PLEASE NOTE:


*

CCNet 51/2003 - 13 June 2003
-----------------------------


"About 380 million years ago, a rock from space smashed into the Earth,
say geologists. They believe that the impact wiped out a large fraction
of life. The idea could strengthen the controversial connection between
mass extinctions and impacts. Up to now, the only candidate for a link is
the meteor 65 million years ago that some believe helped exterminate the
dinosaurs."
--John Whitefield, Nature Science Update, 13 June 2003


"What is unique about Ellwood's work, however, is the means he uses to
identify the different layers in the geologic record: induced magnetism.
"Everything is magnetic," he said. "If I put your finger in a magnetic
coil and turn it on, your finger will be magnetized." Ellwood uses this
phenomenon to take "magnetic signatures" of geologic samples. The
magnetic signature of a layer of earth will be the same anywhere in the
world, making it relatively easy to identify strata, if they can be
found. These signatures also make it easy to identify meteor
strikes. "The magnetic pattern associated with an impact layer is often
distinctive, making it easier to find in a thick sequence of strata," he
said."
--Lousiana State University, 11 June 2003


(1) SECOND MASS EXTINCTION LINKED TO COSMIC IMPACT

(2) EVIDENCE FOR COSMIC IMPACT IN EARLY MASS EXTINCTION FOUND

(3) METEOR IMPACT LINKED TO AN EXTINCTION OF FISH

(4) WORRYING ABOUT THE NEXT BIG SPLASH
 
(5) HEADLESS COMETS SURVIVE PLUNGE THROUGH SUN'S ATMOSPHERE

(6) BAD NEWS FOR DOOMSDAY COSMOLOGISTS: "UNIVERSE CAN SURF THE BIG RIP"

(7) RE: SIBERIAN IMPACT FLATTENS 40 SQ MILES OF FOREST

(8) IF IT HIT BOISE THERE WOULD NO LONGER BE A CAPITOL IN IDAHO

(9) PROTECTING AUSTRALIA'S FUTURE

(10) WHAT WOULD HAPPEN IF A MASSIVE OORT CLOUD COMET STRIKES EARTH?

(11) AND FINALLY: VOLCANOES, ASTEROIDS, BOMBS, BLACK HOLES ...

=============
(1) SECOND MASS EXTINCTION LINKED TO COSMIC IMPACT

Nature Science Update, 13 June 2003
http://www.nature.com/nsu/030609/030609-12.html

Rock from space might have hit life hard 380 million years ago.
13 June 2003

JOHN WHITFIELD

About 380 million years ago, a rock from space smashed into the Earth,
say geologists. They believe that the impact wiped out a large fraction
of life.

The idea could strengthen the controversial connection between mass
extinctions and impacts. Up to now, the only candidate for a link is the
meteor 65 million years ago that some believe helped exterminate the
dinosaurs.

Signs of an earlier catastrophe coincide with a disappearance of many
animals, says Brooks Ellwood of Louisiana State University, Baton Rouge:
"It doesn't mean that the impact killed off the critters, but it's
suggestive that it had something to do with it." It's not known where a
rock struck, although it's possible that traces of a crater might be
found, he adds.

Other researchers agree that there was an impact around that time, but
feel the evidence for a mass extinction is much weaker.

Rocks in Morocco laid down about 380 million years ago bear a layer of
sediment that looks like the debris from a cataclysmic explosion,
Ellwood's team found. The sediment has unusual magnetic properties, and
contains grains of quartz that seem to have experienced extreme
stresses.

Around this time, about 40% of marine animal groups vanish from the
fossil record, say Ellwood's team. Ellwood posits an asteroid slightly
smaller than the 10-kilometre rock suspected of killing the dinosaurs.
The evidence for an impact is compelling, says geologist Paul Wignall of
Leeds University, UK. And linking it to a mass extinction would be a
major finding. "The potential lethality of impacts would be greatly
increased," he says.

But it's not clear how much disappeared around the time of the impact -
the death toll may be far lower than Ellwood's team suggest, says
Wignall. He thinks palaeontologists should search the rocks for a better
picture of what happened at that time.

Even a figure of 40% is a typical extinction rate for that period of the
Earth's history, agrees palaeontologist Norman MacLeod, who studies mass
extinctions at the Natural History Museum, London. "It's not a mass
extinction, it's part of a much longer-term pattern," he says.

MacLeod doubts that mass extinctions are the result of extraterrestrial
intervention. "Impacts are quite a common phenomenon," he says. "But
they don't correlate significantly with peaks in extinction."

References
Name, A.B. Impact ejecta layer from the mid-Devonian: possible
connection to global mass extinctions. Science, 300, 1734 - 1737,
(2003).

