollo-class asteroids which are observed to have orbits
that resemble those of the Taurids, there is more in the Taurid meteor
stream than just dust. According to Duncan Steel, some of the discovered
Apollo-class asteroids that are in the Taurid meteor stream have
diameters in excess of one kilometre. How many other Tunguska-type
bodies are in it? Are they isolated, or do they exist in swarms?
Meteor streams orbit the Sun, like the planets, but their orbits tend to
be perturbed by the planets. The astronomers calculated how the orbit
of the Taurids has changed over the centuries.
In "Lessons from Jupiter" (Southern Sky magazine, January/February 1995), Clube and David Asher wrote:
"Calculations based on an orbit related to that of P/Encke reveal
intersections with the Earth's orbit around AD 600 and before that AD
400, so that a swarm would have been near the Earth's orbit for a
duration of a few centuries around that epoch, the time of the European
Dark Age. This then is a critical extended period when we might well
expect several multi megaton [explosive] events, indeed a great many if
we consider the globe as a whole. The perspective is evidently one in
which we expect the Roman Empire to have gone into decline owing to
multiple-Tunguska bombardment causing great tracts of land to be
deserted and whole communities or nations to be suddenly dislocated. Of
necessity, the period becomes one of barbaric movements."
Chinese historical records of AD 540 say:
"Dragons fought in the pond of the K'uh o. They went westward....In the places they passed, all the trees were broken. "
The calculations for the Taurids suggest that we pass through the core
of the meteor stream approximately every 2,500 years - today, we are
passing through the outer edges. The last two occasions when we passed
through the core were in 2200 - 2000 BC and in AD 400 - 600. The epoch
around AD 3000 looks like being a fun time too - the Y2K doomsayers can
always say they just got the millennium wrong.
In 1983, the orbiting IRAS infra-red satellite discovered cometary
"trails" (not tails), representing debris along the path of various
short-period comets. These trails consist of debris, most of which would
be microscopic in size, but how many large objects are there in the
trails? If there are many large objects in these trails, then Duncan
Steel notes in his above-mentioned book:
"A large fraction of the objects on Earth-crossing orbits, of all
dimensions, are the daughter products from the break-up of a giant comet
some time during the past 100,000 years, dynamical studies suggesting
around 20,000 years as likely. All that is suggested here is a break-up
similar to that undergone by P/Shoemaker-Levy 9 in 1992, except by a
comet at least 100 kilometres across and in an orbit crossing from
Jupiter to the Earth.
The core of the complex...evolves to have a node near 1 AU every
millennium or so, at which time the Earth is bombarded by many [large]
objects in episodes at certain times of year. It is these events that
dominate the hazard to humankind. Such an episode would last for a
century or two."
Concluding Thoughts
Ben Rudder, an anthropologist who reviewed in New Scientist magazine a recently published book by Baillie on the subject, wrote:
"If Baillie is right, history has overlooked probably the single most
important explanation for the intermittent progress of civilisation.
Worse, our modern confidence in benign skies is foolhardy, and our
failure to appreciate the constant danger of comet "swarms" is the
result of a myopic trust in a mere 200 years of "scientific" records."
Baillie himself notes that:
"There is, I feel, a strong case for the contention that we do not
inhabit a benign planet. This planet is bombarded relatively often. If
this story is correct, we have been bombarded at least three times - and
probably five times - since the birth of civilisation some 5,000 years
ago. And each time, the world was changed."
In their book The Origin Of Comets, Bailley, Clube, and Napier write:
"the destruction and chaos accompanying the fate of the Roman empire
[midway through the First Millennium] was all but total, the almost
complete breakdown of the old order leading to a loss of the accumulated
knowledge and wisdom of antiquity which was far from temporary."
Some of these ideas you may have heard of before. In the 1950s, Immanuel Velikovsky published a number of books, in particular Worlds In Collision,
which suggested that a huge comet had come near to Earth, and had
indeed settled into an orbit around the Sun between Mercury and Earth.
Velikovsky was claiming that Venus was a large comet!
Naturally, his ideas were rubbished. They had no scientific foundation.
The problem today, as Duncan Steel notes, is that astronomers have
become so entrenched in their rightful criticism of Velikovsky's
nonsense, they are rejecting today's scientifically-founded discoveries
that the myths and records of ancient civilisations may contain
important information about what was happening in the sky.
Only now are we seriously contemplating the view that "near-Earth space"
is anything but safe. Is it possible that the ancients were not
entirely ignorant in their beliefs of the appearance of comets being a
bad omen? Fragments hitting the ground would cause earthquakes and blast
damage, as well as start forest fires (fire storms?) and perhaps
volcanoes - which in turn would amplify the environmental effects
through the release of soot into the air. Fragments hitting the water
would generate tsunamis which would flood coastal and inland regions.
Would it surprise you to learn that, according to Baillie, the ancient
Celtics had an oath which translates as:
"We will not move from this place until the stars fall from the sky, the earth quakes and the sea comes over the land."
In "Lessons from Jupiter", Clube and Asher wrote:
"We do not of course deny a general background of [Earth-crossing
asteroids] from the asteroid belt but it is these meteoroidal streams,
harbouring swarms of super-Tunguska debris, which are now perceived as
the source of high-level dust veils and low-level airbursts in the
atmosphere, essentially controlling climate and extinction on Earth and
punctuating the course of evolution."
If our eyes weren't opened to the danger of fragmenting bodies after we
saw Shoemaker-Levy 9, they should be now. Observatories are conducting
surveys of the sky to discover and track near-Earth asteroids. The
consensus of the astronomical community, however, still remains that the
threat to Earth comes from random asteroids and comets. The idea of the
inner Solar System being different now to from what it was 50,000 years
ago has not been widely accepted. Nevertheless, more astronomers are
open to the dangers associated with an object (currently known or to be
discovered) that fragments in the future. Dealing with any incoming
fragments, however, still remains a problem. You might think that
"planetary defence" is a recent idea. Yet, readers of the poetry of Lord
Byron might be interested to know that in 1822, when he was living in
Pisa, he wrote:
"Who knows whether, when a comet shall approach this globe to destroy
it, as it often has been and will be destroyed, men will not tear rocks
from their foundations by means of steam, and hurl mountains, as the
giants are said to have done, against the flaming mass? And then we
shall have traditions of Titans again, and of wars with Heaven."
