PLEASE NOTE:


*

CCNet 101/2002 - 2 September 2002
---------------------------------

 
   "In popular perception, dinosaurs died out because of the asteroid.
   But the actual evidence from the fossils doesn't support that in the
   way some people like to think."
      --Angela Milner, Natural History Museum, 31 August 2002


   "A large impact is not something we expect to happen in our lifetime,
   in our children's' lifetime, or even our grandchildren's' lifetime. It
   would be very bad luck if it did happen. But it could happen at any
   time."
     --David Hunter, 31 August 2002

 
   "Science-fiction writers are queueing up to be associated with 9/11
   (see Giles Foden in these pages last week). Hot on the heels of
   speculation that Osama bin Laden might have been influenced by Isaac
   Asimov's sci-fi novel Foundation (1951) comes a letter from Arthur C.
   Clarke in New Scientist. Clarke notes that the European Space Agency
   is sponsoring a project called Spaceguard. "I invented this name," he
   writes, "for the first chapter of Rendezvous with Rama (1973), which
   is now optioned for filming. I'm still spooked by the fact that the
   asteroid impact that triggers the story is dated 11 September."
        --The Guardian, 31 August 2002


(1) "K/T MASS EXTINCTION JUST POPULAR MYTH: CLIMATE CHANGE KILLED
    DINOSAURS - NOT COSMIC IMPACT"
    BBC News Online, 31 August 2002

(2) SUDDEN IMPACT: WHEN WILL EARTH TAKE ITS NEXT HIT FROM AN ASTEROID?
    The State Journal-Register, 31 August 2002

(3) SPACE ROCK DEBATE ROLLS ON
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(4) SKYWATCHERS SEARCH FOR ASTEROIDS
    Andrew Yee <ayee@nova.astro.utoronto.ca>
 
(5) CHANCE SMALL FOR HEAD-ON COLLISION
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(6) COSMIC AIRBAG COULD SAVE THE PLANET
    New Scientist, 29 August 2002

(7) WOULD GIANT AIR BAG STOP KILLER SPACE ROCK?
    CNN, 31 August 2002

(8) TEENAGER 'STRUCK BY METEORITE'
    Ananova, 27 August 2002

(9) RE: "IMPACT AND THE END OF THE ROMAN EMPIRE IN THE WEST"
    Mike Baillie <m.baillie@qub.ac.uk>

(10) AND FINALLY: ....... :-)
     Northern Territory News, 31 August 2002

==============
(1) "K/T MASS EXTINCTION JUST POPULAR MYTH: CLIMATE CHANGE KILLED
    DINOSAURS - NOT COSMIC IMPACT"

>From BBC News Online, 31 August 2002
http://news.bbc.co.uk/1/hi/science/nature/2225779.stm

Dinosaurs could not cope with climate change

Cold was killing dinosaurs long before the asteroid commonly thought to
have been their downfall hit, according to scientists.

That asteroid 65 million years ago in the Cretaceous period was probably
the "final straw".

But Australian experts say up to half of all dinosaurs were gone by
then, because the climate had got too cold for them to bear.

Fossil evidence from the Drumheller valley in Alberta, Canada, covering
7m years before the asteroid hit, shows that average temperatures
dropped from 25C to 15C.

Many cold-blooded reptiles such as crocodiles, turtles and many large
plant-eating dinosaurs died out as the climate cooled.

Oxygen isotope readings from fossils show the temperatures at which they
formed, so scientists can track the climate change over time.

They found there was also a decrease in annual rainfall over the period
where species died out.

But, David Eberth of the Royal Tyrell Museum of Palaeontology, who
carried out the research, said it was unclear why dinosaurs were so
dramatically affected.

Body temperature

Dr Angela Milner, associate keeper of palaeontology at the Natural
History Museum, told BBC News Online: "A lot of people have suggested
that climate change is the reason dinosaurs started to decline.

"But this research, using isotopes records, shows categorically there
was quite a big temperature drop."

Dr Milner said cold-blooded dinosaurs would have been able to bear a
colder climate for a short time because their size would have meant they
could keep their body temperature constant.

But they would have been unable to cope for very long.

Dr Milner added: "In popular perception, dinosaurs died out because of
the asteroid. But the actual evidence from the fossils doesn't support
that in the way some people like to think.

"But that may well have been the final straw that broke the remaining
camels' backs."

The research is featured in Chemistry and Industry.

Copyright 2002, BBC

============
(2) SUDDEN IMPACT: WHEN WILL EARTH TAKE ITS NEXT HIT FROM AN ASTEROID?

>From The State Journal-Register, 31 August 2002
http://www.sj-r.com/sections/news/stories/N08312002,k.asp

By SCOTT HILYARD
COPLEY NEWS SERVICE

These two things we know, astronomically speaking: An asteroid will one
day strike Earth.

It won't be the first time.