Copyright 2003, Nature

==============
(2) EVIDENCE FOR COSMIC IMPACT IN EARLY MASS EXTINCTION FOUND

Lousiana State University, 11 June 2003

http://appl003.lsu.edu/unv002.nsf/9faf000d8eb58d4986256abe00720a51/fe4ed1a5901f7ba086256d42006edcaf?OpenDocument

Evidence for meteor in early mass extinction found
Lousiana State University Press Release
Ronald Brown, LSU Media Relations
225-578-3867

June 11, 2003

It's the stuff of science fiction movies. Bruce Willis, by a mighty
effort, saving the world from extinction by a huge meteor.

But Bruce Willis won't do it, and in our current state of readiness,
neither will anyone else (sic!). That is why LSU geophysicist Brooks
Ellwood is plumbing the geologic record, trying to correlate known mass
extinctions to meteor strikes.

"When we think about the human race and life in general, what do we
worry about? We worry about nuclear holocaust and major glaciation. Then
we worry about the giant chunks of rock that fly past Earth all the
time," Ellwood said.

"We can't see them till they're here (sic!), we can't stop one (sic!),
so the question is, how often do they hit the Earth and cause major mass
extinctions? Are extinctions often caused by impacts? If so, we want to
be sure we are prepared."

Ellwood and four other researchers have just published an article in the
journal Science in which they tie an early mass extinction to a meteor
strike. This extinction happened 380 million years ago in what is called
the middle Devonian. It was a time when only small plants, wingless
insects and spiders inhabited the land and everything else lived in the
sea. About 40 percent of all species disappeared from the fossil record
at this time.

The extinction has been known to geologists for a long time but this is
the first time it has been tied to a meteor strike. This is also the
oldest known impact that has been tied to a mass extinction.

Ellwood is quick to point out that because the extinction and the meteor
strike happened at the same time does not prove the impact caused the
extinction -- but it certainly suggests it.

One of the great difficulties in determining whether an extinction
happened on a global scale, or was a local event caused by a volcano or
some other terrestrial force, is identifying the same strata of rock at
different locations on the globe. Finding a layer of earth in Colorado,
for example, and finding that same layer in Australia is no simple task.

"The same layer of earth is exposed to different conditions in different
parts of the world," Ellwood said. "Weathering, upheavals, volcanos,
earthquakes and flooding all confuse the geologic record, making it
incomplete and open to interpretation."

The layers can also be extremely thin, he said, showing a picture of the
location of his latest research. The layer he was looking at -- near the
top of a barren plateau in the Anti Atlas desert near Rissani in Morocco
-- was about the thickness of a felt-tipped marker and only
distinguishable from the soil around it by its reddish color.

What is unique about Ellwood's work, however, is the means he uses to
identify the different layers in the geologic record: induced magnetism.

"Everything is magnetic," he said. "If I put your finger in a magnetic
coil and turn it on, your finger will be magnetized." Ellwood uses this
phenomenon to take "magnetic signatures" of geologic samples. The
magnetic signature of a layer of earth will be the same anywhere in the
world, making it relatively easy to identify strata, if they can be
found. These signatures also make it easy to identify meteor
strikes. "The magnetic pattern associated with an impact layer is often
distinctive, making it easier to find in a thick sequence of strata," he
said.

Working with LSU graduate students Steve Benoist and Chris Wheeler;
structural geologist Ahmed El Hassani of the University of Rabat,
Morocco; and Devonian biostratigrapher Rex Crick of the University of
Texas at Arlington, Ellwood was able to find high concentrations of
shocked quartz, microscopic spherules and microcrysts in this layer,
sure signs of a meteor impact. Benoist is a paleontologist and Wheeler
is an isotope geochemist; both have since moved on.

The past 550 million years are divided up by geologists into about 90
"stages." Each stage is distinguished from another by a change in the
fossil record. To date, only four of these stages show strong evidence
of a meteor strike, Ellwood's discovery being the latest, as well as the
oldest. The most recent, best known extinction is the K-T boundary at
which the dinosaurs died out, about 65 million years ago. There have
been five major mass extinctions and many smaller ones since then.

"We know that meteors have struck the Earth hundreds of times," Ellwood
said. "If I had to guess, I would say that once every 5 million years a
meteor big enough to cause a mass extinction hits the Earth.

"We could protect ourselves if we wanted. We went to the moon, we can
figure out how to destroy or deflect a meteor. All it takes is the
political will -- and an awareness of the threat."

The work of Ellwood and his team, published in the prestigious journal
Science, is a step in that direction.

=============
(3) METEOR IMPACT LINKED TO AN EXTINCTION OF FISH

The New York Times, 13 June 2003
http://www.nytimes.com/2003/06/13/science/13METE.html

By KENNETH CHANG

Just as dinosaurs died out 65 million years ago when a meteor struck the
earth, many fish and other creatures of an earlier era - about 380
million years ago - may have been similarly killed off.