An Observing Postscript
Although Comet Encke is only visible every 3.3 years (it returns next
year), we can observe the Taurid meteor stream every year. As mentioned
above, they have a broad display rather than a well-defined peak.
Although their activity spans the period 1st October to 25th November,
there are two separate maxima. The Taurids South maximum lasts for about
a week around 5th November, while the Taurids North maximum similarly
lasts for about a week around 12th November - the two virtually overlap
each other to produce a plateau.
The rates aren't high (at best, about 5 per hour) but they are easily
seen, slow moving, and they have a reputation for producing very bright
fireballs - a fact that has apparently been observed for thousands of
years! The Taurids are visible during this period from late evening
onwards, and with New Moon occurring on Monday 8th November, there will
be no moonlight interference - the shower is well timed for the
Society's monthly star party at Wiruna. Regardless of whether you're at
Wiruna or elsewhere, if the weather is good, why not step outside and
keep an eye on the sky - it will only be a week or two before the
Leonids.
One thing is for certain: debris from the Solar System does hit Earth.
If it didn't, we wouldn't see meteors every night! The astronomical
community (in particular, those who specialise in comets and/or
asteroids) is not yet convinced as a whole about the notion of the inner
Solar System currently suffering from periodic bombardment from the
remains of a fragmented giant comet. Nevertheless, David Morrison,
principal author of NASA's Spaceguard Survey Reports in 1992 and 1995,
and a critic of the British viewpoint, does admit that:
"While I believe that the British neo-catastrophists are wrong about the
threat to Earth, their work is science, not pseudoscience. They are
making their case to other scientists, and time will sort out who is
right and who is wrong."
Regardless of whether the specific theories referred to in this article
turn out to be correct, observing comet debris hitting Earth's
atmosphere now seems to take on a whole new perspective in our
"enlightened ages".
Australia: The Truth is Out There
Everyone in the south-west yesterday had their own big bang theory.
Was it an earthquake? Did Tower Hill erupt into action? Did a meteor shower crash to earth, or was it an alien invasion?
The "big bang" was heard about 1am yesterday, with reports of an "explosion" shaking homes in Winslow, Warrnambool and Terang.
"The whole house shook and there was an almighty noise, like a roar," one Warrnambool resident said yesterday.
"It had my curtains moving and set my car alarm off."
The noise was said to be accompanied by flashes of light that were
variously described as being pink, orange and yellow, and seen as far
away as Mortlake and Heywood.
Perry Vlahos, media liaison for the Astronomical Society of Victoria
(ASV), said it was likely that the bang and the flashes of light were
caused by a meteor.
"It was most likely a meteor exploding in the atmosphere," Mr Vlahos said.
"(The sound) could be a sonic boom or (a meteor) coming through the
atmosphere and exploding. Even though these flashes or sound appear
close, it might be quite a distance above our head."
Don Ward, an ASV member from Gorae West, said the cloudy conditions would have made it difficult to spot a meteor.
"But this talk of lights suggests it might have been an
explosion above the cloud level and it illuminated the clouds," Mr Ward
said.
"(As for the bang), you would get that as the meteor reached a certain
level and the air resistance and friction results in disintegration.
Then if it falls to earth in pieces, that is what we call a meteorite."
Mr Ward said a lack of meteorite pieces or a smoking crater did not
invalidate the theory, as the meteor could have turned to ashes, or they
could have gone into the sea.
The Standard confirmed that it wasn't an earth tremor, with
Geoscience Australia reporting that no seismic activity had been
recorded in the region.
In the absence of a definitive answer - and without any reports of
damage - rumours, pranksters and conspiracy theorists began swirling
early yesterday.
A tsunami was heading towards Lady Bay, an earthquake recording 5.3 on
the Richter Scale caused "extensive minor damage" and a passing defence
force plane had created a sonic boom.
Some seriously questioned if it was alien life or a sign pointing towards a looming apocalypse.
On The Standard's online poll, which had attracted more than
1100 responses last night, more than half thought the "big bang" was
from visiting extraterrestrials.
Scientists find asteroid with potential power of 15 atomic bombs. Heading this way. Tonight.
Fri, 15 Apr 2011 06:56 CDT
News.com.au
© Nasa/JPL
2011 GP59 orbit.
2011 GP59 orbit.
Amateur astronomers across the world have fallen for a cheeky asteroid that passed the Earth on Monday night.
Asteroid 2011 GP59 was caught winking at our planet from a distance away barely 10 times that of the moon.
The "winking" bit which is getting spacefans so hot and bothered stems
from the fact that the asteroid is cigar-shaped and spinning madly
end-to-end, comparatively speaking.
"Usually, when we see an asteroid strobe on and off like that, it means
that the body is elongated and we are viewing it broadside along its
long axis first, and then on its narrow end as it rotates," said Don
Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet
Propulsion Laboratory in Pasadena, California.
"GP59 is approximately 50m long, and we think its period of rotation is about seven-and-a-half minutes.
"This makes the object's brightness change every four minutes or so."
Don't believe Don? Check out Essex star-botherer Nick James's video of 2011 GP59 cruising past some 3,356,000km away.
That's about 10 lunar distances - our moon is 384,400km away - but tomorrow morning, about 5am, things get a little crazy.
For start, Monday's night's discovery of GP 59 was just that - a discovery.
It was picked up by astronomers at the Observatorio Astronomico de
Mallorca in Andalusia, Spain, who've since determined that it's heading
towards us.
Tonight, it will pass just outside the moon's orbit - again,
comparatively speaking because this is space, folks - at a distance of
533,000km.
However, Mr Yeomans, whose office is responsible for a program called
Spaceguard, which tracks and characterises asteroids and comets and is
supposed to protect us from this sort of thing, says there's no need to
be concerned.
"Although newly discovered, the near-term orbital location of asteroid 2011 GP59 can be accurately plotted," he said.
"There is no possibility of the small space rock entering Earth's atmosphere during this pass or for the foreseeable future."
Which is good news, because although 50m might sound smallish, it's
still five times bigger than an asteroid that exploded 15km above
Indonesia in October, 2009.
That blast released as much energy as three atomic bombs, according to New Scientist, who are supposed to know about such things.
Take comfort in the fact that in 2009, no one saw that asteroid coming.
At least we were given three days' notice this time around.
So that's something.
US: Happen to see the April 9th Fireball?
