CCNet 116/2001 - 8 November 2001

"Our estimate for the chance of a big impact contains some of the
same uncertainties as previous estimates. But it is clear that we should
feel somewhat safer than we did before we had the Sloan survey data."
--Zeljko Ivezic, Princeton University, 7 November 2001

"The Sloan study is a major advance in our understanding of the
gross asteroid belt structure. Their determination of the Earth impact
rate for killer asteroids agrees with soon-to-be-published results based
on data from the Spacewatch Project at the University of Arizona."
--Robert Jedicke, University of Arizona, 7 November 2001

"The observations are Main-belt asteroids (so far as they can tell
from one-night stands). So they are estimating the population of
NEAs by taking their estimate of MBAs and multiplying by some magic
factor (one in a thousand, probably) to estimate the number of NEAs. This
is complete, embarassing, BLATHER not worthy of notice by anyone on this
--Alan Harris, Jet Propulsion Laboratory, commenting on the
Princeton University   press release, Minor Planet
Mailing List, 7 November 2001

"Donald Yeomans, an asteroid expert at NASA's Jet Propulsion
Laboratory, said the 1-in-5000 figure has been accepted for years and is
based on a population of Near Earth Asteroids (NEAs)[...] the Sloan survey
did not study Near Earth Asteroids, but instead looked at objects
primarily in the main asteroid belt. Asteroids that far away represent no
threat to Earth over the next century and well beyond, Yeomans said.
They are orbiting the Sun in relatively comfortable fashion."
--Rob Britt,, 8 November 2001


    Ron Baalke <>

    Evening Standard, 7 November 2001


    NASA Science News, 7 November 2001

    Ron Baalke <>

    Ron Baalke <>

    Science Daily, 7 November 2001

    Andrew Yee <]

     The Planetary Society <>

     Planetary Science Research, 7 November 2001

     Giesinger Norbert <>

     Andy Smith <>


>From, 8 November 2001

By Robert Roy Britt
Senior Science Writer

There may be fewer large asteroids in the solar system than previously
believed according to a new survey released Wednesday.

Astronomers using data from the Sloan Digital Sky Survey say that the main
asteroid belt, between Mars and Jupiter, contains about 700,000 space rocks
larger than 1 kilometer (0.62 miles). Previous estimates had put the count
at around two million.

The survey involved several institutions mapping a quarter of the sky, so
the new estimate represents an extrapolation to the entire sky. The survey
data also allowed the astronomers to better gauge the size of asteroids by
studying their composition. An asteroid's size is estimated in part by the
amount of light it reflects, which is tied to the surface composition.

"The Sloan study is a major advance in our understanding of the gross
asteroid belt structure," said Robert Jedicke, an asteroid expert at the
University of Arizona.

Millions and millions of smaller rocks are thought to inhabit the asteroid

Threat to Earth?

The researchers involved in the study, led by Zeljko Ivezic of Princeton
University, said their work reduced the odds that an asteroid larger than 1
kilometer would hit Earth sometime in the next 100 years. They say the odds
had been reduced from 1-in-1500 over the next century to 1-in-5000.

But Donald Yeomans, an asteroid expert at NASA's Jet Propulsion Laboratory,
said the 1-in-5000 figure has been accepted for years and is based on a
population of Near Earth Asteroids (NEAs). Asteroids that are thought to be
near enough to our planet that gravity could lure them in sometime soon.

Scientists at NASA and elsewhere work together to find and track NEAs,
especially those 1 kilometer and larger. Experts say only rocks that large
are capable of causing global catastrophe and possibly destroying
civilizations. Between 700 and 1200 are thought to exist. Roughly 500 have
been found. All are on courses that pose no threat to Earth.

Asteroids larger than 1 kilometer are suspected of hitting Earth every
100,000 to 300,000 years, according to widely accepted estimates based
partly on a handful of terrestrial craters. But Earth tends to bury or erode
the evidence. So the estimate is based also on craters on the Moon, which do
not erode quickly but which provide a glimpse into what likely happens on

Smaller asteroids hit Earth more frequently and can wipe out a city. Objects
the size of a bus or smaller tend to burn up as they zoom through Earth's
atmosphere, and therefore they pose little or no threat.

At any rate, the Sloan survey did not study Near Earth Asteroids, but
instead looked at objects primarily in the main asteroid belt. Asteroids
that far away represent no threat to Earth over the next century and well
beyond, Yeomans said. They are orbiting the Sun in relatively comfortable

The Sloan results were published in the November issue of the Astronomical

Copyright 2001,


>From Ron Baalke <>

Public release date: 7-Nov-2001

Contact: Steven Schultz
Princeton University

Sky survey lowers estimate of asteroid impact risk

Princeton, N.J. -- The odds of earth suffering a catastrophic collision with
an asteroid over the next century are about one in 5,000, which is less
likely than previously believed, according to research published this month.

Astronomers using data from the Sloan Digital Sky Survey found that the
solar system contains about 700,000 asteroids big enough to destroy
civilization. That figure is about one-third the size of earlier estimates,
which had put the number at around two million and the odds of collision at
roughly one in 1,500 over a one hundred-year period.

"Our estimate for the chance of a big impact contains some of the same
uncertainties as previous estimates, but it is clear that we should feel
somewhat safer than we did before we had the Sloan survey data," said lead
researcher Zeljko Ivezic of Princeton University.

The results were published in the November issue of the Astronomical

The new estimate draws on observations of many more asteroids, particularly
small faint ones, than were available in previous impact risk estimates,
said Ivezic. The ability to detect faint objects in large numbers is a
hallmark of the Sloan survey, a multi-institutional collaboration that is
mapping one-quarter of the sky. While its main purpose is to look at objects
outside our galaxy, the survey also records images of closer objects that
cross the view of its telescope, which is located at the Apache Point
Observatory in New Mexico.

The survey data also allowed the astronomers to gauge the size of asteroids
with improved accuracy, which required categorizing the objects by their
composition. Asteroids with a surface of carbon -- looking like giant lumps
of coal -- are darker than those made of rock. A small rocky asteroid
therefore looks just as bright as a much larger one made of carbon.

"You don't know precisely the size of an object you are looking at unless
you know what type it is," Ivezic said, noting that the Sloan survey
provides information about the color of objects, which allows astronomers to
distinguish between carbon and rock.

