05 October 2008

October 2008



Meteorites From Inner Solar System Match Up To Earth's Platinum Standard



Science Daily

Sat, 04 Oct 2008 03:52 UTC


Some of the world's rarest and most precious metals, including platinum
and iridium, could owe their presence in the Earth's crust to iron and
stony-iron meteorites, fragments of a large number of asteroids that
underwent significant geological processing in the early Solar System.


asteroid impact with early Earth
© ESA

Artist's impression of asteroid impact with early Earth that led to lunar formation.




Dr Gerhard Schmidt from the University of Mainz, Germany, has
calculated that about 160 metallic asteroids of about 20 kilometres in
diameter would be sufficient to provide the concentrations of these
metals, known as Highly Siderophile Elements (HSE), found in the
Earth's crust. Dr Schmidt will be presenting his findings at the
European Planetary Science Congress in M√ľnster on Monday 22nd
September.




Dr Schmidt said, "A key issue for understanding the origin of
planets is the knowledge of the abundances of HSE in the crust and
mantle of the Earth, Mars and the Moon. We have found remarkably
uniform abundance distributions of HSE in our samples of the Earth's
upper crust. A comparison of these HSE values with meteorites strongly
suggests that they have a cosmochemical source."



During a 12-year study, Dr Schmidt and colleagues have
analysed the concentrations of HSE at meteorite impact sites around the
world, as well as in the samples from the Earth's mantle and crust. In
addition, he has compared the data from the Earth with data from impact
breccias from the Moon brought by the Apollo missions and Martian
meteorites, believed to be samples from the mantle and crust on Mars.




Although HSE were present in the nebula from which the Earth
formed, as the young planet evolved and heated up they were stripped,
along with other heavy elements, from the silicate mantle into the iron
and nickel-rich metallic core. The presence of HSE in the mantle is
still a matter of debate. However, a widely accepted theory is that HSE
were added by meteorite impacts as a veneer of material over the
Earth's surface after the core had formed, about 20-30 million years
after the planet's accretion. This could have been by the collision
with a Mars-sized impactor that led to the formation of the Moon.




Different classes of meteorites have characteristic elemental
ratios of HSE that give indications where in the Solar System they
formed. However, the characteristic ratios of HSEs in the Earth's upper
mantle (for example the ruthenium/iridium element ratio of about 2)
match up with theoretical predictions for asteroids formed in the
Mercury-Venus region.




The Earth is a differentiated body, with a iron-nickel core, a
silicate mantle, and evolved silicate crust. Dr Schmidt's study shows
that the abundance ratios of HSE in the Earth's crust are much higher
than those found in stony meteorites, known as chondrites, which
represent the pristine material from the early Solar System. The ratios
of HSE found in the crust bear a much closer resemblance to iron or
stony-iron meteorites. These are fragments of larger asteroids that
have had enough internal heat in the past to form a molten metal core.
The HSE concentrate preferentially in the liquid core and at the
boundary with the solid, rocky envelope. However, the exact ratios of
the different metals depend on the physical conditions under which they
were formed.




The ratios of HSE found in the Earth's upper mantle do not
exactly match any specimens of meteorites found in collections around
the world. Close to the mantle highly siderophile element ratios are
data from the iron meteorite Charlotte.




To date, about 20 iron meteorites and about 20 stony
meteorites, called chondrites, have been identified as projectiles of
the 175 known impact craters on Earth. The projectiles for the other
135 impact craters on Earth are still unknown. No meteorites have been
identified as being formed in the region between Mercury and Venus.




Intriguingly, some of the Martian meteorites which are
probably most representative of the Martian crust also have HSE values
that resemble groups of iron meteorites and stony irons, suggesting
that a similar process took place on Mars.




Dr Schmidt said "The first meteorite to be found on Mars was
an iron meteorite, discovered by the Opportunity rover in January 2005.
Analysis of the Nahkla, Shergotty and Zagami Martian meteorites
strongly supports a genetic link with certain iron meteorites and
pallasites."