Writing in today's issue of the journal Science, geologists at Louisiana
State University, the University of Texas at Arlington and the
Scientific Institute in Morocco report several lines of evidence that
point to a meteor impact that coincides with a mass extinction.

Most life was still contained in the oceans then, in the middle of the
Devonian geological period that is often called the "age of fishes." The
extinction, while global in scale, was less severe than the half-dozen
major extinctions in the earth's history.

Still, "It was probably a fairly significant impact," said Dr. Brooks B.
Ellwood, chairman of the geology and geophysics department at Louisiana
State and the lead author of the Science paper.

The research adds a new point of contention to the debate about the
influence of cataclysms from outer space on the shape of life on earth.
Dr. Rex E. Crick, a professor of geology at the University of Texas at
Arlington and another author of the Science paper, said that small
extinctions caused by numerous small meteor impacts "could be one
mechanism for driving evolution."

That is still far from clear. The end of the dinosaurs is the only one
that geologists universally agree coincides with a meteor impact. Even
there, some scientists believe that vast volcanic eruptions in India
contributed more to the extinctions.

Scientists have also reported tantalizing clues of meteor impacts
coinciding with major extinctions.

In 2001, Dr. Luann Becker, then a visiting professor at the University
of Washington, reported finding extraterrestrial gases in the geologic
layer deposited 250 million years ago. That coincides with the largest
mass extinction in the planet's history, when it is believed that 90
percent of marine species and 70 percent of backboned land animals died.
That finding, though, has not been reproduced and is widely discounted
by experts in the field.

Last year, Dr. Paul E. Olsen, a professor of earth and environmental
sciences at Columbia University's Lamont-Doherty Earth Observatory in
Palisades, N.Y., reported some signs of a meteor impact at 200 million
years ago, the time of another mass extinction. Dr. Olsen's evidence
included a modest spike in levels of iridium, an element more common in
meteors than on earth.

But scientists also know of several instances - like the formation of
the Manicougan crater in Quebec 214 million years ago - when meteors
slammed into the planet but had little if any effect on plant and animal
life.

In the new research, Dr. Ellwood and his colleagues examined samples of
rocks from Morocco. In the layer of rock 380 million years old,
corresponding to the extinction, they found grains of quartz with
microscopic lines that form when it is hit with a tremendous impact.
They also discovered spheres and crystals less than one-hundredth of an
inch wide that may be droplets of rock that melted when a meteor struck.
As further evidence, they identified elevated levels of elements like
nickel, chromium and cobalt, all associated with meteors.

The scientists did not find these indicators in rocks several yards
above or below the extinction layer. They also reported chemical signs
in carbon in the rocks that indicate rapid, widespread deaths of
organisms. "All of those things together are very strong evidence that
this is an impact layer," Dr. Ellwood said.

It is not known where the meteor hit or how large it was.

Dr. Olsen, who was not involved with the report from Morocco, said the
new evidence was more convincing than what he had presented for the
later extinction. "On a scale of 0 to 100, I would put it at 50 and
probably put my own at a 30," he said.

Dr. Ellwood said the researchers also found signs of a large iridium
spike, but because of uncertainties about the testing method, they did
not report that in the Science paper.

Dr. Ellwood also said that the researchers had found shocked quartz of
the same age in Spain, but that evidence has not been published. "I'm
pretty sure we're going to find it elsewhere," he said.

Copyright 2003, The New York Times

==============
(4) WORRYING ABOUT THE NEXT BIG SPLASH
 
Casa Grande Dispatch, 11 June 2003
http://www.zwire.com/site/news.cfm?newsid=8285093&BRD=1817&PAG=461&dept_id=68561&rfi=6

Alan Levine
 
The headline read: "Massive tsunami sweeps Atlantic Coast in asteroid
impact...." It was at that point that I wished that I had taken a
speed-reading course, because the rest of the headline read:
"...scenario for March 16, 2880."

I'm really thankful for all those folks who spend countless hours each
week with their eyeballs glued to the small end of a telescope as they
search the skies, keeping constant vigil for anything heading toward
Earth that's larger than a frozen turkey. The men and women of NASA and
the Jet Propulsion Lab, college professors and their student assistants
and even the amateur astronomers are doing a commendable job of standing
guard at Earth's edge, ready to climb the clock tower and ring the bell
at the first sign of an outer space object that's threatening our world.

But that's only reassuring to a degree, because one must wonder: If some
of the rocks spinning around in the asteroid belt should engage in a
game of billiards next week and end up knocking an eight-ball earthward
and the target was downtown Phoenix, would our celestial sentries have
enough of an advance notice to dial up a few 602 numbers and advise
Phoenicians to get out of town?