Based on observations of 10,000 asteroids, the researchers estimated that
the asteroid belt contains about 700,000 that are bigger than one kilometer
(six-tenths of a mile) in diameter, which is the minimum size thought to
pose a catastrophic risk to humans and other species. The asteroid belt is
the source for a smaller group of asteroids called "near- earth objects,"
which have broken from the belt and have the potential to collide with
earth. Although they did not specifically observe near earth objects, the
researchers believe that their census of main belt asteroids reveals the
likelihood of collisions with similarly sized near-earth asteroids.

Ivezic noted that the new impact risk estimate, like most previous ones,
relies on assumptions about a single event 65 million years ago when a
10-kilometer asteroid collided with earth and killed the dinosaurs. The
researchers assumed that such impacts occur on roughly 100 million-year
intervals and used that statistic to calculate the impact odds for the more
common asteroids of smaller sizes. This calculation required knowing how
much more common one-kilometer asteroids are than 10-kilometer ones, which
was hard to measure before the Sloan data was available.

"There is a lot of uncertainty when you have a sample of only one event,"
Ivezic said, referring to the dinosaur-killing impact. "But this is the best
information we have."

Previous studies could detect only asteroids five kilometers or larger, so
astronomers had to extrapolate to estimate the number of smaller ones, said
Ivezic. The Sloan researchers found that this approach produced high
estimates. When they could actually observe them, the small asteroids were
not as plentiful as had been expected from observations of large ones.

The reason for this reduced number of smaller asteroids is an open question,
which, if answered, may offer important clues about the history of the solar
system and the factors that shaped the asteroid belts, said team member
Serge Tabachnik of Princeton.

Another valuable piece of information for scientists is the observation that
the rock and carbon asteroids are separated into two bands, said co-author
Tom Quinn of the University of Washington. The heart of the rocky asteroid
belt is 260 million miles from the sun, while the other is 300 million miles
from the sun. The sun and earth, by comparison, are 93 million miles apart.

The astronomers attribute much of the success of the study to software that
automatically identifies asteroids from among the millions of images
observed by the Sloan survey. Independent tests by Mario Juric from the
University of Zagreb, Croatia, have shown that the Sloan software finds at
least nine of every ten asteroids.

"We have only five minutes to follow the motion of an asteroid as it passes
in front of the telescope," said Robert Lupton, a Princeton researcher who
developed the software for automatic detection of asteroids. "But we have
found that we detect them very efficiently and reliably." Lupton said the
team benefited greatly from software for finding the positions and relative
movements of objects, developed by Jeff Pier, Jeff Munn, Robert Hindsley and
Greg Hennessy of the U.S. Naval Observatory.

"The Sloan study is a major advance in our understanding of the gross
asteroid belt structure," said Robert Jedicke, an asteroid expert at the
University of Arizona. "Their determination of the Earth impact rate for
killer asteroids agrees with soon-to-be-published results based on data from
the Spacewatch Project at the University of Arizona." The Arizona team based
its risk estimate on a study of near-earth objects, rather than main belt


The Sloan Digital Sky Survey ( is a joint project of the
University of Chicago, Fermilab, the Institute for Advanced Study, the Japan
Participation Group, the Johns Hopkins University, the Max-Planck-Institute
for Astronomy, the Max-Planck-Institute for Astrophysics, New Mexico State
University, Princeton University, the United States Naval Observatory and
the University of Washington.

Funding for the survey has been provided by the Alfred E. Sloan Foundation,
the participating institutions, the National Aeronautics and Space
Administration, The National Science Foundation, the U.S. Department of
Energy, the Japanese Monbukagakusho and the Max Planck Society.


>From Evening Standard, 7 November 2001

Human beings have only a small chance of being wiped out by an asteroid
impact over the next century, according to scientists.

The odds of one in 5,000 they give of such an event happening are more
comforting than a previous estimate of one in 1,500 over a 100-year period.

Astronomers analysing data from a new study called the Sloan Digital Sky
Survey have calculated that the Solar System contains about 700,000
asteroids big enough to destroy civilisation.

The figure is about a third of the size of previous estimates, which had put
the number at around two million.

Chief scientist Zeljko Ivezic, of Princeton University, New Jersey, USA,
said: "Our estimate for the chance of a big impact contains some of the same
uncertainties as previous estimates.

"But it is clear that we should feel somewhat safer than we did before we
had the Sloan survey data."

Copyright 2001, Evening Standard


>From, 7 November 2001

By Jim Banke
Senior Producer, Cape Canveral Bureau
CAPE CANAVERAL, Fla. -- Satellite operators will keep a close eye on their
Earth-orbiting spacecraft during the upcoming Leonid meteor shower, and
though the risk of damage from a stray speck of dust is greater than normal,
officials are confident there will be no natural disasters in space.

Nevertheless, if a Leonid meteoroid hits a satellite, the small grain can
destroy an imaging mirror or plow through fragile parts such as an
electricity-generating solar panel, possibly creating electrical shorts that
can disable the craft. Just the momentum imparted by an impact can throw a
satellite off course.

Especially sensitive at this time -- but not necessarily vulnerable -- are
the nation's reconnaissance, communications, navigation and weather
forecasting satellites, which are playing a key role in the United States'
efforts to combat terrorism in Afghanistan, and around the globe.

Not to worry, officials say.

"Satellites are designed with information about past storms and other things
that can happen in space," said Capt. Adriane Craig, a spokesperson for the
U.S. Air Force Space Command at Peterson Air Force Base near Colorado
Springs, Colo.

"Our satellites are robust and in the event that there is a problem we have
backup systems and contingency plans to help get them back online."

Air Force controllers at Peterson are responsible for monitoring the various
constellations of military satellite systems around the clock, Craig said,
but she wouldn't say exactly what additional measures -- if any -- are being
taken to minimize the threat from the Leonids.

"For the Leonids we have models that help us predict when the storm will
peak, so certainly (the satellite operators) can be more attentive during
that time, but we monitor the spacecraft pretty vigilantly every day of the
year," she said, politely refusing to elaborate. "I will not reveal anything
operationally about any actions we might or might not take."