Notes: Siderophile (iron-loving) elements are a group of
high-density transition metals that tend to bond with metallic iron in
the solid or molten state. The HSE group includes rhenium (Re), osmium
Os), iridium (Ir), ruthenium (Ru), rhodium (Rh), platinum (Pt),
palladium (Pd) and gold (Au).




Adapted from materials provided by Europlanet.






Incoming Asteroid - Will Hit Earth October 7












Pennsylvania, US: Quite the mystery







Space Ice
© YORK DAILY RECORD/SUNDAY NEWS - BIL BOWDEN

Perry Foster and wife Mary Ann examine the pieces of ice that came through their roof Wednesday morning.


Mary
Ann Foster suddenly awoke about 5:30 a.m. Wednesday with a bump on her
head and insulation hanging down from the ceiling just above her bed.




The 66-year-old crawled out of bed and went downstairs to tell
her husband, Perry, that something weird was going on. Something had
crashed through the roof of their York Township home.




Her husband noticed the bump on his wife's head, and she lay down with an ice pack while he went upstairs to check things out.




What Perry Foster found in the bedroom was six pounds of ice broken
into chunks and a hole 12 inches in diameter between two joists in the
ceiling. He could even see the sky.




"I saw the ice on the floor, and I saw ice on the bed," the
68-year-old husband said. "There were chunks of ice on the bed, which
she didn't even see."




Perry Foster immediately called police, who were skeptical at
first about his story. But a York Area Regional Police officer came out
and found two big pieces of ice under a damaged ceiling tile that Perry
Foster had missed.




Ambulance personnel also came to the house and checked Mary
Ann Foster's head. She later went to see her doctor, who said it looked
OK but to be cautious.




Perry Foster placed the ice chunks into Ziplock bags and put
them into the freezer. The couple pulled them out throughout the day
for the news media to see.




The clear pieces of ice had splinters of wood and pink shreds of insulation stuck to them.




"It looks almost like quartz," Perry Foster said.




Police suggested that the ice might have come from an airplane
and that the Fosters could call the Federal Aviation Administration to
see if one flew over their house at that time in the morning. Perry
Foster said they planned to do so.




But they also wondered if it might have been a meteorite.




Mary Foster said her son-in-law found on the NASA Web site that a meteor shower had been predicted for Wednesday morning.




"If it was that, it would be kind of cool, I suppose," Mary Ann Foster said.




While it's impossible to say for sure without a scientist
examining the ice chunk, it is possible that a meteor came crashing
through the home's roof, said Dave Dombek, senior meteorologist at
AccuWeather.com.




"It is not out of the realm of possibility," Dombek said.




This time of year is the peak season for the Draconids meteor
shower, Dombek said. A meteor shower is created when the stream of icy
debris following a comet enters the Earth's atmosphere as our planet
rotates around the sun.




The Fosters plan to keep the chunks in their freezer in hopes
of getting a science professor from a college or university to take a
look at it and try to figure out where the ice might have come from.




"I don't think we have to keep it all, but we could keep maybe some of it as a souvenir," Mary Ann Foster said.




Staff writers Mike Hoover and Nichole Dobo contributed to this report.










Fire from above? -- Mysterious fire engulfs Kishtwar village in India







Village after mysterious fire

Seventy
nine residential houses, fifty eight cowsheds, eight shops and a local
Masjid was reduced to ashes in mysterious fire, which broke out in Chui
Draman village of Marwah tehsil, about 115 kilometers from here, late
last night.




Officials of police and civil administration on the
instruction of Divisional commissioner Jammu has rushed essential
supplies including cash to the village to meet emergency situation,
sources told News Agency of Kashmir.




Sources quoting officials told NAK that fire broke
out in the Chui Draman village late last night under mysterious
circumstances and it soon engulfed the entire village,
sources
said adding the initial reports available with the district
administration reveal that 58 residential houses, 58 cowsheds, 8 shops
and a local Masjid has suffered total damage in the devastating fire,
while 21 other residential structures were partially damaged.