My question arises out of an incident that took place on March 8, 2002,
when an asteroid the size of a Boeing 747 passenger jet slipped past all
of the sky watchers, flew within 280,000 miles of planet Earth - just
beyond where the moon hangs out - and was finally discovered a day
later. Of even greater concern is the fact that three more days passed
before the rest of the world was notified of the event.

With that amount of miles between Earth and asteroid 2002 EM7, most
people would not consider that a close call, but in terms of the
vastness of space, it was like getting brushed back by a Randy Johnson
fastball.

According to Jeff Hecht, a journalist with New Scientist, EM7 was
difficult to see because it was moving outward from the innermost point
of its orbit approximately 50 million miles from the sun.

"When it passed closest to the Earth," Hecht wrote, "it was too close to
the sun to be visible. Asteroids approaching from this blind spot would
not be seen by astronomers. If a previously unknown object passed
through this zone on a collision course with Earth, it would not be
identified until it was too late for any intervention."

This revelation doesn't exactly have me reaching for a bottle of
tranquilizers and a hard hat. On the other hand, I don't think that I'll
be resting too comfortably in my recliner chair the next time an
ultra-light aircraft buzzes my house, because despite all of the
sophisticated glass pointing skyward and all of the incredible
technology available to map and track a large variety of outer space
objects, there is no question that the occasional maverick asteroid can
slip through the fence and trample the grass in our front yards.

This takes me back to the UCSC press release. Here we have a group of
scientists tracking an asteroid that measures nearly a mile in diameter,
known as 1950 DA, to such a fine degree that they are able to predict an
intercept course with Earth some 876 years from now and have even
managed to pinpoint the area of impact - the Atlantic Ocean, about 350
miles from Cape Hatteras, N.C.

Since the big rock will hit the water at 38,000-miles-per-hour, it will
have the same effect as a 60,000 megaton bomb. The asteroid will
vaporize on impact, creating a cavity approximately 12 miles in diameter
and reaching all the way down to the seafloor, which is about 3 miles
deep at that point.

The computer-driven scenario shows that instead of creating one big
tidal wave, the water rushing back in to fill the cavity results in a
kind of ripple effect, a series of shock waves of varying frequencies
and wavelengths that start out at about 16 feet in height and eventually
reach tsunami dimensions of from 200 to more than 400 feet. At the end
of one hour, 400-foot waves will have swept across the coasts of
Virginia and the Carolinas, and within another hour, the entire East
Coast will be deluged under 200-foot waves. Eight hours later, European
coastal cities will be looking at a wall of water somewhere between 30
and 50 feet high.

The planetary scientists at UCSC are telling us that the probability of
impact from 1950 DA is only about 0.03 percent, but they're also issuing
cautions that yet-to-be-detected space rocks pose just as much of a
threat. The supposed good news is that a NASA-led campaign to locate
large asteroids in near-Earth orbits is about half way towards its goal
of detecting 90 percent of those larger than a half-mile in diameter.

"Until we detect all the big ones and can predict their orbits," said
Eric Asphaug, an associate professor of earth sciences, "we could be
struck without warning. With the ongoing search campaigns, we'll
probably be able to sound the "all clear" by 2030 for 90 percent of the
impacts that could trigger a global catastrophe."

I don't know about anyone else, but I'm not particularly comforted by
this information, for even when we reach 90 percent efficiency 27 years
from now, what about the other 10 percent? What's really scary about all
this is the fact that asteroid 1950 DA was discovered in 1950, studied
for 17 days and then was lost for 50 years. It was rediscovered on New
Year's Eve 2001. I wonder how many more sneaky asteroids there are out
there?

©Casa Grande Valley Newspaper 2003 

==============
(5) HEADLESS COMETS SURVIVE PLUNGE THROUGH SUN'S ATMOSPHERE

Paal Brekke <pbrekke@esa.nascom.nasa.gov>

Bill Steigerwald June 10, 2003
NASA Goddard Space Flight Center
(301)  286-5017

Release 03-65

HEADLESS COMETS SURVIVE PLUNGE THROUGH SUN'S ATMOSPHERE

A run through the jungle is too easy; for the ultimate reality show
contest, try a race through the Sun's atmosphere, where two comets
recently lost their heads. The tails from a pair of comets survived a
close encounter with the Sun, even after the Sun's intense heat and
radiation vaporized their heads (nuclei and coma), an extremely rare
event photographed by the Solar and Heliospheric Observatory (SOHO)
spacecraft.

On May 24, 2003, a pair of comets arced in tandem towards the Sun,
their paths taking them to just 0.1 solar radii above the Sun's
surface, deep within the searing multimillion-degree solar atmosphere
(corona).