The story is the same at the National Reconnaissance Office (NRO), which is
responsible for operating the many clandestine spy satellites responsible
for so much of the nation's space-based intelligence gathering efforts.

"We're working closely with the Air Force to fully understand the
implications of the Leonid storm, and we'll take precautions that we feel
are appropriate," said Art Haubold, a spokesman for the National
Reconnaissance Office. "However, we don't discuss operational details of our

It's possible that in some cases a satellite may be turned off as the best
defense against being struck by a Leonid meteoroid. However, industry
observers and others agree that military and NRO spacecraft are constructed
with extra shielding and back up systems inside the spacecraft itself,
allowing continuing operation no matter what.

"Military satellites are much more hardened and much more capable of
surviving such things than normal satellites," said Bill Cooke, a meteor
forecaster at NASA's Marshall Space Flight Center in Huntsville, Ala.

So to, Cooke said, is the International Space Station, where the current
Expedition Three crew of Frank Culbertson, Vladimir Dezhurov and Mikhail
Turin are wrapping up a four-month stay in space. Shuttle Endeavour is to be
launched Nov. 29 -- long after the Leonid's peak -- to bring up a new crew
and then return to Earth on Dec. 10.

"The space station has armor to protect it against stuff as much as an inch
across," Cooke said. "We're not expecting anything that big from this year's

Remnants from the icy comet Tempel-Tuttle, the Leonid meteor shower will
result when planet Earth sweeps through the comet's trail of debris next
week and the tiny particles encounter our atmosphere and burn up, sparking
what are commonly called shooting stars.

Earth will enter the heavier parts of the stream at about 11 p.m. EST on
Nov. 17 (0400 GMT Nov. 18). Activity will peak around 5 a.m. EST Nov. 18
(1000 GMT), when as many as 13 meteors per minute could be visible, likely
for a stretch of time that lasts less than one hour.

No larger than a grain of sand, the Leonid meteroids tend to vaporize at
about 60 miles (100 kilometers) above the surface. Satellites, however, are
orbiting the planet much higher and so could be hit by the bits before they
burned up.

Satellites that orbit between 200 and 600 miles (325 and 965 kilometers)
above Earth will face meteor rates roughly the same as what is expected to
be seen from the ground, Cooke said.

However, high-flying geostationary satellites, which sit 22,300 miles
(35,900 kilometers) above the planet will be closer to the densest part of
the debris stream. Moreover, geostationary satellites in the Western
Hemisphere would be at the greatest risk, Cooke said.

Because Tempel-Tuttle orbits the Sun in the opposite direction compared to
Earth -- a backward motion called retrograde -- its debris would hit a
satellite with much greater velocity than other meteors created by the
debris from other comets.

"It's like two cars hitting head-on," Cooke said, adding that the
penetration power is 16 times that of a normal meteor.

The greatest danger, Cooke says, is the generation of a plasma cloud -- a
byproduct of high-speed impacts that could cause an electrical short

When a meteor as fast as a Leonid strikes something, it vaporizes, creating
a cloud of plasma, or electrically charged particles. An electrical current
can then flow from one part of the craft, through the plasma cloud, and then
destroy an instrument on another part of the craft.

Few such instances have been documented.

In 1993, during the August Perseid meteor shower, a meteor hit an Olympus
communications satellite. The impact formed a plasma cloud, and the craft's
attitude control system was zapped. By the time operators could stabilize
it, they had depleted all of its attitude-control propellant and the
satellite was lost.

Copyright 2001,


>From NASA Science News, 7 November 2001

On Sunday morning, Nov. 18, 2001, sky watchers somewhere will see a dazzling
storm of Leonid meteors.  Read this story and find out how you can be one of

November 8, 2001: I'll never forget the night of November 17, 1998. It was
cold outside my mountain home at 9000 ft. The skies were crystal clear. And
it was very dark.

That is, except for the fireballs.

I was sky watching with a friend, both of us experienced astronomers.
Nevertheless, we stared upwards like novices, slack-jawed, as if we had
never seen the sky before.

We were witnessing the annual Leonid meteor shower. But these were no
ordinary Leonids. They were bright, vivid, shadow-casting fireballs. Every
five minutes or so we saw one as bright as Venus, and a fair number would
have outshined a Full Moon. Some of the most startling left behind glowing
trails of debris that lingered in the sky, twisting and turning as they were
sheared by high-altitude winds.

It was unforgettable.

In years since I've heard sky watchers refer to that event as the "1998
Leonid fireball storm." But it wasn't really a storm at all. Meteor rates
that night never exceeded a few hundred shooting stars per hour. "We define
a meteor storm to be times when observers can see 1000 or more per hour,"
says Bill Cooke from the NASA Marshall Space Flight Center. "The Leonids of
'98 -- as spectacular as they were -- were not a full-fledged storm."

But the Leonids of 2001 will be.

Cooke and other experts agree that when the Leonids return later this month
sky watchers in some parts of the world will see a display even better than
the one in 1998. Indeed, says Cooke, "what's coming on Nov. 18th could be
the biggest event since 1966 [when North Americans enjoyed a Leonid storm
numbering 100,000 shooting stars per hour]."

Observers in North America, Hawaii, Australia, and Asian countries along the
Pacific Rim will be favored for the best views of the 2001 Leonids. Meteor
rates in those places could climb as high as 8000 per hour -- not quite as
intense as the 1966 storm, but more than enough to make a sky watcher's jaw

Leonid Forecasts for Nov. 18, 2001

North America
9:00 - 11:00 UT
4:00 - 6:00 a.m. in New York
1:00 - 3:00 a.m. in Los Angeles
800 - 4000 per hour

California, Hawaii, Samoa
11:00 - 15:00 UT
3:00 - 7:00 a.m. in Los Angeles
1:00 - 5:00 a.m. in Hawaii
100 - 1000 per hour

Australia, Indonesia, Japan, east Asia
17:00 - 19:30 UT
0400 - 06:30 a.m. in Sydney
0200 - 04:30 a.m. in Tokyo
800 - 8000 per hour

Table notes: UT is Universal Time, also known as Greenwich Mean Time or GMT.
ZHR is the Zenithal Hourly Rate -- that is, the number of meteors a observer
with dark skies would see if the constellation Leo were directly overhead.
The range in predicted ZHRs reflects differences among the models of various
forecasters. [more information]

Leonid meteor storms happen when Earth passes through clouds of dusty debris
shed by comet 55P/Tempel-Tuttle when it comes close to the Sun every 33
years. This year our planet is heading for close encounters with four such
clouds. They bubbled off Tempel-Tuttle in 1699, 1766, 1799 and 1866.