However no report of loss of life or injury was
reported from the area, Senior officers of police and district
administration including former MLA Kishtwar Sajad Ahmed Kichloo,
Additional district development commissioner Reyaz Ahmad Zargar, SP
Kishtwar Haseeb Mughal and SDPO Kishtwar Lyakat Chowdhary were deputed
by the Divisional commissioner Jammu to the area to take stock of the
situation.




Army personnel has also reportedly reached the village early
this morning and provided immediate help to the villagers. "It was the
army which informed its unit about the devastating fire in Kishtwar", a
senior officer in the district administration said.




At least 146 structures, including 79 residential houses, 8
shops and a local Masjid were said to be damaged in the fire. However,
officials in Divisional Commissioner's office in Jammu said that the
information about the damage un-official and there was no official
details available.




"The area is far away with no road connectivity as such the
exact details of the damage could be ascertained only when the official
team, deputed to the area, returns on Wednesday", he said.




Assistant Deputy Commissioner Kishtwar Riyaz Ahmed Zargar who
was on way to Chui Draman village told News Agency of Kashmir that they
have taken essential commodities besides cash to the village to provide
on the spot relief which included essentials, blankets and cash.




It is pertinent to mention here that last year in the same
month Margi village comprising 160 residential houses, 60 cow sheds, 50
grass sheds and 2 Masjids were reduced to ashes in devastating fire.




Former Member Legislative Assembly and senior National
conference leader Kishtwar Sajad Ahmed Kichloo has urged the governor
to providing financial assistance to the affected villagers.




In a statement issued Sajad Ahmed Kichloo, has expressed shock
and grief over the loss suffered due to fire that broke down in village
Chai-draman of Warwan area of District Kishtwar the other day, in which
about 40 houses have been burnt.




He expressed sympathies with the families of the sufferers and
demanded from the government to pay ex-gratia relief of Rs. 2.00 lakh
each to the effected families and make adequate necessary arrangement
for their rehabilitation.




Sajjad Ahmed Kichloo, who reached the effected village,
distributed 200 blankets, 200 jackets, sweaters, and clothing's for
women and children and impressed upon the government to provide six
month free ration to the victims besides timber and iron sheets on war
footing for construction of their houses before the first snowfall.




Meanwhile, Senior Congress leader and former Chief Minister,
Ghulam Nabi Azad has expressed deep sorrow over the fire incident at
Wadwan, Kistwar in which 58 residential houses were gutted.




Azad has appealed the government to provide immediate relief
to the fire victims. With the commencement of the winter, Azad said
that the affected families be provided timber, tin sheets for
reconstruction of the gutted houses. He also demanded for free ration
for the fire victims.




Comment: This
seems to be very similar to the Chicago fire in the 19th century,
albeit on a smaller scale. See SOTT's analysis about its likely
cometary origin here: Comet Biela and Mrs. O'Leary's Cow









NASA's Spitzer tries to unravel mysterious comet explosion






Washington: NASA's Spitzer Space Telescope has deeply observed comet Holmes to find out why it suddenly exploded in 2007.




Observations taken of the comet by Spitzer deepen the mystery, showing
oddly behaving streamers in the shell of dust surrounding the nucleus
of the comet.


The data also offer a rare look at the material liberated from
within comet Holmes' nucleus, and confirm previous findings from
NASA''s Stardust and Deep Impact missions.




"The data we got from Spitzer do not look like anything we
typically see when looking at comets," said Bill Reach of NASA''s
Spitzer Science Center at the California Institute of Technology,
Pasadena, California.




"The comet Holmes explosion gave us a rare glimpse at the inside of a comet nucleus," he added.




Every six years, comet 17P/Holmes speeds away from Jupiter and
heads inward toward the sun, traveling the same route typically without
incident.



However, twice in the last 116 years, in
November 1892 and October 2007, comet Holmes exploded as it approached
the asteroid belt, and brightened a million-fold overnight.





In an attempt to understand these odd occurrences, astronomers pointed
NASA's Spitzer Space Telescope at the comet in November 2007 and March
2008.