In my time watching the skies, I've seen quite a few meteors,
fireballs, and bolides. The truly notable ones are few and far between,
but last Saturday, I caught one that was among the most interesting I've
seen. It was a slow moving, bright green one with a nice smoke trail
that was easily as bright as Venus from where I saw it in the suburbs of
St. Louis. I tweeted about it briefly but didn't think much more about
it until I got a response from another person that saw it along with a
link to a collection of observations. As nice as the observation was for
me, it was nothing compared to the view some others got.
© Starlight Cascade Observatory
Heading over to the American Meteor Society
page for a meteor around this time, it looks like a meteor matching
the one I saw generated a pretty good number of reports from across the
country. Several have reactions similar to my initial one: This must be a
firework. Many reports confirm the smoke trail and fragmentation as
well. But the reports that are really fantastic are the ones from
Canada.
At the Lunar Meteorite Hunters blog,
several reports have been collected. Several of these reports from
various locations in Ontario report the meteor being as bright as a full
moon and lighting up the entire sky! One even notes that they could
hear a fizzling noise, a rare phenomenon thought to occur when the
passage through the atmosphere creates an ionized path that interacts
with the Earth's magnetic field creating radio waves that could induce
physical vibrations in the air around the observer. Another comment
reports a sonic boom around the same time (although sonic booms would
occur well after the meteor was visible due to the sluggish nature of
sound waves, much like the delay between lightning and thunder).
It doesn't look like NASA's All Sky Fireball Network caught this fireball, but an amateur observatory equipped with an all sky camera for detecting fireballs did catch the event.
The green color for such meteors is uncommon but not unprecedented. The
presence of magnesium ions is responsible for this color. Interestingly,
another famous meteor, the Peekskill meteor,
also had a green color and rivaled the full moon in brightness. This
meteor became famous because it was independently captured in at least
sixteen videos (here's one showing the green tint) as well as for surviving intact to the ground and damaging a car.
Meteors of this intensity are quite rare but bright fireballs like this
seem to peak around the vernal equinox. In the weeks surrounding that
day, the rate of such events increases around 10-30%.
Astronomers Study Unusual Asteroid
© NASA/JPL-Caltech/UCLA/PSI
This
image shows a model of the protoplanet Vesta, using scientists' best
guess to date of what the surface of the protoplanet might look like. It
was created as part of an exercise for NASA's Dawn mission
involving mission planners at NASA's Jet Propulsion Laboratory and
science team members at the Planetary Science Institute in Tuscon,
Arizona
This
image shows a model of the protoplanet Vesta, using scientists' best
guess to date of what the surface of the protoplanet might look like. It
was created as part of an exercise for NASA's Dawn mission
involving mission planners at NASA's Jet Propulsion Laboratory and
science team members at the Planetary Science Institute in Tuscon,
Arizona
You've heard of Pluto, once a full-scale
planet that astronomers now classify as a dwarf planet. Now meet 4 Vesta
-- or Vesta for short -- an asteroid that may not be a real asteroid.
The 330-mile diameter object sits in the asteroid belt, a collection of
large and small pieces of rubble that circles the sun between the orbits
of the planets Mars and Jupiter. But Vesta, numbered 4 because it was
the fourth member of the asteroid belt to be discovered, is larger than
most of its asteroid companions and also differs from them geologically.
An unmanned NASA spacecraft called Dawn is now heading for Vesta to explore those differences.
"There are at least two classes of objects that have been called
asteroids," said Thomas McCord, director of the Bear Fight Institute in
Winthrop, Washington. "The real asteroids are broken up pieces of rock
100 kilometers (62 miles) in diameter or smaller. The others are more like small planets."
In addition to Vesta those others include Ceres, the largest asteroid
and first to be discovered, and Pallas, the second asteroid to be
spotted. Ceres is now classified as a dwarf planet like Pluto.
However, Vesta is unique in several respects. It is denser than Ceres and Pallas. It also appears to be differentiated into a rocky surface and an iron core,
like the terrestrial planets Earth, Mars, and Venus. And it is
continually shedding material from its surface as a result of collisions
with small asteroids.
"There are little pieces of Vesta all over the asteroid belt," said Tim
Spahr, director of the Minor Planet Center at the Harvard-Smithsonian
Center for Astrophysics in Cambridge, Massachusetts.
Astronomers have already had a close-up view of some of those pieces
because some of them have landed on the Earth's surface as meteorites.
Scientists recognized their provenance by studying their spectra, which
indicates their chemical composition, and comparing them with Vesta's
spectrum.
Ceres and Pallas, which differ from Vesta geologically, shed less
debris. "Whatever they are made of doesn't travel well," said
Christopher Russell, professor of geology at the University of
California, Los Angeles.
Telescope observations by McCord in 1972 revealed that Vesta's surface
consists of a rock called basalt, which on Earth is made from cooled
magma.
"The basalt would make it unique in that category of objects," Spahr said.
"We think of it as a very large asteroid that is very Earthlike -- called Vesta, the smallest terrestrial planet," Russell said.
Astronomers believe that Earth and similar planets formed when a series
of small bodies coalesced. "We think that these bodies were around in
large numbers and came together to build planets," Russell explained.
McCord added that the problem with Vesta is that "it didn't find a
companion to become a piece of a bigger object that would coalesce with
other companions." So it remained by itself, a kind of time capsule from
an early era in our solar system.
Russell oversees the Dawn mission with McCord as a co-investigator. Dawn
is scheduled to reach Vesta in July and spend a year in orbit, using an
infrared spectrometer, a camera, and a gamma ray detector to explore
Vesta's composition.
The team expects to determine whether basalt uniformly covers Vesta's
surface and where on the surface meteorites originate. The mission will
also probe a large crater in Vesta's southern hemisphere that has
exposed its interior.
"If it is really differentiated, we would see minerals at depths similar to what we see in the Earth's mantle," McCord said.
When it leaves Vesta, the Dawn mission will travel to Ceres, which is larger, rounder, and wetter than Vesta.
By studying the contrasts between the two objects, astronomers hope to
obtain clues to the ways in which the terrestrial planets evolved.
"We're going to try to understand what the building blocks of the early
solar system were like," Russell said. "It's really about tracing our
family tree and understanding where we come from."
Will the findings lead astronomers to reclassify Vesta? Probably not. At
the same 2006 meeting where Pluto was demoted to minor planet status, Vesta was designated one of 269,644 minor planets.
"It was given minor planet number 4, and nobody has worried about [its classification] since," Spahr said.