"Each encounter with a dust cloud will produce an outburst of Leonids over
some part of our planet," explains Cooke. "For example, the best place to
view the 1799 meteoroids is Hawaii. That's where I'll be!" The 1766 cloud
will produce a flurry of Leonids over North America, while the 1699 and 1866
clouds will rain meteors over Australia and east Asia.

"These clouds are long and narrow like a comet's tail," says Cooke. "The
younger ones are only 10 or so Earth-diameters wide." Our chances of hitting
something so narrow and filamentary are slim. Indeed, most years in November
we miss them altogether. Earth glides between the clouds where there is only
a sprinkling of meteoroids. At such times Leonid rates remain low: only 10
or 15 meteors per hour.

"In 1998 we passed through material shed by the comet in 1333," says Cooke.
"That filament was old and somewhat spread out," so rates never climbed to
storm levels. It was nevertheless spectacular because "the smallest bits of
dust inside that cloud had been blown away long ago by solar radiation
pressure. Only the largest meteoroids remained -- hence the fireballs."

"In 2001 we're running into relatively young clouds, richer in small
meteoroids," added Cooke. "Observers from '98 who remember mostly fireballs
will be dazzled this year instead by a greater number of ordinary meteors."

Although certain parts of the world are favored for intense activity this
year, Cooke encourages people everywhere to watch the sky on Nov. 18th. "The
Leonids might surprise us," he says. Predicted outbursts might fizzle, and
activity could surge at unexpected times.

Veteran meteor watchers are wary of Leonid predictions because the science
of forecasting Leonid meteor storms is still young. The basic techniques
were pioneered only three years ago by astronomers David Asher (Armagh
Observatory) and Rob McNaught (Australian National University). They
correctly predicted a brief meteor storm over the Middle East and Europe in
1999. Then, in 2000, they and others used similar methods to forecast the
times of three more Leonid flurries. It's a promising track record, but by
no means well-established.

If you're determined to spot some Leonids this year, here is the best
strategy: Dress warmly and travel (if necessary) to a dark-sky site away
from urban light pollution. Be prepared to watch the sky between midnight
and sunrise on Sunday morning, Nov. 18th. Meteor rates will probably be low
near midnight -- although that is a good time to see beautiful Earthgrazing
Leonids -- then climb to 10 or 20 per hour by dawn. If you're lucky you
might witness a storm-level outburst and count thousands of shooting stars.

With the Leonids there are no guarantees.

No matter, the coming shower will surely send some sky watchers home with
life-long memories. "I'll never forget the night of Nov 18th, 2001," they
might recall years from now -- just as I remember the Leonids of 1998.
Others, perhaps, will gain little more than a quiet night under the stars.
One thing is certain: if you stay indoors you won't see anything!


>From Ron Baalke <>{5DDF144D-650D-4470-80EA-9E429C036EC5}

Scientists seeking help in search for meteor
November 7, 2001

CALGARY -- Researchers are hoping someone has a photograph or video of the
biggest meteor to fall in Alberta in 40 years so they can tell where it

Alan Hildebrand, a planetary scientist at the University of Calgary, says
the meteor was an asteroidal fragment that weighed five to 10 tonnes, about
1.5 meters in diameter.

Hildebrand says it was travelling at roughly 20 kilometres per second and
this was probably the biggest rock to fall on Alberta since 1960.''

The flaming rock was seen streaking north across the Alberta sky near the
British Columbia boundary on October 14th at around 2:20 a.m.

It exploded over the northern part of Banff National Park with a deafening
boom that could be heard 150 kilometers away.

Eyewitnesses reported seeing hundreds of pieces of the rock falling to the
ground, however, freshly fallen snow may delay the hunt for particles until
next spring.


>From Ron Baalke <>

 News Release
 U.S. Department of the Interior             953 National Center
 U.S. Geological Survey                      Reston, VA 20192
 Release                  Contact            Phone          Fax
 November 6, 2001         Diane Noserale     703-648-4333   703-648-6859

Crater Makes an Impact on Three Sessions at GSA

Note to Editors: Interviews with the scientists during the Geological
Society of America (GSA) Annual Meeting can be arranged by contacting
Carolyn Bell (USGS) or Ann Cairns (GSA) in the GSA newsroom in Boston at

What happens when a rock from space that's more than a mile wide slams into
the Earth at supersonic speed? Scientists from the U.S. Geological Survey
(USGS) and its partners are learning as they analyze evidence they are
recovering from cores drilled during the past two summers into the
Chesapeake Bay impact crater and surrounding structures. USGS scientists
David Powars, C. Wylie Poag, and J. Wright Horton, Jr. will present new
evidence obtained from cores and seismic surveys, on the devastating effects
this event had on the Earth 35 million years ago, during three separate
sessions at the Annual Meeting of the Geological Society of America,
scheduled for Nov. 4-8 in Boston, Massachusetts.

It's bigger and deeper than we imagined: "This comet or asteroid shot
through the Earth's atmosphere, leaving a vacuum in its wake. Then it hit,
splashing through several hundred feet of ocean and slicing through several
thousand feet of coastal plain sediments," says Powars. "It fractured the
crystalline bedrock below to at least a depth of seven miles and a width of
85 miles. Billions of tons of ocean water were vaporized and millions of
tons of debris were ejected into the atmosphere within minutes. Marine life
was decimated, and a train of giant waves of seawater inundated the land,"
explains Powers, whose talk "Structure and Composition of the Southwestern
Margin of the Buried Chesapeake Bay Impact Structure, Virginia" is scheduled
for 4:45 pm Tues, Nov. 6, Hynes Convention Center Room 202.

What's written in stone: USGS scientists are looking for clues left in the
bedrock from this extraordinary event in the deep past, to deal with an
ordinary modern-day issue: finding ground water suitable to support a
rapidly-developing region. Studies are underway to understand the impact
structure and its influence on ground water.