By using Spitzer''s infrared spectrograph instrument, Reach
was able to gain valuable insights into the composition of Holmes'
solid interior.




In November of 2007, Reach noticed a lot of fine silicate dust, or crystallized grains smaller than sand, like crushed gems.




"Comet dust is very sensitive, meaning that the grains are very
easily destroyed," said Reach. "We think the fine silicates are
produced in these violent events by the destruction of larger particles
originating inside the comet nucleus," he added.


When Spitzer took spectra of the same portion of the comet again
in March 2008, the fine-grained silicate dust was gone and only larger
particles were present.


"The March observation tells us that there is a very small window
for studying composition of comet dust after a violent event like comet
Holmes' outburst," said Reach.




According to Jeremie Vaubaillon, a colleague of Reach's at
Caltech, pictures snapped from the ground shortly after the outburst
revealed streamers in the shell of dust surrounding the comet.




Scientists suspect that they were produced by fragments escaping the comet's nucleus after the explosion.




When Spitzer imaged the same streamers in March 2008, they were
surprised to find them still pointing the same direction as five months
before, even though the comet had moved and sunlight was arriving from
a different location.





"We have never seen anything like this in a comet before. The extended
shape still needs to be fully understood," said Vaubaillon.









Huge Meteor Crater Found Underneath Martian Ice






Martian crater
© NASA/JPL/University of Arizona

A
trough carved by erosion in Mars' north polar region. The conical mound
indicates a buried crater underneath the ice-rich soil.


New
images taken by NASA's Mars Reconnaissance Orbiter have revealed rare
evidence of an impact crater in Mars' north polar region.





Around the red planet's north pole is a feature called the north polar layered deposits, which are a series of ice-rich layers deposited over time and up to several kilometers thick.




The new images from MRO's
High Resolution Imaging Science Experiment (HiRISE) camera revealed an
odd, solitary hill rising part-way down an eroding slope of the layered
terrain.




The exposed section of the deposits is about 1,640 feet (500
meters) thick, and the conical mound is about 130 feet (40 meters)
high.



"The mound may be the remnant of a buried impact
crater, which is now being exhumed," said HiRISE team member Shane
Byrne, of the University of Arizona.




If it sounds backwards for a crater to be revealed by a mound, there's a fairly simple explanation:




The crater formed as the north polar ice layers were being
deposited. The crater itself would have been filled in by ice after it
formed.




Most of these craters are buried under the Martian surface and
inaccessible to scientists and their instruments. But this crater and
its associated ice mound were exhumed as erosion formed a trough above
and around it.




"For reasons that are poorly understood right now, the ice
beneath the site of the crater is more resistant to this erosion, so
that as the trough is formed, ice beneath the old impact site remained,
forming this isolated hill," Byrne said.




At high resolution, the HiRISE image shows that the mound is made up of polygonal blocks as big as 33 feet (10 meters) across.




The blocks are covered by the reddish dust that is ubiquitous
on Mars, but otherwise resemble ice-rich blocks seen in other images of
the north polar layered deposits.




Another new HiRISE image showed a small impact crater on the surface of Planum Boreum, or the north polar cap. This smaller crater is only about 125 yards (115 meters) in diameter.




The dearth of craters around Mars' north polar region has led
scientists to suggest that either the north polar cap is only about
100,000 years old, and therefore would have accumulated fewer impacts,
or that the craters disappear as the ice relaxes, just as imperfections
in an old window disappear as the glass relaxes.









UK: Goodness, gracious, great ball of fire!






fireball over UK
© Rowland Hobson

How an object might have looked, streaking across the night sky over Peterborough


Anyone
who witnessed a ball of flame streaking across the night sky on
Wednesday evening will be relieved to discover that the end of the
world is definitely not nigh.




UFO spotters, however, may find it something of a
disappointment that the fiery spectacle seen lingering above
Peterborough was certainly not an alien spacecraft crashing to Earth.




Since 6.30pm on Wednesday, The Evening Telegraph has been inundated with calls and e-mails from readers who saw a strange fireball cutting a swath across the heavens for several minutes.