Comment: Could these protoplanet asteroids be
formed under electrical heating conditions described by James McCanney's
Comet Capture Theory of Solar System formation? For further reading
see:
Planet-X, Comets and Earth Changes by J.M. McCanney
'Impact: Earth!' Asteroid, Comet and Damage Simulation Website
Sat, 16 Apr 2011 11:37 CDT
Gather.com
© Purdue University
Purdue
University has created "Impact: Earth!," a website where anyone can see
the simulated effects when a comet or asteroid of variable size,
density, and speed hits Earth. Many people believe that asteroid and
comet impacts have played a major role in the history of Earth, and
Purdue has provided us with an inside look at how previous impacts might affect us today.
The Interactive website is said to be scientifically accurate enough to
be used by many different branches of the government including NASA and
the Department of Homeland Security.
Comment: Now we feel much more "reassured" to know
that NASA and the Department of Homeland Security are using the
simulation, and yet don't give the topic its deserved urgent attention.
Unless, of course, they are using the program to calculate the best
location for their private underground bunkers.
It is also user-friendly and visual enough
to be used by schools as an interactive teaching aid for elementary
students. This adds a possible new and exciting way for kids to be
physically hands on and learn about the earth and how impacts might
affect us.
The "Impact: Earth!" simulation and report
were written by Gareth Collins, H. Jay Melosh and Robert Marcus, all
experts in various fields. They go on to say "There have been big
impacts in the past, and we expect big impacts in the future. This site
gives the lowdown on what happens when such an impact occurs." The team
has also answered requests and factored in Tsunamis brought on by
impacting comets or asteroids. There are also plans in the works to
connect the program with Google Earth to show a map of the effects.
Singapore - Rare Sight: 'Fireball' Streaks Across Evening Sky
Mon, 18 Apr 2011 02:01 CDT
Stomp
© STOMP
Two STOMPers caught sight of what seemed to be a meteor streaking across the sky last evening (Apr 17).
JJ123, one of the STOMPers who saw the meteor, said:
"My friend and I were on our way to dinner when we chanced upon something unusual in the sky.
"Initially, we tried to convince ourselves that it was an aeroplane
flying across the sky. After much observation, we realised that it
seemed more likely to be a meteor falling from the sky.
"It was definitely a rare sight in the heartlands. Photographs of the
incident were captured in Chong Pang, right in front of the Nee Soon
Camp in the evening."
Another STOMPer Diyar, who also spotted the meteor, said:
"I saw a flame-like object in the sky. It was moving, and I had to run
into a clearing to get a shot of it on my silly iPhone cam.
"And when I tried to get a second shot, it disappeared.
"It would be nice if it were Superman's pod."
More Images
US: New Mexico Fireball
© Heliotown
Still from the video.
Fireball of 10 April 2011 Over Northern Italy
A fireball of zenithal magnitude -13.4 was captured over N Italy on
April 10, 2011 at 02h31m UT (00h31m LT). The bright object, ended with a
big explosion, was taken by E.Stomeo from the automatic meteor station
(IMO # 14083) of UAI-Meteor Section network, operating near Venice with
ccd cameras and all-sky fisheye lens.
Asteroid or Planet? NASA Aims to Settle Vesta Debate
SPACE.com
Scientists still aren't sure what to make of Vesta, a small body that orbits the sun. Is it an asteroid or a planet?
NASA's Dawn spacecraft could settle the matter.
Vesta was spotted 200 years ago and is officially a "minor planet" - a
body that orbits the sun but is not a proper planet or comet. Yet, many astronomers call Vesta an asteroid because it lies in the main asteroid belt between Mars and Jupiter.
But Vesta is not a typical member of that orbiting rubble
patch. The vast majority of objects in the main belt are relative
lightweights, 62 miles(100 kilometers) wide or smaller, compared with
Vesta, which is 329 miles(530 km) wide.
If Vesta is an asteroid, it would be the second-largest in the solar
system. Some scientists, however, are skeptical about that designation. [5 Reasons to Care About Asteroids]
"I don't think Vesta should be called an asteroid," said Tom McCord, a
Dawn team member at the Bear Fight Institute in Winthrop, Wash. "Not
only is Vesta so much larger, but it's an evolved object, unlike most
things we call asteroids."
The evolution of Vesta
The onion-like structure of Vesta (core, mantle and crust) is the key
trait that makes Vesta more like planets such as Earth, Venus and Mars
than the other asteroids, McCord said.
Like the planets, Vesta had sufficient radioactive material inside when
it formed, releasing heat that melted rock and enabled lighter layers to
float to the outside. Signatures of a type of volcanic rock called
basalt were detected in 1972, which meant that the body had to have
melted at one time.
Bu calling Vesta a 'minor planet' is not distinctive enough, since there
are more than 540,000 minor planets in our solar system. Dwarf planets
- which include Ceres, the second destination of NASA's Dawn mission -
are another category, but Vesta doesn't qualify as one of those. For
one thing, Vesta isn't quite large enough to be considered a dwarf
planet.
Dawn scientists prefer to think of Vesta as a protoplanet because it is a
dense, layered body that orbits the sun and formed in the same fashion
as Mercury, Venus, Earth and Mars, but somehow never fully developed.
Early planet formation
In the early history of the solar system, objects became planets by
merging with other objects the size of Vesta. But Vesta never found a
partner during the big dance, and the critical time passed. It may have
had to do with the nearby presence of Jupiter, the gravitational
superpower in the neighborhood, disturbing the orbits of nearby objects
and hogging the dance partners.
Still, Vesta saw its fair share of action.
Other space rocks have collided
with Vesta and knocked off bits of it. This debris in the asteroid belt
became known as Vestoids, and hundreds of these types of meteorites
have ended up on Earth.
Vesta never collided with an object of sufficient size to disrupt it,
however, which is why it has remained intact. As a result, Vesta is like
a time capsule from that earlier era.
"This gritty little protoplanet has survived bombardment in the asteroid
belt for over 4.5 billion years, making its surface possibly the oldest
planetary surface in the solar system," said Christopher Russell, a
Dawn team member, based at UCLA. "Studying Vesta will enable us to write
a much better history of the solar system's turbulent youth."
Dawn's game plan
Dawn's scientists and engineers have designed a master plan to investigate Vesta's special features.
When Dawn arrives
at Vesta in July, the south pole will be in full sunlight, giving
scientists a clear view of a huge crater there. The crater may reveal
the layer cake of materials inside Vesta, which could help scientists
understand how the body evolved after its formation.