"We are examining the composition, age, and structure of crystalline
basement rocks beneath the Coastal Plain sediments. We are beginning to
learn more about these rocks and how they were affected by the impact
event," Horton explains.

"Crystalline rocks hidden under the blanket of Coastal Plain sediments make
up one of the most poorly understood areas of geology in the U.S., and
drilling in the impact structure has provided rare samples from as deep as
2083 feet." "Crystalline Rocks from the First Corehole to Basement in the
Chesapeake Bay Impact Structure, Hampton, Virginia" is scheduled for 2:45 pm
Thurs., Nov. 8, Hynes Convention Center Room 200.

Not a creature was stirring: USGS scientists have recently identified a zone
of silt above the post-impact fallout that is devoid of signs of indigenous
life. Wylie Poag points out that the heat from this impact must have
instantly incinerated every living thing within hundreds of miles. Poag will
review evidence -- such as fractures and deformation features in crystals,
melted rock, and tiny glass spheres -- that indicate shock pressures at
ground zero that could only have come from an impact. "From Shocked Basement
to Fallout Spherules: The Coring Record at the Chesapeake Bay Crater" is
scheduled for 4:15 pm Thurs, Nov. 8, Hynes Convention Center Room 304.

The USGS serves the nation by providing reliable scientific information to:
describe and understand the Earth; minimize loss of life and property from
natural disasters; manage water, biological, energy, and mineral resources;
and enhance and protect our quality of life.

                                *** USGS ***


>From Science Daily, 7 November 2001

University Of Cincinnati Geologist Finds Survival Benefit To Evolving After
Mass Extinctions

Cincinnati - An evolutionary group has a significantly better chance of
surviving for a long time in the geologic record if it first appears right
after a mass extinction.

University of Cincinnati geologist Arnold Miller will present his findings
Tuesday morning Nov. 6 during the annual meeting of the Geological Society
of America in Boston.

Professor Miller used a database of marine fossil genera compiled by J. John
Sepkoski to examine longevity trends throughout the Phanerozoic (the last
540 million years). In four separate cases, he found that genera first
appearing following mass extinctions survived for longer periods of time, on
average, than those that first appeared at other times.

"There was already a sense that organisms originating in the wakes of mass
extinctions were generalists with respect to their geographic and
environmental distributions," said Miller. "My analysis indicates that these
characteristics promoted evolutionary longevity."

Miller said that the trend is apparent no matter what the ultimate cause was
of each mass extinction. Genera that were more widespread, might have fared
better over the long run because of a kind of "safety in geography." If a
catastrophe decimated the individuals living in one region, then a genus
could still survive if individuals belonging to the genus also lived in
other regions.

To conduct his analysis, Miller divided the Phanerozoic into 156 "bins" or
substages. Then, he looked at the average longevity of genera originating in
each bin. Significant peaks in mean longevities occurred in the substages
following major mass extinctions in Late Permian, Late Triassic, and Late
Cretaceous-three of the "big five" extinctions of the Phanerozoic-and
following a lesser, but still significant extinction at the end of the

"These are very sharp peaks," noted Miller, who followed up his first
analysis with a number of statistical techniques to weed out artifacts in
the data set. "I was trying and trying to kill the pattern, but it wouldn't
go away."

One enigma in the analysis is that the pattern does not extend back into the
Paleozoic, the earliest of the three eras that comprise the Phanerozoic.
Although there were fairly high extinction rates during parts of the
Cambrian, Ordovician and Devonian, Miller's analysis showed no clear
relationship between extinction events and longevity in any of those
periods. "To see nothing is quite something," he said, summing up that
intriguing finding.

It is possible that, after the Paleozoic, there was a major change in the
dynamics of evolution, but Miller noted that any real explanation for the
difference between the Paleozoic and post-Paleozoic remains to be

Miller is currently working with a team of geologists worldwide to build an
online database that depicts the occurrences of marine genera throughout the
Phanerozoic, and which will incorporate data on the geography and
paleoenvironment of each occurrence. In the future, he hopes to use these
data to assess directly whether the longer-lived genera really were those
with wider geographic and environmental distributions. "We really haven't
looked definitively at the characteristics of the post-extinction players,
but with the databases we're building, we'll be able to."

Miller's work is supported by NASA's Program in Exobiology and NSF's Program
in Biocomplexity.


>From Andrew Yee <]

Geological Society of America
Boulder, Colorado

Ann Cairns, Director-Communications and Marketing, 303-357-1056


GSA Release No. 01-55

Why the Big Animals Went Down in the Pleistocene -- Was it Just the Climate?

Written by Kara LeBeau, GSA Staff Writer

There wasn't anything special about the climate changes that ended the
Pleistocene. They were similar to previous climate changes as recorded in
deep sea cores. So what tipped the scale and caused the extinction?

Russell Graham, who has been working on climate models for Pleistocene
extinction for almost 30 years, looked for triggers in a threshold effect
that did not require a unique climate change. Graham, Chief Curator at the
Denver Museum of Nature and Science, will present his research on
Wednesday, November 7, at the Geological Society of America's annual meeting
in Boston, Massachusetts.

"The end Pleistocene climate change, especially the Younger Dryas [a sudden
cold period], was a trigger that tipped the balance," he explained. "Also,
the climate model needed to answer the question of why big animals --
mammoths, mastodons, ground sloths, etc., were the primary ones to go
extinct and not the small ones. The answer to this question is the
relationship between geographic range and body size. The larger an animal,
the more real estate or geographic range it needs to support viable
populations, especially in harsh environments like those of the Pleistocene
... . Therefore, if the geographic range of animals decreased through time
then their probability of extinction would increase with time."

Graham successfully tested his hypothesis by using a computer database of
fossil ice age mammal sites linked with a geographic information system to
map changes in the distribution of species throughout time.

"This is one of the first models that does not require a unique climate
change at the end of the Pleistocene. To my knowledge it is one of the first
to look at geographic range changes of a large number of mammal species as
the primary driving factor of the extinction."


During the GSA Annual Meeting, November 4-8, contact Ann Cairns or Christa
Stratton at the GSA Newsroom in the Hynes Convention Center, Boston,
Massachusetts, for assistance and to arrange for interviews: (617) 954-3214.