They belong to the Kreutz family of sun-grazing comets, often seen by
the SOHO spacecraft while diving towards their final rendezvous with
the Sun. But as in humans, twins are rare. Even more so, this pair
showed another very unusual trait: What looks like a faint tail (or
"puff of smoke") can be seen moving away from the Sun, seemingly
emanating from a point in the orbit beyond the comet's closest
approach. Normally, sungrazers simply fade and disappear at an
earlier stage, obliterated by the Sun's intense heat and radiation
pressure.

Another pair of Kreutz sungrazers with such a "headless tail" was
observed in June 1998, when the observing geometry was very similar.
But out of more than 600 sungrazing comets observed during more than
six years by SOHO, this is only the third showing any signs of such
behavior. However, this seems now likely to confirm the existence of
such comets.

"Everyone who's seen this agrees it's a very interesting
observation," said Dr. Douglas Biesecker, a solar researcher at the
National Oceanic and Atmospheric Administration's Space Environment
Center in Boulder, Colorado, and the head of SOHO's comet discovery
program. SOHO has become the most prolific comet finder in history.

The tail is most likely the dusty remains of the comet's nucleus,
being pushed out by sunlight (radiation pressure) after all the ice
in the nucleus has evaporated, thus eliminating the processes
maintaining a bright coma surrounding the nucleus. Studies of the
dust cloud may reveal clues to the size distribution of the dust
grains.

"The fact that the tail 'holds together' so well probably means that
the dust is mostly the same size," said Biesecker.

Comets are chunks of ice and dust that zoom around the solar system
in elongated orbits. This "dirty snowball" is the nucleus of the
comet; it ranges in size from a large boulder to a large city. As the
comet gets close to the Sun, solar heat and light liberate gas and
dust from the nucleus, forming the coma, which is an extensive,
bright cloud around the nucleus, and one or more tails. A comet's
dust tail can be millions of miles (kilometers) long and is pushed
away from the Sun by sunlight. Comets also have a tail of
electrically charged particles (ions) that is usually fainter and is
pushed away from the Sun by the solar wind, a thin stream of
electrified gas that blows constantly from the Sun. Both tails point
away from the Sun, even for comets that are traveling back outwards
in the solar system. Studies of the tails can reveal changes in solar
wind structure and radiance of the Sun.

SOHO is a project of international cooperation between the European
Space Agency and NASA. For images and movies of this event, refer to:

http://soho.nascom.nasa.gov/pickoftheweek/old/27may2003/

==============
(6) BAD NEWS FOR DOOMSDAY COSMOLOGISTS: "UNIVERSE CAN SURF THE BIG RIP"

Nature Science Update, 11 June 2003
http://www.nature.com/nsu/030609/030609-7.html

Alternative proposed to dark energy's cosmic doomsday.
11 June 2003
PHILIP BALL

The end of the world is not so nigh. A Spanish scientist has found a
loophole in the suggestion that there might be a Big Rip in the universe
about 22 billion years from now1.

Earlier this year, US researchers showed how the recent discovery of an
accelerating universe raises the possibility that in future everything
may rend asunder, starting with clusters of galaxies and ending with the
smallest of subatomic particles2.

Now Pedro González-Díaz of the Consejo Superior de Investigaciones
Científicas in Madrid is arguing that, even if the universe is built the
way Big Rip proponents suggest, a cosmic doomsday is not inevitable. The
universe might just go on expanding, he says.

Given the timescales involved, we needn't start fretting too much either
way. But there's no denying how terrible the Big Rip sounds. It is a
kind of breakdown of all the fundamental forces of nature, as empty
space becomes so full of energy that it overwhelms them. When that
happens, everything falls apart.

Phantom menace

The destruction begins, say Robert Caldwell of Dartmouth College in New
Hampshire, USA, and his coworkers2, about a billion years before it
ultimately ends in a Big Rip. First, gravity loses its grip at cosmic
scales, allowing clusters of galaxies to drift apart.

Sixty million years before doomsday, our own galaxy, the Milky Way,
fractures as stars slip from each other's grasp. A few months before the
end, planetary systems like the solar system will be dismembered, and 30
minutes before the Big Rip, the planets and stars themselves
disintegrate.

In the split-second before the end, atoms and molecules are torn apart,
then the particles that constitute them. Finally, space itself flies
open.

All of this is driven, the argument goes, by something known as phantom
energy, which fills all of space. The density of phantom energy
increases with time, like a bomb that grows ever bigger.

Energy bar

No one knows if phantom energy exists at all. But recent astronomical
observations hint that it might.

Five years ago, astronomers found that the universe is expanding at an
ever-accelerating rate. The cosmic speed-up suggests that space is
permeated by dark energy, creating a kind of pressure that opposes the
pull of gravity.

One explanation for this dark energy reinstates the idea of a
cosmological constant, which Albert Einstein first proposed and then
rejected in the early twentieth century. According to this hypothesis,
the universe will merely expand forever, with distant galaxies gradually
winking out of sight.