The way scientists have designed Dawn's orbit will also allow the
spacecraft to map new terrain as the seasons progress during its
12-month visit.
The spacecraft will take many measurements, including high-resolution
data of Vesta's surface composition, topography and texture. Dawn will
also measure the tug of Vesta's gravity to learn more about its internal
structure.
"Dawn's ion thrusters are gently carrying us toward Vesta, and the
spacecraft is getting ready for its big year of exploration," said Marc
Rayman, Dawn's chief engineer at NASA's Jet Propulsion Laboratory in
Pasadena, Calif. "We have designed our mission to get the most out of
this opportunity to reveal the exciting secrets of this uncharted,
exotic world."
Panspermia - A Distinct Posibility? Alien Bacteria Could Breed in Extreme 'Hypergravity'
If alien life is out there, it may be able to exploit more-extreme
environments than scientists think, because huge gravitational forces
don't seem to pose much of a problem for microbes.
Several different species of bacteria can survive and reproduce in
"hypergravity" more than 400,000 times stronger than that of the Earth, a
new study reports. The find suggests that alien life
could take root in a wide range of conditions -- and that it could
survive the high G-forces imposed by meteorite impacts and ejections, making the exchange of life between planets a distinct possibility.
"The number and types of environments that we now think life can inhabit
in the universe has expanded because of our study," said lead author
Shigeru Deguchi, of the Japan Agency of Marine-Earth Science and
Technology in Yokosuka. [5 Bold Claims of Alien Life]
A fortuitous find
Deguchi and his colleagues didn't set out to establish the high
gravitational tolerances of microbes. Rather, they simply wanted to
measure the density of Escherichia coli bacteria cells, using a centrifuge.
When they spun E. coli up to the equivalent of 7,500
G's (7,500 times the force of Earth gravity), however, they found that
the microbe didn't miss a beat. It grew and reproduced just fine.
"The finding was a total surprise to us, and stimulated our curiosity
very much," Deguchi told SPACE.com in an email interview."So we repeated
[the] same experiments at higher G, and eventually found that E. coli proliferates even at 400,000 G, which was the highest gravity we could achieve by our instrument."
By contrast, anything above about 50 G's invites serious injury or death
in humans, even if the exposure is for just a few hundredths of a
second. Astronauts aboard NASA's space shuttle experience up to around 3
G's on liftoff and re-entry.
The researchers expanded their experiment, exposing four other microbe
species to hypergravity for up to 140 hours. They found that another
bacterium, Paracoccus denitrificans, can also reproduce at about 400,000 G's, though its proliferation -- like that of E. coli -- is stunted in such extreme conditions.
P. denitrificans and E. coli were the hypergravity-tolerance champs, but all five examined species could reproduce to some extent up to about 20,000 G's.
Deguchi and his colleagues report their results today (April 25) in the journal Proceedings of the National Academy of Sciences (PNAS).
A wide range of habitats?
While previous studies had demonstrated that some microorganisms
can survive gravity exceeding 15,000 G's, the new research breaks
ground by showing that a variety of microbes can actually proliferate in
hypergravity.
The only comparable study the researchers are aware of found that E. coli
can grow at 100,000 G's. Deguchi says that paper, published in 1963,
didn't attract much notice because it was ahead of its time.
"The paper was published two years before microorganisms thriving
extreme conditions were widely recognized by the discovery of
thermophilic microorganisms in Yellowstone National Park in 1965,"
Deguchi said. [Extremophiles: The World's Weirdest Life]
The new study suggests that a wider variety of alien habitats may be open to life than scientists had imagined. The
results even extend the possibility of life beyond planets, to the
strange "failed stars" known as brown dwarfs, researchers said.
After all, if Earth bacteria can breed in 400,000 G's, the 10-to-100 G's
possibly found on a brown dwarf shouldn't be much of an impediment. And
some brown dwarfs may be cool enough to support life as we know it,
researchers said.
Panspermia possible?
The results also suggest that the transport of viable lifeforms between worlds is a real possibility, researchers said.
Over the ages, Earth has been showered with perhaps 1 billion tons of Mars rocks,
which were liberated from the Red Planet via meteorite strikes. Such
interplanetary exchanges, in our solar system or others, could
theoretically transfer microbes as well -- an aspect of the "panspermia"
hypothesis, which posits that the seeds of life are everywhere and
hopscotch from world to world.
Scientists think meteorite-caused rock ejections can generate up to
300,000 G's, researchers said. The new study indicates that microbial
life could survive those conditions and keep right on breeding.
"If life does exist in other places in the universe, our study
provides further evidence that it could spread within solar systems by
the mechanism often discussed in panspermia hypotheses -- i.e.,
impact-based transport of meteorites between bodies of the same solar
system," Deguchi said.
Comment: The possibility of lifeforms being
transported across the Universe is certainly an intriguing one,
especially when we consider that our roots as species may lie somewhere
outside this planet.
From The Golden Age, Psychopathy and the Sixth Extinction by Laura Knight-Jadczyk:
Cosmic collision: Nasa monitors unusually bright asteroid after 11,000mph impact
The Daily Mail
An unexpectedly bright asteroid that sported short-lived plumes had collided with a smaller body, scientists have said.
The aftermath of the impact on Scheila was first spotted by the
University of Arrizona's Catalina Sky Survey on December 11 last year.
It revealed Scheila to be twice as bright as expected and immersed in a faint comet-like glow.
Looking through the survey's archived images, astronomers inferred the outburst began between November 11 and December 3.
Data from Nasa's Swift satellite and Hubble Space Telescope then showed these changes likely occurred after Scheila was struck by a much smaller asteroid.
'Collisions between asteroids create rock fragments, from fine dust to
huge boulders, that impact planets and their moons,' said lead Swift
researcher Dennis Bodewits, from the University of Maryland.
'Yet this is the first time we've been able to catch one just weeks after the smash-up, long before the evidence fades away.'
Asteroids are rocky fragments thought to be debris from the formation
and evolution of the solar system approximately 4.6billion years ago.
Millions of them orbit the sun between Mars and Jupiter in the
main asteroid belt. Scheila is approximately 70 miles across and orbits
the sun every five years.
Hubble observed the asteroid's fading dust cloud on December 27 and January 4.
'The Hubble data is most simply explained by the impact, at 11,000 mph,
of a previously unknown asteroid about 100ft in diameter,' said Hubble
team leader David Jewitt of the University of California in Los Angeles.