The abstract for this presentation is available at:

Post-meeting contact information:

Russell Graham, Chief Curator
Denver Museum of Nature and Science
2001 Colorado Blvd, Denver, CO 80205
Phone: (303) 370 6073

Ann Cairns
Director of Communications
Geological Society of America
Phone: 303-357-1056
Fax: 303-357-1074


>From The Planetary Society <>


The Planetary Society
65 N. Catalina Avenue, Pasadena, CA 91106-2301 (626) 793-5100 Fax (626)
E-mail:  Web:

For Immediate Release: November 7, 2001

Contact: Linda Wong

Victory! House-Senate Conference Approves Pluto Mission Funding

The U.S. House and Senate conference committee acting on the fiscal year
2002 NASA appropriations have approved $30 million funding for development
of the Pluto-Kuiper Belt mission, despite opposition by the Bush
Administration. They specifically directed that "funds provided should be
used to initiate appropriate spacecraft and science instrument development
as well as launch vehicle procurement," and that NASA proceed with selection
of a team to develop the mission.

"This is a victory for public interest," said Louis Friedman, Executive
Director of The Planetary Society. "The people let Congress know that they
want NASA to explore Pluto -- the only remaining unexplored planet in our
solar system -- and Congress responded."

The Society has been leading a grass-roots effort to convince Congress to
restore the mission to the NASA budget after the Bush Administration
proposed eliminating it.

"The strong support for space exploration in the Congress is very welcome,
especially at a time when there are so many other budget pressures,"
Friedman added. He praised the House and Senate conferees noting that they
also restored full funding to the Mars program which had been threatened
with budget cuts.

If Congress had not restored the funding, the opportunity for reaching the
last unvisited planet in our solar system would have been lost for a
generation. Additionally, the chance of seeing its atmosphere before it
froze and condensed would have been lost for more than a century.

The funding, and launch vehicle constraints, probably mean that the mission
to Pluto cannot launch until 2006 -- two years later than had been hoped.
2006 is the last launch opportunity for more than a decade to utilize a
Jupiter gravity assist -- where the spacecraft would get a boost from
Jupiter -- to reach Pluto. Mission times, depending on the launch vehicle
selected, will be from 10-12 years.

The Administration is now faced with the choice of putting Pluto in its
proposed fiscal year 2003 budget, or risking another fight with Congress
next year. The Pluto mission was placed by Congress in the Outer Planets
line item, which also includes a Europa orbiter mission. The Europa mission
would be launched later than a Pluto-Kuiper Belt mission, but arrive earlier
at its destination.


Carl Sagan, Bruce Murray and Louis Friedman founded The Planetary Society in
1980 to advance the exploration of the solar system and to continue the
search for extraterrestrial life. With 100,000 members in over 140
countries, the Society is the largest space interest group in the world.

For more information about The Planetary Society, contact Linda Wong at
(626) 793-5100 ext 236 or by e-mail at

The Planetary Society
65 N. Catalina Ave.
Pasadena, CA 91106-2301
Tel:  (626) 793-5100
Fax:  (626) 793-5528


>From Planetary Science Research, 7 November 2001

--- Antarctic meteorites provide a continuous and readily available supply
of extraterrestrial materials, stimulating new research and ideas in
cosmochemistry, planetary geology, astronomy, and astrobiology.

Written by Linda M.V. Martel
Hawai'i Institute of Geophysics and Planetology

Annual collections of meteorites from Antarctica are a steady source of new
non-microscopic extraterrestrial material including lunar and Martian
samples and rare and unusual flotsam from asteroids. This article summarizes
research on new kinds of Antarctic meteorites that is not simply changing
how meteorites are classified but causing a revolution in our knowledge of
the materials and processes in the solar nebula, our solar system, and the
formation of asteroids, planets, and ultimately our world. When the
2001-2002 Antarctic Search for Meteorites (ANSMET) field party begins
scouting for meteorites on the ice this season, we will be continuing a
25-year tradition of exploration along the Transantarctic Mountains. As a
new ANSMET meteorite hunter, I will report to PSRD on this season's search
and recovery of specimens and how studies of Antarctic meteorites are
unraveling the secrets of solar system formation.

Finding Rocks That Fall From Outer Space

The U. S. Antarctic Search for Meteorites (ANSMET) program is a
collaborative effort of the National Science Foundation (NSF), NASA, and the
Smithsonian Institution. Field collection is supported currently by a grant
from the NSF Office of Polar Programs to Principal Investigator Dr. Ralph
Harvey at Case Western Reserve University in Cleveland, Ohio. NASA and the
Smithsonian Institution provide for the classification, curation, and
distribution of Antarctic meteorites. All three agencies sponsor research on
the specimens which remain the property of the National Science Foundation.
The Meteorite Working Group (MWG) reviews requests for samples by scientists
of all countries. The MWG is a peer-review committee that meets twice a year
to guide the collection, curation, allocation, and distribution of the U. S.
collection of Antarctic meteorites. 

The National Institute for Polar Research (NIPR) in Tokyo manages their own
expeditions to Antarctica and oversees the curation, allocation, and
distribution of Japanese collections of Antarctic meteorites. The Committee
on Antarctic Meteorites, which also meets approximately twice a year,
reviews all requests for meteorite samples. The samples are the property of
the NIPR, and allocations are generally only made for a period of 1 to 2

European expeditions and collection programs in Antarctica include the
Italian (PNRA) and German GANOVEX programs. European specimens currently
curated at the Open University, UK are available for study and can be
requested through the Department of Mineralogy of the Natural History Museum
in London.

These international collection programs require nothing less than strategic
trips to the ice by sturdy, trained individuals working together in a
well-coordinated way to survive and succeed in this extraordinary
environment. What motivates us to venture to a place that was only a
hypothesized landmass until it was actually sighted in 1820-21? The thrill
of living in an extreme, remote environment (likened by some to a space
outpost) with a rich history of heroic exploration, for the golden chance of
finding pieces of rock from space that tell stories of creation. From the
beginning, the Antarctic collection programs have aimed to recover large
enough numbers of meteorites each season so that something unusual might be
served up, possibly one day a sedimentary rock from Mars showing evidence of
the planet's watery history.