Suggested explanations have varied from the nearly plausible to the
distinctly tongue-in-cheek, including fireworks, tricks of the light
and the result of too much time spent in the pub.




The ET, meanwhile, has been busy trying to get to the bottom
of the mystery, and after consultation with the experts we believe we
have discovered the answer.




The most likely explanation, according to RAF Wittering-based
Met Office weather forecaster and keen astronomer Julian Cooke, is that
it was an "unusually large" meteor.




"Fireballs are meteors or meteorites which are brighter than normal and although they are not common, they are not all that unusual either," he said.




"There has been a meteor shower which was at its maximum on Tuesday, and they do tend to spread over a few days either side.




"Most meteors are the size of a grain of sand or a grape pip, but
occasionally one will be much larger - maybe the size of a golf ball.




"They will burn for much longer or even explode with a flash
in the upper atmosphere, which is why they are easily visible in clear
conditions.




"What you can see is the meteor burning up as it enters the
atmosphere. It is obviously quite a sight but is certainly nothing to
worry about."




Another astronomer, 38-year-old Jason Hart, of Orton Brimbles,
Peterborough, reckons the spectacle could also have been an "iridium
flare" - when the light of the sun hits reflective surfaces on
satellites orbiting the earth, creating a streak of bright, white
light.




Dragon pub Regulars
© Paul Franks

Regulars at the the Dragon pub watched in amazement as the fireball shot through the sky


But
if the accounts of regulars and staff at the Dragon pub in Werrington
are to be believed, the phenomenon was more in keeping with Mr Cooke's
fireball explanation.




Pub manager Janek Skutela said: "It looked like a bright
orange ball, and about 20 of us went outside the pub to watch it after
one regular came in and said he could see a UFO.




"At first it shot across the sky really fast but then it went
really slowly before disappearing into the distance. All in all it
lasted about seven or eight minutes.




"We couldn't work out what it was but there were reports of a
similar thing happening a fortnight before. One of our customers saw it
but didn't say anything because he was scared everyone would take the
mickey out of him."




Tina Barnes (42), of Tanglewood, Werrington, spotted the fireball outside the Hodgson Centre next door to the pub.




She said: "At first when I saw the fireball I thought it was a
firework because of the time of year and I was waiting for it to
explode. But it continued to come nearer and nearer until it was above
my head and very visible that it was fire."









Cameras Capture 'Fireball' In The Sky: Meteor May Have Crashed In Ontario






all-sky view from Orangeville
© Western's Southern Ontario Meteor Network, University of Western Ontario

At
05:28 am on Wednesday morning, October 15, all seven cameras of
Western's Southern Ontario Meteor Network (SOMN) recorded a bright,
slow fireball in the predawn sky. In the all-sky view from Orangeville
the fireball passes from upper left (North) to right (West) ending near
the setting moon (the brightest object at upper right).


For
the second time this year, The University of Western Ontario Meteor
Group has captured incredibly rare video footage of a meteor falling to
Earth.
The team of astronomers suspects the fireball dropped
meteorites in a region north of Guelph, Ontario, Canada, that may total
as much as a few hundred grams in mass.



The Physics and Astronomy Department at Western has a network of all-sky cameras in southern Ontario that scan the sky monitoring for meteors.




On Wednesday, October 15 at 5:28 a.m., all seven cameras of Western's Southern Ontario Meteor Network recorded a bright, slow fireball in the predawn sky.




Associate Professor Peter Brown and Phil McCausland, a postdoctoral
researcher in Planetary Science, are hoping to enlist the help of local
residents in recovering one or more possible meteorites that may have
crashed.




"This event was a relatively slow fireball that made it far
into the Earth's atmosphere. Most meteoroids burn up by the time they
hit an altitude of 60 or 70 kilometers from the ground," explains
McCausland, who is heading to the region next week to investigate.
"This one was tracked by our all-sky camera network to have penetrated
to an altitude of about 37 kilometers and it slowed down considerably,
so there is a possibility that at least one and possibly several small
meteorites made it to the ground."