Hubble did not see any discrete collision fragments, unlike its 2009
observations of P/2010 A2, the first identified asteroid collision.
Astronomers have known for decades that comets contain icy material that
erupts when warmed by the sun. They regarded asteroids as inactive
rocks whose destinies, surfaces, shapes and sizes were determined by
mutual impacts.
However, this simple picture has grown more complex over the past few years.
During
certain parts of their orbits, some objects, once categorised as
asteroids, clearly develop comet-like features that can last for many
months.
Others display much shorter outbursts. Icy materials may be occasionally
exposed, either by internal geological processes or by an external one,
such as an impact.
Three days after the outburst was announced, Swift's Ultraviolet/Optical
Telescope (UVOT) captured multiple images and a spectrum of the
asteroid.
Ultraviolet sunlight breaks up the gas molecules surrounding comets -
water, for example, is transformed into hydroxyl and hydrogen.
But none of the emissions most commonly identified in comets, such as hydroxyl or cyanogen, show up in the UVOT spectrum.
The absence of gas around Scheila led the Swift team to reject scenarios where exposed ice accounted for the activity.
Images show the asteroid was flanked in the north by a bright dust plume
and in the south by a fainter one. The dual plumes formed as small dust
particles excavated by the impact were pushed away from the asteroid by
sunlight.
The two teams found the observations were best explained by a collision
with a small asteroid impacting Scheila's surface at an angle of less
than 30 degrees, leaving a crater 1,000ft across.
Laboratory experiments show a more direct strike probably wouldn't have produced two distinct dust plumes.
The researchers estimated the crash ejected more than 660,000 tons of
dust - equivalent to nearly twice the mass of the Empire State Building.
Study co-author Michael Kelley, also of the University of Maryland,
said: 'The dust cloud around Scheila could be 10,000 times as massive as
the one ejected from comet 9P/Tempel 1 during Nasa's UMD-led Deep
Impact mission.
'Collisions allow us to peek inside comets and asteroids. Ejecta kicked
up by Deep Impact contained lots of ice, and the absence of ice in
Scheila's interior shows that it's entirely unlike comets.
The research will appear in The Astrophysical Journal Letters.
Comment: The article says: "Ejecta kicked up by
Deep Impact contained lots of ice, and the absence of ice in Scheila's
interior shows that it's entirely unlike comets." But perhaps it isn't
entirely true, and comets are not the "dirty snowballs" we are led to
believe by NASA scientists. Read Planet-X, Comets and Earth Changes by J.M. McCanney to learn more.
Still from the video.
Fireball of 10 April 2011 Over Northern Italy
A fireball of zenithal magnitude -13.4 was captured over N Italy on
April 10, 2011 at 02h31m UT (00h31m LT). The bright object, ended with a
big explosion, was taken by E.Stomeo from the automatic meteor station
(IMO # 14083) of UAI-Meteor Section network, operating near Venice with
ccd cameras and all-sky fisheye lens.
Asteroid or Planet? NASA Aims to Settle Vesta Debate
Fri, 22 Apr 2011 13:20 CDT
SPACE.com
Scientists still aren't sure what to make of Vesta, a small body that orbits the sun. Is it an asteroid or a planet?
NASA's Dawn spacecraft could settle the matter.
Vesta was spotted 200 years ago and is officially a "minor planet" - a
body that orbits the sun but is not a proper planet or comet. Yet, many astronomers call Vesta an asteroid because it lies in the main asteroid belt between Mars and Jupiter.
© Ben Zellner (Georgia Southern University) / Peter Thomas (Cornell University) / NASA
On
its southern side the asteroid Vesta shows a huge crater. This picture
shows the asteroid in an image taken by the Hubble Space Telescope (top,
left), as a reconstruction based on theoretical calculations (top,
right), and as a topological map (bottom).
On
its southern side the asteroid Vesta shows a huge crater. This picture
shows the asteroid in an image taken by the Hubble Space Telescope (top,
left), as a reconstruction based on theoretical calculations (top,
right), and as a topological map (bottom).
But Vesta is not a typical member of that orbiting rubble
patch. The vast majority of objects in the main belt are relative
lightweights, 62 miles(100 kilometers) wide or smaller, compared with
Vesta, which is 329 miles(530 km) wide.
If Vesta is an asteroid, it would be the second-largest in the solar
system. Some scientists, however, are skeptical about that designation. [5 Reasons to Care About Asteroids]
"I don't think Vesta should be called an asteroid," said Tom McCord, a
Dawn team member at the Bear Fight Institute in Winthrop, Wash. "Not
only is Vesta so much larger, but it's an evolved object, unlike most
things we call asteroids."
The evolution of Vesta
The onion-like structure of Vesta (core, mantle and crust) is the key
trait that makes Vesta more like planets such as Earth, Venus and Mars
than the other asteroids, McCord said.
Like the planets, Vesta had sufficient radioactive material inside when
it formed, releasing heat that melted rock and enabled lighter layers to
float to the outside. Signatures of a type of volcanic rock called
basalt were detected in 1972, which meant that the body had to have
melted at one time.
Bu calling Vesta a 'minor planet' is not distinctive enough, since there
are more than 540,000 minor planets in our solar system. Dwarf planets
- which include Ceres, the second destination of NASA's Dawn mission -
are another category, but Vesta doesn't qualify as one of those. For
one thing, Vesta isn't quite large enough to be considered a dwarf
planet.
Dawn scientists prefer to think of Vesta as a protoplanet because it is a
dense, layered body that orbits the sun and formed in the same fashion
as Mercury, Venus, Earth and Mars, but somehow never fully developed.
Early planet formation
In the early history of the solar system, objects became planets by
merging with other objects the size of Vesta. But Vesta never found a
partner during the big dance, and the critical time passed. It may have
had to do with the nearby presence of Jupiter, the gravitational
superpower in the neighborhood, disturbing the orbits of nearby objects
and hogging the dance partners.
Still, Vesta saw its fair share of action.
Other space rocks have collided
with Vesta and knocked off bits of it. This debris in the asteroid belt
became known as Vestoids, and hundreds of these types of meteorites
have ended up on Earth.
Vesta never collided with an object of sufficient size to disrupt it,
however, which is why it has remained intact. As a result, Vesta is like
a time capsule from that earlier era.
"This gritty little protoplanet has survived bombardment in the asteroid
belt for over 4.5 billion years, making its surface possibly the oldest
planetary surface in the solar system," said Christopher Russell, a
Dawn team member, based at UCLA. "Studying Vesta will enable us to write
a much better history of the solar system's turbulent youth."