Tents at Meteorite Hills during the 2000-2001 ANSMET field season. This
photo was taken from the helicopter while two of the planetary geologists,
Ben Bussey and Ralph Harvey, began a six-day reconnaissance trip to ice
fields near Bates Nunatak.

Meteorites Found on the Blue Ice

Since 1976, ANSMET has recovered more than 10,000 specimens from meteorite
stranding surfaces along the Transantarctic mountains. The total number of
Antarctic meteorites is closer to 30,000 when you include Japanese
collections (beginning in 1969) and European collections. This large number
is uncorrected for pairing--when laboratory examinations show that two or
more specimens are actually broken pieces of the same rock. Antarctica (the
highest, driest, coldest, windiest, and emptiest place on Earth) has proven
to be an exceptionally good hunting ground because meteorites that have been
falling on the surface through the millennia become buried in the ice moving
slowly seaward. Where mountains or subsurface obstructions block the forward
movement of the ice, the old, deep ice, laden with meteorites, is pushed up
to the surface against the barrier. Strong katabatic winds (winds blowing
down the slopes) clear the surface of loose ice and snow and aid sublimation
and mechanical erosion which expose the meteorites on the blue ice. These
concentrations of meteorites, called stranding surfaces, are not permanent
but appear and disappear as the ice cap changes.

The Antarctic Meteorite Location and Mapping Project (AMLAMP) maintains
databases of meteorite locations for each ice field searched by ANSMET; see
the map below. The Allan Hills-David Glacier Region includes samples from
Allan Hills, Beckett Nunatak, David Glacier Icefields, Elephant Moraine,
MacKay Glacier Icefields, Outpost Nunataks, and Reckling Moraine. The
Darwin-Byrd Glacier Region includes Bates Nunatak, Derrick Peak, Lonewolf
Nunataks, and Meteorite Hills. The Beardmore Region includes Bowden Neve,
Dominion Range, Geologists Range, Grosvenor Mountains, Lewis Cliff,
MacAlpine Hills, Miller Range, and Queen Alexandra Range. The Wisconsin
Range-Scott Glacier Region includes Gardner Ridge, Graves Nunataks, Klein
Glacier, Mt. Howe, Mt. Prestrud, Scott Glacier Icefield, Wisconsin Range,
and Mt Wisting. The Thiel Mountains-Patuxent Region includes Lapaz Icefield,
Patuxent Range, Pecora Escarpment, Stewart Hills, and Thiel Mountains.
A complete set of maps, meteorite listings, and explanations are available
from AMLAMP.

Samples are identified by location (using a three-letter abbreviation), year
of collection, and unique sample number. For example, the Allan Hills
location is abbreviated as ALH, Elephant Moraine is EET, Queen Alexandra
Range is QUE, and Meteorite Hills is MET. Meteorite ALH 81005 was recovered
in Allan Hills during the 1981-1982 ANSMET field season and was the fifth
rock analyzed in the lab. It was a significant find because it turned out to
be a piece of the Moon. The next paragraphs summarize some of the
extraordinary discoveries enabled by ANSMET.

A Suite from the Moon

Scientists have identified 21 meteorites from the Moon. About half are from
Antarctica and half from hot desert regions. They recognized the first one,
ALH 81005, in 1982 on the basis of chemical, mineralogical, and isotopic
compositions. These rocks provide lunar scientists with samples from places
far from the U. S. Apollo and Russian Luna landing sites, allowing a much
better understanding of the composition of the lunar crust. More
importantly, the mere fact that impacts could blast rocks off the Moon
without melting them, gave some credence to the idea that we might also have
meteorites from Mars. See Randy Korotev's web site at Washington University
in St. Louis for more information about meteorites from the Moon.

First Martians

The idea that bits of Mars have fallen to Earth was hotly debated from the
late 1970s to the mid-1980s. The evidence centered around the relatively
young ages of a group of rocks called the SNC meteorites. They were a mere
1.3 billion years old, some even younger. Since the Moon's volcanic engine
stopped more than 2 billion years ago, the argument went, these meteorites
must come from a much large body. The logical choice was Mars. The evidence
was circumstantial.

All that changed when scientists measured the gases trapped in melted
pockets inside EET 79001, a SNC meteorite found at Elephant Moraine. The
abundances of the gases and the isotopic compositions of them were dead
ringers for the atmosphere of Mars, as measured by the Viking landers in
1976. The results stopped all arguments about where the SNC meteorites came
from--they are our first Martians. There are now 19 Martian meteorites, six
of which come from Antarctica and seven from hot deserts.
Diamond-studded Rocks

Ureilites may be the most mysterious of all the meteorites. They were named
for Novo Urei, a small rock that fell in Russia in 1886. Until people
started collecting meteorites in hot and cold deserts, only six ureilites
were known. All contained small grains of diamond (a high-pressure form of
carbon), along with graphite (low-pressure carbon). This was a startling
discovery because diamonds form at high pressure. Many scientists proposed
that the diamonds formed deep inside a large body. But as we understood the
effects of large impacts, it became clear that the diamonds were the
products of high-pressure shock waves caused by a large impact event on the
ureilite body. The key question became the source of the diamond. Was it
originally present in the rocks as graphite that crystallized along with the
silicate minerals, and was then converted to diamond by shock? Or was the
diamond forcibly injected into the rocks by an impact event?

During the past 15 years or so, the number of ureilites has increased
dramatically from only six to 110. Some of the new ones are not severely
damaged by shock and preserve the original state of the rock and its carbon
minerals. Examination showed that they contain long lath-shaped crystals of
graphite intergrown with the silicate minerals. The intergrowth clearly
indicates that the carbon was not mixed in by a shock event. The original
six ureilites fell into distinct groups on the basis of the amount of FeO
(iron oxide) in their olivine and pyroxene. This suggested that the rocks
within a group were related to each other, but unrelated to the other
groups. Analyses of the new samples indicate something different, that there
is a complete gradation in the amount of FeO, not separate groups. The
relationships among the ureilites are not so simple and researchers are
continuing to try to understand the geologic processes on the ureilite
parent body.