An alternative possibility is that the dark energy takes the form of
so-called phantom energy. This is more pathological than the dark energy
supplied by a cosmological constant, Caldwell and colleagues say. They
point out that phantom energy will become ever more dominant over other
kinds of matter and energy as time progresses.

In the split-second before the end, atoms and molecules are torn apart,
and then the particles that constitute them
 
Or perhaps not. González-Díaz points out that some kinds of phantom
energy can be well behaved, avoiding the blow-ups and instabilities that
lead to a Big Rip.

Dark energy can be thought of as a kind of gas filling all of space, the
density of which is proportional to its pressure. González-Díaz shows
that if one assumes that this 'gas' has certain properties -
specifically, that the speed an oscillation passes through it decreases
with time - then there is no longer a Big Rip. This might sound
contrived, but actually, González-Díaz reckons it is a more realistic
kind of behaviour than the alternatives.

To settle the debate over what's in store for the Universe, astronomers
will have to probe deeper into how it looked soon after the Big Bang,
and how it is expanding now. Questions like this are being investigated
by the Wilkinson Microwave Anisotropy Probe (WMAP) satellite operated by
NASA.
 
References
González-Díaz, P. F.You need not be afraid of phantom energy. Preprint,
http://xxx.arxiv.org/abs/astro-ph/0305559, (2003). |Article|
Caldwell, R. R., Kamionkowski, M. & Weinberg, N. N. Phantom energy and
cosmic doomsday. Preprint, http://xxx.arxiv.org/abs/astro-ph/0302506,
(2003). |Article|
 
© Nature News Service / Macmillan Magazines Ltd 2003


========LETTERS TO THE MODERATOR =============

(7) RE: SIBERIAN IMPACT FLATTENS 40 SQ MILES OF FOREST

David Dunham <dunham@erols.com]>

Has anyone obtained 1-m resolution images of the site yet, with Ikonos,
Spot, or one of the other commercial high-resolution imaging satellites?

Did anyone do that shortly after the event? Since the flash was seen by
the Air Force monitoring satellites, the location should have been known
right away - I think I remember coordinates being given in some of the
early reports.
     
     David

===============
(8) IF IT HIT BOISE THERE WOULD NO LONGER BE A CAPITOL IN IDAHO

Worth F. Crouch <choctaw@jps.net>

Recent articles about the Japanese Muses-C space probe attempting to
help scientists understand more about asteroids, and their little
meteorite cousins, delivered some bad news. Even though there are
periodic
collisions between asteroids and the Earth, two North American fireball
networks were disbanded probably because politicians see little need in
trying to predict cosmic collisions and protect the Earth.

However, the scientific community has overwhelmingly decided that
asteroid, comet, and meteorite impacts can damage Earth's civilizations.
Nevertheless, there has been a heated debate over how often deadly
cosmic collisions occur. The standard opinion is that we have nothing to
fear, because the Earth is only struck by catastrophic impacts at best
every 100,000 years. On the other hand, for years I have argued in
various scientific publications, papers, and letters, that we currently
have no way of predicting collisions or even determining their
frequencies due to insufficient data, protuberance, and mathematical
chaos. 

In 2001, I sent a letter to Professor Simonenko, the head of Russia's
atomic energy program, and wrote, "... it has not yet been determined
how many Near Earth Asteroids (NEA) there are or how many could
significantly damage the Earth. Short period comet paths are not exactly
known and the long period comets emerging from the Oort cloud are
relatively unknown and they can surprise the Earth at any time.
Therefore, randomness in space, it is currently a deficiency of our
knowledge. It then seems just a matter of time, and imperfect
predictability before the Earth will be impacted by an asteroid or comet
capable of catastrophic devastation or at least great regional damage."

Now it seems that last year, 9/25/02, a meteorite fireball fell in
Russia near the Vitim River between the towns of Bodaibo and
Balakhninsky. According to Interfax, the collision caused strong
earthquake like tremors, and flashes of light in the night's sky. The
crash site of the meteorite currently has been determined to be in the
Irkutsk region.
 
On Friday Alexander Bogun, deputy head of the Irkutsk district
administration, reported that an expedition from the Kosmopoisk
scientific organization found burnt trees covering an area of about 60
square miles, and pieces of the meteorite were found 30 miles from the
village of Mama. Without a doubt, this was the second largest meteorite
to fall in Russian, since the famous 1908 Tunguska meteorite.

The RIA NOVOSTI correspondent Edward Puzyrev wrote that the precise
coordinates have been only now fixed, because deep snow hindered work,
and now scientists can get down to a more detailed study of the
meteorite.