By knowing the trajectory from the camera observations, the
researchers can also track backwards to get the orbit of the object
before it hit the Earth.




"The meteorite was on a typical Earth-crossing asteroid-type
orbit, so we also expect that it is a stony-type meteorite," says
McCausland.




In March, the network of all-sky cameras captured video of a
meteor falling to Earth that may have crashed in the Parry Sound area.




Videos are available at aquarid physics.









US: Fireball over the Northeast






Hearing about another fireball meteor, this one spotted last evening in
the northeastern sky. Here's a report from Bowley's Quarters, in
eastern Baltimore County. Did anyone else spot this one?



"Hi there, last night about 7pm I believe - Bowleys Quarters- there
was an amazing fireball I saw through clouds traveling north in the
north eastern sky. I haven't seen anything else on this- I know meteors
are common but this was so bright and through the clouds I was amazed.
Have you heard anything on this? Thanks, Marcie"





There were more reports of a similar fireball over Colorado at around
7:00 p.m. Mountain Time last night. Not the same event, obviously, but
here's a description from an observer named Thomas Ashcraft, in New
Mexico, clipped from meteorobs.org:




"I am pleased to report that I just eye-witnessed a major fireball
event out my window. This fireball was traveling east to west, possibly
over central Colorado. It was long trailed, turquoise and green, and
shed sparks ... It looks like this fireball may have been at least 300
miles north of my location."










Meteor Flies Over Northwest Kansas






The skies over Northwest Kansas Tuesday night were like a scene from a
science fiction movie. A bright light sped across the sky, followed by
a loud explosion. Osborne County Sheriff Curtis Miner tells KSAL News
that it was not an unidentified flying object, or anything sinister. It was a large meteor.




The Sheriff says that the meteor entered the atmosphere, and as it
burnt it broke up into three pieces. It also broke the sound barrier,
causing a sonic boom that shook homes in Osborne.



According to Miner, the National Weather Service Office in Hastings, Nebraska, also received reports of the meteor.




No one was hurt, and their were no reports of damage. The Sheriff adds that pieces of the meteor have not been recovered.









US: Fireball over Colorado






This fireball occurred at 7:29 PM MDT over central Colorado. I have
received over 100 witness reports, from Casper, WY in the north,
Albuquerque, NM is the south, the Western Slope to the west, and the
Front Range to the east.




Data has been recovered from the following Network cameras:




* Cloudbait (details, video)


* Douglas County H.S. (video)






Tom Ashcraft also captured this meteor from his camera near Santa Fe, NM (video and other information).


Colorado fireball
© Cloudbait camera




The image at left is from the Cloudbait camera. The meteor is seen
passing almost straight overhead. It burned continuously, but where it
passed behind thicker clouds at the center the computer briefly
stropped recording.




Based on data from the cameras, the meteor appeared over
Colorado Springs, CO and traveled due west, ending near Cedaredge, CO.
The ground path was about 270 km (170 miles) long, and the average
speed was 34 km/s (76,000 mph).


fireball path



If you saw this event and have not made a report, please do so here.




Please check back for further information as it becomes available.









Clues To Planets' Birth Discovered In Meteorites






Meteorites that are among the oldest rocks ever found have provided new
clues about the conditions that existed at the beginning of the solar
system, solving a longstanding mystery and overturning some accepted
ideas about the way planets form.




The ancient meteorites, like disk drives salvaged from an
ancient computer, still contain magnetic records about the very early
history of planets, according to research by MIT planetary scientist
Benjamin P. Weiss.


meteorite
© Maria Zucolotto (Museu Nacional; Brasil)

A
picture of the first discovered (and therefore eponymous) angrite
"Angra dos Reis"; which was observed to fall from the sky in 1869 near
the town of Angra dos Reis in Brazil. The black; shiny face was
produced from melting of the meteorite's surface during passage through
Earth's atmosphere. Scale bar is in centimeters.