Leftovers From the Birth of the Solar System

Chondrites are meteorites that contain rounded objects (called chondrules)
that cooled very rapidly from a molten state. For a long time most
scientists thought chondrules formed directly in the solar nebula--the cloud
of gas and dust surrounding the primitive Sun. However, chemical and
mineralogical properties of chondrules and experiments designed to reproduce
the mineral intergrowths in chondrules showed that they could not possibly
have condensed from a gas. The condensation idea gave way in the 1980s to
the hypothesis that chondrules formed from small aggregations of dust (like
those fluffy dust balls that accumulate under your bed) that were melted by
some mysterious process in the solar nebula. Thus, meteoriticists concluded
that chondrules were secondary products.

Three chondrites found in Antarctica (ALH 85085 and QUE 94411) and the
Sahara (Hammadah al Hamra 237) are changing that view. Investigators in the
U. S. and Europe may have found direct condensates from the solar nebula in
those meteorites. Chondrules and grains of metallic iron-nickel chondrules
tell the story of heat and wind in the solar nebula. The chemical
compositions of the chondrules indicate formation from a cloud that had
become enriched in dust before being completely evaporated. When the gas
cloud cooled, the tiny droplets condensed, but were blown into much cooler
regions far from the Sun before they had a chance to acquire moderately
volatile elements such as sodium, potassium, and sulfur. They appear to have
accreted into asteroids before other processes affected them, thus
preserving the record of heating and jetting in the nebula that surrounded
the infant Sun. The results support new astrophysical theories of chondrule
and star formation. (For details on these interesting meteorites, see the
PSRD articles: Relicts from the Birth of the Solar System and The Oldest
Metal in the Solar System.)

Meteorite Bonanzas in Cold and Hot Deserts

We know that extraterrestrial materials fall randomly on Earth; it is simply
easier to find them in deserts where they are well preserved (due to lack of
weathering) and concentrated on a plain background so that they are easily
recognized. Successful meteorite searches in cold and hot deserts have
dramatically increased the number of meteorite finds. While Antarctica is
the premier cold desert hunting ground, researchers Ralph Harvey (Case
Western Reserve University), Anders Meibom (Stanford University), and
Henning Haack (University of Copenhagen) have been using remote sensing
images to look at Earth's other ice sheet, Greenland, for evidence of
meteorite stranding surfaces. Their work suggests that Greenland would be an
excellent place for future meteorite hunts. Several hot desert regions are
yielding huge numbers of meteorites, namely the Sahara Desert (Algeria and
Libya), the Nullarbor Plains (Western and South Australia), Mojave Desert
(Southern California), and high plains of Texas and New Mexico. The three
most productive areas in the Sahara are the Reg el Acfer in Algeria (at
least 320 meteorites), Dar al Gani (at least 256 meteorites) and Hammahah al
Hamra (at least 520 meteorites) in Libya. Over 200 specimens have been
collected from an unknown Saharan location (undisclosed by the private
collectors). An additional 280 meteorites have been collected in Australia's
Nullarbor Region.

To Boldly Look for Meteorites

Antarctic meteorites are collected, preserved, and documented very
carefully. They've proven their extraordinary value to science and to our
understanding of the history of the Solar System from its origin in the
solar nebula to the formation of our Sun and planets. Collecting meteorites
in Antarctica is like going on a field trip to the Moon, Mars, and
asteroids. Last year, the eight ANSMET team members recovered 740 meteorite
specimens during their two-month field trip. This season's team of ten will
return to Meteorite Hills to continue searching this portion of the vast
East Antarctic Ice Sheet. These annual systematic collection programs offer
the best chance of finding Martian meteorites and brand new types of
meteorites inspiring new research, ideas, and discoveries.



>From Giesinger Norbert <>

Dear Dr. Peiser,

It should be possible to get satellite pictures of Al Amarah from the
satellite Iconos  with 4 / 1 m resolution. At this resolution, a good sky
survey will be possible in order to decide if
it will make sense to mount an investigation on the ground. Under the
current political circumstances, it will not be easy to get all the permits
from Irak and the US (air force) to work there. Maybe CCNet should collect
some money to order the pictures - I would donate a small sum (in the range
of USD 20).

A remark concerning the scale of the impact on the middle east
civilisations: these were agrarian societies with low storage capacity so
very dependent on enough annual rain. Regarding the appearant impact of the
very local (man made) event of September 11 2001 on the "Feeling" / mood  of
significant parts of the population, I think an impact visible all over
Mesopotamia and Egypt my well have shattered the believe system and ego of
the priest cast. 

Yours sincerely

Norbert Giesinger

Price lists etc see


>From Andy Smith <>

Hi Benny and CCNetters,

This note is written to thank Arthur C. Clarke for all he has done and
continues to do, to raise the level of awareness regarding the great danger
we face, from the 100,000 or so rock bombs which are continually circling
overhead and which strike our planet, with devastating results, on a regular

We also want to thank Rick Tumlinson, the Space Frontier Foundation, Bob
Bigelow, Hugh Heffner, and the many others, including all of the CCNet
family, for the support they are giving to this important cause and we want
to send a few specifics to the Gala participants.
First, it is iimportant to remember that we have a near-miss of our orbit
about every half-hour (per Jim Scotti, at SPACEWATCH) and that the risk of
another Tunguska or larger hit, in the next 25 years is about 1 in 4! This
is the greatest technical challenge in history and we are the first
generation to have the capability to understand the danger and to prevent
most impacts. However, we are moving much too slowly.

It is imperative that we get larger telescopes (like the 8 meter super
asteroid telescope (LSST or DMT) on-line, as soon as possible and that we
support Brian Marsden and the Minor Planet Center, in their important
improvement of the global asteroid data-base. It is also important that we
call attention to the asteroid danger in such national and international
policy making groups as the Natural Hazards Caucus, of the U.S. Senate, and
that we provide basic information to all of the appropriate groups in the
United Nations and the nations of the world.

We really need an aggressive international program and modest funding, if we
are to protect our planet and all of the life on it, from this clear and
present danger. It will take both government and private support, and there
is no time to waste.

At the present, very impressive NEO discovery rate, it will take a few
centuries to get the NEO data we need. With one large and dedicated asteroid
telescope, like the DMT, we can reduce this critical time to about one
decade, according to a study by the U. S. National Research Council. The
total costs, for the needed improvements is a few hundred $million and this
is where we need the most's information to the policy makers and
funds for the critical projects. We salute the Gala and sincerly seek more
help, while there is still time.

Andy Smith
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