Robin Shepard of the Times reported that fragments of the meteorite had
apparently exploded into shrapnel 18 miles above the Earth with the
force of at least 200 tones of TNT. Moreover, "If it had hit Central
London, Britain would no longer have a capital city."

Furthermore, the little asteroid or meteorite, that wasn't expected,
could have obliterated New Your City, Tokyo, Boise, Los Angelis, or
depending on where the meteorite crashed a tsunami could have been
generated wiping out coastal cities. In addition, without a warning or
defense we face another collision at any time, because politicians and
even some scientists do not yet understand that randomness in space is
still not fully understood.

CONTACT:

Worth F. Crouch (Talako)
4875 Cedar Ridge Dr.
Auburn, CA 95602
(530) 269-3152 or (530) 906-5106
choctwa@jps.net

============
(9) PROTECTING AUSTRALIA'S FUTURE

Michael Paine <mpaine@tpg.com.au>

Dear Benny

Is there a chance of the Australian government changing its policy on
Spaceguard? To my surprise the new slogan of the ruling Liberal Party
is:
PROTECTING
SECURING
BUILDING
Australia's future

(their order and emphasis)

Wow!
yours skeptically
Michael Paine

=============
(10) WHAT WOULD HAPPEN IF A MASSIVE OORT CLOUD COMET STRIKES EARTH?

James Marusek <tunga@custom.net>

Dear Benny

Long period comets originate in the Oort Cloud, a huge sphere comprising
trillions of comets that surrounds the solar system, 20,000 to 100,000
Astronomical Units (AU) from the Sun. Long period comets will often
return after thousands or even millions of years, or not at all. The
Oort Cloud is estimated to contain 7,000,000,000,000 comets. There are 5
to 10 long period comets that approach the Sun each year. Some of these
comets are behemoths, which are several hundred miles across.

What would happen if a massive Oort Cloud comet struck the Earth? The
impactor would smash through the planet's crust and drive deep into the
planet's interior where it would release most of its energy. A large
comet, 200 miles in diameter, traveling at 100,000 mph with a density of
0.75 gm/cc would have impact kinetic energy equivalent to 3.1 x 1012
megatons of TNT. The kinetic energy from the Cretaceous/Tertiary (K/T)
impact of 65 millions years ago, that caused the extinction of many
lifeforms including dinosaurs, is estimated at 108 megatons of TNT. One
of these large comets would release 31,000 times the energy of the
impactor that caused the K/T extinction. The shock waves released inside
the planet would tear Earth's crust apart. A large part of the 1.24 x
1025 Btu of impact energy would be released as thermal energy
superheating Earth's magma.

The destruction of Earth's crust would release flood vulcanization on a
massive scale. The surface of the Earth would become a molten sea of
lava. Vulcanization would release vast quantities of compressed gases
into the atmosphere. Magma contains several dissolved gases. These gases
consist predominantly of steam (90%), carbon dioxide, sulfur dioxide,
hydrogen sulfide, hydrogen and fluorine. The impact would produce a
thick heavy atmosphere. Magma is very hot, with temperatures ranging
from 1,650 to 2,200° F. Heat release from the magma would dramatically
expand the atmospheric envelope to many times its original thickness. An
outer layer of clouds composed of water vapor and sulfur dioxide would
form around the entire planet. The outer layer would reflect most of the
solar radiation back into space, leaving the planet in continual
darkness. The inner thick layer of carbon dioxide would act as a heat
blanket, sealing and trapping the volcanic heat at the surface of the
planet. Carbon dioxide is very effective at blocking infrared radiation.
The planet's surface temperature would hover around 2000° F.

After several million years, the planet would cool down and a crust
would form. The crust creates an insulation barrier between the hot
magma and the atmosphere. Surface temperatures would drop below 1,000°
F. Clouds composed of sulfuric acid droplets would rain acid down onto
the planet and over time bleed out into surface mineralization. Sulfur
dioxide/sulfuric acid clouds would thin substantially. Sunlight,
although dim, would make its way to the planet's surface. The
atmospheric shield inhibiting photosynthesis would dissolve away. The
intense period of vulcanization on the planet would begin to come to an
end.

The planet Venus is almost an identical twin with Earth. The two planets
have approximately the same size, mass, density, volume, bulk
composition, gravity and distance from the Sun. But that's where the
similarities end. Venus has no oceans. The average temperature at the
surface of the planet is 865o F. The planet has a very heavy atmosphere,
which is composed of primarily carbon dioxide (97%). Atmospheric
pressure at the surface of the planet is 92 times that of Earth. Clouds
of sulfur dioxide float high above the surface of the planet and rain
down pure sulfuric acid. Because of its cloud cover, Venus is the
brightest planet in the night's sky. It reflects approximately 80
percent of the sunlight incident on the planet.