Dawn's game plan
Dawn's scientists and engineers have designed a master plan to investigate Vesta's special features.
When Dawn arrives
at Vesta in July, the south pole will be in full sunlight, giving
scientists a clear view of a huge crater there. The crater may reveal
the layer cake of materials inside Vesta, which could help scientists
understand how the body evolved after its formation.
The way scientists have designed Dawn's orbit will also allow the
spacecraft to map new terrain as the seasons progress during its
12-month visit.
The spacecraft will take many measurements, including high-resolution
data of Vesta's surface composition, topography and texture. Dawn will
also measure the tug of Vesta's gravity to learn more about its internal
structure.
"Dawn's ion thrusters are gently carrying us toward Vesta, and the
spacecraft is getting ready for its big year of exploration," said Marc
Rayman, Dawn's chief engineer at NASA's Jet Propulsion Laboratory in
Pasadena, Calif. "We have designed our mission to get the most out of
this opportunity to reveal the exciting secrets of this uncharted,
exotic world."
Panspermia - A Distinct Posibility? Alien Bacteria Could Breed in Extreme 'Hypergravity'
If alien life is out there, it may be able to exploit more-extreme
environments than scientists think, because huge gravitational forces
don't seem to pose much of a problem for microbes.
Several different species of bacteria can survive and reproduce in
"hypergravity" more than 400,000 times stronger than that of the Earth, a
new study reports. The find suggests that alien life
could take root in a wide range of conditions -- and that it could
survive the high G-forces imposed by meteorite impacts and ejections, making the exchange of life between planets a distinct possibility.
"The number and types of environments that we now think life can inhabit
in the universe has expanded because of our study," said lead author
Shigeru Deguchi, of the Japan Agency of Marine-Earth Science and
Technology in Yokosuka. [5 Bold Claims of Alien Life]
© CDC/Janice Haney Carr
Colorized
scanning electron micrograph depicting Escherichia coli bacteria, which
recent research shows can breed in gravity 400,000 times stronger than
that of Earth. Most E. coli strains are harmless, but the one here is
O157:H7, which can cause severe illness in people.
Colorized
scanning electron micrograph depicting Escherichia coli bacteria, which
recent research shows can breed in gravity 400,000 times stronger than
that of Earth. Most E. coli strains are harmless, but the one here is
O157:H7, which can cause severe illness in people.
A fortuitous find
Deguchi and his colleagues didn't set out to establish the high
gravitational tolerances of microbes. Rather, they simply wanted to
measure the density of Escherichia coli bacteria cells, using a centrifuge.
When they spun E. coli up to the equivalent of 7,500
G's (7,500 times the force of Earth gravity), however, they found that
the microbe didn't miss a beat. It grew and reproduced just fine.
"The finding was a total surprise to us, and stimulated our curiosity
very much," Deguchi told SPACE.com in an email interview."So we repeated
[the] same experiments at higher G, and eventually found that E. coli proliferates even at 400,000 G, which was the highest gravity we could achieve by our instrument."
By contrast, anything above about 50 G's invites serious injury or death
in humans, even if the exposure is for just a few hundredths of a
second. Astronauts aboard NASA's space shuttle experience up to around 3
G's on liftoff and re-entry.
The researchers expanded their experiment, exposing four other microbe
species to hypergravity for up to 140 hours. They found that another
bacterium, Paracoccus denitrificans, can also reproduce at about 400,000 G's, though its proliferation -- like that of E. coli -- is stunted in such extreme conditions.
P. denitrificans and E. coli were the hypergravity-tolerance champs, but all five examined species could reproduce to some extent up to about 20,000 G's.
Deguchi and his colleagues report their results today (April 25) in the journal Proceedings of the National Academy of Sciences (PNAS).
A wide range of habitats?
While previous studies had demonstrated that some microorganisms
can survive gravity exceeding 15,000 G's, the new research breaks
ground by showing that a variety of microbes can actually proliferate in
hypergravity.
The only comparable study the researchers are aware of found that E. coli
can grow at 100,000 G's. Deguchi says that paper, published in 1963,
didn't attract much notice because it was ahead of its time.
"The paper was published two years before microorganisms thriving
extreme conditions were widely recognized by the discovery of
thermophilic microorganisms in Yellowstone National Park in 1965,"
Deguchi said. [Extremophiles: The World's Weirdest Life]
The new study suggests that a wider variety of alien habitats may be open to life than scientists had imagined. The
results even extend the possibility of life beyond planets, to the
strange "failed stars" known as brown dwarfs, researchers said.
After all, if Earth bacteria can breed in 400,000 G's, the 10-to-100 G's
possibly found on a brown dwarf shouldn't be much of an impediment. And
some brown dwarfs may be cool enough to support life as we know it,
researchers said.
Panspermia possible?
The results also suggest that the transport of viable lifeforms between worlds is a real possibility, researchers said.
Over the ages, Earth has been showered with perhaps 1 billion tons of Mars rocks,
which were liberated from the Red Planet via meteorite strikes. Such
interplanetary exchanges, in our solar system or others, could
theoretically transfer microbes as well -- an aspect of the "panspermia"
hypothesis, which posits that the seeds of life are everywhere and
hopscotch from world to world.
Scientists think meteorite-caused rock ejections can generate up to
300,000 G's, researchers said. The new study indicates that microbial
life could survive those conditions and keep right on breeding.
"If life does exist in other places in the universe, our study
provides further evidence that it could spread within solar systems by
the mechanism often discussed in panspermia hypotheses -- i.e.,
impact-based transport of meteorites between bodies of the same solar
system," Deguchi said.
Comment: The possibility of lifeforms being
transported across the Universe is certainly an intriguing one,
especially when we consider that our roots as species may lie somewhere
outside this planet.
From The Golden Age, Psychopathy and the Sixth Extinction by Laura Knight-Jadczyk:
We note that the Spedicato paper cited above proposes that the last
glaciation began with a cometary collision or explosion over land.
Perhaps we find here a clue to the sudden appearance of Cro-Magnon man?
I have here on my desk a paper by Rhawn Joseph and Chandra Wickramasinghe entitled Comets and Contagion: Evolution and Diseases From Space. They write in their conclusions:
"Correlation is not causation and thus no firm conclusions can be drawn
despite the wealth of evidence suggesting a link between comets and
diseases from space. Nevertheless, comets are an ideal vehicle for
sustaining and transporting a variety of microbes, including viruses,
from planet to planet and even from solar system to solar system. In
consequence, when these organisms are deposited on a world already
thriving with life, genes may be exchanged, the evolution of new species
may ensue, or conversely contagion may be unleashed, and disease,
death, and plague may spread throughout the land."