Weiss, the Victor P. Starr Career Development Assistant Professor
of Planetary Sciences in the Department of Earth, Atmospheric and
Planetary Sciences, and his five co-authors examined pieces of three
meteorites called angrites, which are among the most ancient rocks
known. The results of their study are being published in Science on Oct. 31.




The analysis showed that surprisingly, during the formation of the
solar system, when dust and rubble in a disk around the sun collided
and stuck together to form ever-larger rocks and eventually the planets
we know today, even objects much smaller than planets - just 160
kilometers across or so - were large enough to melt almost completely.




This total melting of the planet-forming chunks of rock,
called planetesimals, caused their constituents to separate out, with
lighter materials including silicates floating to the surface and
eventually forming a crust, while heavier iron-rich material sank down
to the core, where it began swirling around to produce a magnetic
dynamo. The researchers were able to study traces of the magnetic
fields produced by that dynamo, now recorded in the meteorites that
fell to Earth.




"The magnetism in meteorites has been a longstanding mystery,"
Weiss said, and the realization that such small bodies could have
melted and formed magnetic dynamos is a major step toward solving that
riddle.




Until relatively recently, it was commonly thought that the
planetesimals - similar to the asteroids seen in the solar system today
- that came together to build planets were "just homogenous, unmelted
rocky material, with no large-scale structure," Weiss said. "Now we're
realizing that many of the things that were forming planets were
mini-planets themselves, with crusts and mantles and cores."




That could change theorists' picture of how the planets
themselves took shape. If the smaller bodies were already molten as
they slammed together to build up larger planet-sized bodies, that
could "significantly change our understanding" of the processes that
took place in the early years of the nascent planets, as their internal
structures were forming, Weiss said. This could have implications for
how different minerals are distributed in the Earth's crust, mantle and
core today, for example.




"In the last five or 10 years," Weiss said, "our understanding
of the early history of the solar system has undergone a sort of
mini-revolution, driven by analytical advances in geochemistry. In this
study we used a geophysical technique to independently test many of
these new ideas. "




"Events happened surprisingly fast at the beginning of the
solar system," he said. Some of the angrite meteorites in this study
formed just 3 million years after the birth of the solar system itself,
4,568 million years ago, and show signs that their parent body had a
magnetic field that was 20 to 40 percent as strong as Earth's today.
"We are used to thinking of dynamo magnetic fields in rocky bodies as
uncommon phenomena today. But it may be that short-lived planetesimal
dynamos were widespread in the early solar system."




The paper was co-authored by Mitsui Career Development
Assistant Professor of Geology Linda Elkins-Tanton, research scientist
Eduardo A. Lima, postdoctoral researcher Laurent Carpozen, student
James S. Berdahl, and Sabine Stanley, assistant professor of physics at
the University of Toronto. The work was supported by a grant from the
National Science Foundation's Instrumentation and Facilities Program.




Adapted from materials provided by Massachusetts Institute of Technology.









Iowa, US: Residents in 3 counties report mysterious -- and loud -- noise





Danbury, Iowa -- Officials aren't sure what caused the mysterious
explosion reported by residents in three counties, but they believe it
wasn't of this earth.




"The whole house shook," said Lois Vanderbur of rural Mapleton. "We thought a tree had fallen on the house."




Woodbury County Sheriff Sgt. Doug Boetger said the explosion was
reported after 8 p.m. Tuesday by residents near the cities of Mapleton
and Danbury as well as in Ida County.




Deputies searched for evidence of an explosion or crash, but
came up empty. Their only suggestion is to look to the sky, Boetger
said.




"We found nothing damaged (and) no signs of an explosion, so we're assuming it was a sonic boom by a passing jet," he said.




Airplanes flying faster than the speed of sound can cause a sonic boom.




Today, Boetger said officials don't know what kind of plane could cause a sonic boom or where such a plane would have come from.




"They didn't come from Danbury, I can tell you that," Boetger said.




Several Air Force and Air National Guard bases are scattered across the region, but none took credit for Tuesday night's noise.




1 comment:

p said...

Yes dear
You know very well, Solar system depends on the platinum and iridium material,all the material depends on the earth.....................
Face Painting Calgary