Venus has more volcanoes than any other planet in the solar system. Over
1,600 large volcanoes have been identified and there are perhaps a
million smaller ones. Volcanic intensity on the planet has slowed. There
are very few impact craters (~ 900) on the surface, indicating the
planet's crust is still quite young. Scientist estimated the crust was
resurfaced 300-500 million years ago. The impact craters on Venus are
quite different than those on the moon and on other planets in the solar
system. Approximately 30% of the impact craters are partially embayed
with lava. Lava floods the crater floor and in some cases breached the
crater's rim and overflows. This observation would be expected if the
planet's crust were quite thin.

Venus is presently in a stage of development analogous to the end of the
Hadean Era of the Precambrian Eon on Earth. At this stage the earliest
forms of life appeared. These hardy forms thrived in the superheated,
very toxic environment. They fed off the sulfur and the carbon dioxide
and transformed the planetary environment into a viable modern
environment of moderate temperatures, oxygen and water.

Venus is different from Earth in other ways. Venus has only minor axis
rotation. The planet makes one complete spin approximately every 243
days. Venus has an extremely weak magnetosphere. The magnetic field of
Venus is 100,000 times weaker than Earth's field. The magnetosphere
provides the planet protection from solar winds, plasma of hot ionized
gas that flows out from the sun, and from cosmic radiation. The lack of
a planetary magnetic field allows charged particles to collide with its
atmosphere. These collisions strip the outer atmosphere of the lighter
atoms, hydrogen and helium. Collisions of charged particles would also
destroy the ozone layer that protects the planet from ultraviolet
radiation. Radiation would split apart water molecules into hydrogen and
oxygen. The hydrogen would then be blown away into deep space by the
super-fast hydrodynamic escape process and lost forever. As a result,
Venus has no oceans and minimal atmospheric water vapor. Water makes up
only 0.003 percent of the present atmosphere. The water has essentially
been bled off the planet. The lack of available moisture represents one
of the key factors making it difficult for life to establish a foothold
on the planet.

What would happen if a massive Oort Cloud comet were to strike the
Earth? The answer is Venus. It's not everyday that we have the
opportunity to witness a planet being reborn. In the case of Venus, the
big question is "Will it be a stillbirth?" Or maybe a better question is
"Should we help in the delivery?"

James Marusek

==============
(11) AND FINALLY: VOLCANOES, ASTEROIDS, BOMBS, BLACK HOLES ...

Edmond Journal, 11 June 2003
http://www.canada.com/edmonton/edmontonjournal/story.asp?id=2A5F1333-446E-49D1-A5C1-E3279EA50629

Scientist says the world will end by 2020 -- one way or another

Tom Spears

Wednesday, June 11, 2003

OTTAWA - Duck, it's nearly the end of the world, says a renowned British
scientist who foresees Armageddon, or something like it, is less than 20
years away.

Sir Martin Rees, the United Kingdom's honorary Astronomer Royal, has
taken a grim look at all the bad things that science or natural
disasters could do to us. He says there's at least a 50-50 chance
something really, really bad will kill untold millions by the year 2020.

There isn't much Rees likes when he surveys the world.

He wonders, what if the terrorists who hit the World Trade Center used
plutonium weapons instead?
If such weapons seem unimaginably big, there are always tiny little
machines.

Nanotechnology is the art of making machines the size of a single
molecule. Most scientists talk about using it to make useful things such
as little sensors, or gadgets that will deliver drugs to precise targets
in our cells.

Rees takes the gloomier view that nanotech machines will replicate
themselves on an out-of-control scale.

That is, if we aren't hit already by natural disasters such as
volcanoes.
Sure, we've had lots of those in the past, but the veteran astronomer
hypothesizes about a "super-volcano" so huge that its smoke blots out
the sun and makes Earth unlivable.

There's one waiting to pop right now under Yellowstone National Park in
the U.S., he believes.

Speaking of climate, it may become hot enough to evaporate huge amounts
of fresh water and transform farmland into wasteland.
That is, if we aren't hit first by an asteroid.
One wiped out the dinosaurs 65 million years ago. Are we overdue?
Martin's worried sick about that.

But not as sick as bioterrorism will make us if we genetically engineer
nasty bugs and they escape and breed and spread before we have a chance
to build up immunity to them. But even bugs won't stand a chance from a
black hole.

Scientists who study matter may some day squash matter together in such
a dense mass that it forms a black hole that grows bigger and bigger
until it just sucks in all of Earth and anything else in this part of
space.

Or so goes Rees's apocalyptic theory.

His musings blur an old line between astrologers, who foretell the
future, and astronomers.

Rees is 60 years old, a theoretical astrophysicist and black hole expert
at Cambridge University. He has been busy writing a book, just
published, with the cheery title Our Final Hour.

Buy it before 2020.

© Copyright 2003 Edmonton Journal

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