Let us speculate that the genes that produced Cro-Magnon man may have
been brought to earth as the result of a cometary impact. The simplest
version of this panspermia theory is that proposed by Sir Fred Hoyle and
Chandra Wickramasinghe who suggest that life forms continue to enter
the earth's atmosphere, and may be responsible for epidemic outbreaks,
new diseases, and the genetic novelty necessary for macroevolution. The
mechanisms proposed for interstellar panspermia may include radiation
pressure and lithopanspermia (microorganisms in rocks), deliberate
directed panspermia from space to seed Earth. Interplanetary transfer of
material is well documented, as evidenced by meteorites of Martian
origin found on Earth. [...]
Now, 'panspermia', as the
DNA-transported-by-comets-seeding-life-on-earth theory is called, may
get us off the hook as far as human evolution on earth is concerned, but
it does not get us off the hook when considering where that DNA came
from originally and how the individuals who carried it evolved, if the
arguments against evolution that the panspermia scientists employ apply
everywhere. Obviously, they are under the same constraints. On the other
hand, that may be a way out in a different direction: DNA could be a
pure manifestation of consciousness, a sort of first-level physicality,
the interface between the material and non-material worlds. Pure
information might be able to geometrize itself in the form of DNA and,
voilà! the building blocks of life that are complex and capable of
inducting consciousness itself into matter come into being in an
instant. Sort of a mini-Big Bang with consciousness present to guide the
'explosion'.
Cosmic collision: Nasa monitors unusually bright asteroid after 11,000mph impact
Fri, 29 Apr 2011 23:11 CDT
The Daily Mail
An unexpectedly bright asteroid that sported short-lived plumes had collided with a smaller body, scientists have said.
The aftermath of the impact on Scheila was first spotted by the
University of Arrizona's Catalina Sky Survey on December 11 last year.
It revealed Scheila to be twice as bright as expected and immersed in a faint comet-like glow.
© NASA
Collision:
Faint dust plumes bookend asteroid Scheila in this composite taken by
Nasa's Swift satellite on December 15 last year when it was 232million
miles from Earth
Collision:
Faint dust plumes bookend asteroid Scheila in this composite taken by
Nasa's Swift satellite on December 15 last year when it was 232million
miles from Earth
Looking through the survey's archived images, astronomers inferred the outburst began between November 11 and December 3.
Data from Nasa's Swift satellite and Hubble Space Telescope then showed these changes likely occurred after Scheila was struck by a much smaller asteroid.
'Collisions between asteroids create rock fragments, from fine dust to
huge boulders, that impact planets and their moons,' said lead Swift
researcher Dennis Bodewits, from the University of Maryland.
'Yet this is the first time we've been able to catch one just weeks after the smash-up, long before the evidence fades away.'
Asteroids are rocky fragments thought to be debris from the formation
and evolution of the solar system approximately 4.6billion years ago.
Millions of them orbit the sun between Mars and Jupiter in the
main asteroid belt. Scheila is approximately 70 miles across and orbits
the sun every five years.
Hubble observed the asteroid's fading dust cloud on December 27 and January 4.
'The Hubble data is most simply explained by the impact, at 11,000 mph,
of a previously unknown asteroid about 100ft in diameter,' said Hubble
team leader David Jewitt of the University of California in Los Angeles.
Hubble did not see any discrete collision fragments, unlike its 2009
observations of P/2010 A2, the first identified asteroid collision.
Astronomers have known for decades that comets contain icy material that
erupts when warmed by the sun. They regarded asteroids as inactive
rocks whose destinies, surfaces, shapes and sizes were determined by
mutual impacts.
However, this simple picture has grown more complex over the past few years.
© NASA
This
Hubble Space Telescope image was taken on December 27, when the
asteroid was 218million miles away. Scheila is surrounded by a C-shaped
cloud of particles and displays a linear dust tail
This
Hubble Space Telescope image was taken on December 27, when the
asteroid was 218million miles away. Scheila is surrounded by a C-shaped
cloud of particles and displays a linear dust tail
During
certain parts of their orbits, some objects, once categorised as
asteroids, clearly develop comet-like features that can last for many
months.
Others display much shorter outbursts. Icy materials may be occasionally
exposed, either by internal geological processes or by an external one,
such as an impact.
Three days after the outburst was announced, Swift's Ultraviolet/Optical
Telescope (UVOT) captured multiple images and a spectrum of the
asteroid.
Ultraviolet sunlight breaks up the gas molecules surrounding comets -
water, for example, is transformed into hydroxyl and hydrogen.
But none of the emissions most commonly identified in comets, such as hydroxyl or cyanogen, show up in the UVOT spectrum.
The absence of gas around Scheila led the Swift team to reject scenarios where exposed ice accounted for the activity.
Images show the asteroid was flanked in the north by a bright dust plume
and in the south by a fainter one. The dual plumes formed as small dust
particles excavated by the impact were pushed away from the asteroid by
sunlight.
The two teams found the observations were best explained by a collision
with a small asteroid impacting Scheila's surface at an angle of less
than 30 degrees, leaving a crater 1,000ft across.
Laboratory experiments show a more direct strike probably wouldn't have produced two distinct dust plumes.
The researchers estimated the crash ejected more than 660,000 tons of
dust - equivalent to nearly twice the mass of the Empire State Building.
Study co-author Michael Kelley, also of the University of Maryland,
said: 'The dust cloud around Scheila could be 10,000 times as massive as
the one ejected from comet 9P/Tempel 1 during Nasa's UMD-led Deep
Impact mission.
'Collisions allow us to peek inside comets and asteroids. Ejecta kicked
up by Deep Impact contained lots of ice, and the absence of ice in
Scheila's interior shows that it's entirely unlike comets.
The research will appear in The Astrophysical Journal Letters.
Comment: The article says: "Ejecta kicked up by
Deep Impact contained lots of ice, and the absence of ice in Scheila's
interior shows that it's entirely unlike comets." But perhaps it isn't
entirely true, and comets are not the "dirty snowballs" we are led to
believe by NASA scientists. Read Planet-X, Comets and Earth Changes by J.M. McCanney to learn more.
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