As if we don't have enough to worry about - the West Nile virus,
wildfires, shark attacks, a new Adam Sandler movie - now comes this. A
big asteroid passed within 75,000 miles of Earth last month which, in
interstellar proportions, is like a mosquito buzzing between your upper
lip and nose. Three months earlier, another one, named 2002 EM7, passed
about three times as far away.

Both so-called near misses had something in common: all those telescopes
trained on space and not one saw them coming. They're not easy to spot
in the first place and they approached from the "blind spot" near the
sun. Neither asteroid was detected until after it had passed Earth by,
according to news reports following the June 17 discovery.

"There are between 1,000 to 2,000 asteroids out there that cross the
Earth's orbit," said Tom Willmitch, the planetarium director at Illinois
State University. "Therein lies the threat."

The threatening cosmic bodies to which Willmitch refers are little more
than big rocks drifting in space. Generally, they are bigger than
meteors and differ from comets in that they are comprised mostly of
rock, metals and silicates. Comets are big frozen iceballs.

"Asteroids are the building blocks of the solar system, leftover
material from when the planets were being formed," Willmitch said. "They
can be big - miles across - or much smaller and they have been around,
drifting in space since the solar system was born, 4.5 billion years
ago."

Ceres is the largest known asteroid, with a diameter of 570 miles. It
was discovered in 1801 and its orbit lies safely in the asteroid belt
beyond Mars and is no threat to Earth, Willmitch said.

The number of Earth-approaching asteroids keeps growing. Just 20 years
ago, astronomy textbooks consistently pegged the total at around 50, but
the number has jumped, especially dramatically in the past five years,
to the now commonly accepted 1,000 to 2,000.

But even that number continues to be extremely fluid, Willmitch said.

Does that mean there could be 5,000 collision-course asteroids out
there? 10,000? 20,000?

"Those kinds of numbers would be far less likely," Willmitch said.

Each of these asteroids will suffer one of only two possible outcomes.
Either it will crash-land into one of the terrestrial planets, or it
will be flung out of the gravitational pull of the inner solar system.
This is according to the study of noted asteroid expert Eugene
Shoemaker, who died in 1997.

"The Earth-crossers cross into the Earth's orbit as they revolve around
the sun," Willmitch said. "Three in the last six months have whizzed
past our ear."

The size of the asteroid dictates the level of damage it would do to the
Earth. An asteroid in Tunguska, Siberia, on June 30, 1908, did not
survive entry into Earth's atmosphere and still managed to explode with
the equivalent force of a 10-megaton bang, flattening a large forest.
Experts say the asteroid named 2002 MN, which passed closely by Earth
just last month, probably was large enough to cause similar devastation.

Another asteroid in Vladivostok, Siberia, on Feb. 12, 1947, created 106
craters and pits up to 30 yards across. A crater near Winslow, Ariz.,
caused by a relatively small asteroid, is about 4,000 feet across.

The concern among scientists is that an asteroid hit will be mistaken
for a nuclear attack. Subsequently, retaliatory missiles would fly
before anyone discovered the destruction was caused by a natural
phenomenon.

So how serious is the threat?

"A large impact is not something we expect to happen in our lifetime, in
our children's' lifetime, or even our grandchildren's' lifetime. It
would be very bad luck if it did happen," said asteroid hunter David
Hunter in a Science magazine interview. "But it could happen at any
time."

The prevailing scientific thought is that an asteroid collision with
Earth likely killed the dinosaurs, Willmitch said. The dinosaurs weren't
wiped out by the direct hit of what was likely a very large asteroid,
but by the ensuing climate changes the catastrophic collision caused.

That type of mass extinction has happened four other times in Earth's
history, some scientists believe. An asteroid that size collides with
the Earth on average once every 100 million years, which means,
Willmitch said, crunching the numbers, that Earth is "due" on average
for the big one sometime within the next 35 million years.

"Or tomorrow afternoon," he said. "There's just no way to say."

Using the latest asteroid-searching technology, NASA's Near Earth Object
Program has calculated that an asteroid called 1950 DA has the best
chance of any known of colliding with this planet. They've got it
narrowed down pretty well.

March 16, 2880. The time of day, apparently, is still being calculated.

"This is not something to worry about," said Jon Girogini, a senior
engineer at NASA's Jet Propulsion Laboratory in California, in the April
5 edition of the journal Science. "We're showing that searches with
optical telescopes and follow-up observations with radar telescopes can
provide us centuries of advance notice about potential close encounters
of asteroids with Earth. That's plenty of time to consider the options -
35 generations, in fact."

And, Willmitch said, options do exist. Just as cosmic nudges occur in
space that move asteroids into potential Earth collision orbits, so,
too, could a man-made nudge - nuclear or whatever future ability mankind
might create - could save the planet.

"It's not nutty science fiction to think that man can do something to
alter the course of these asteroids if one threatens," Willmitch said.

That's the good news.

"Of course, that's just for the one's that we know are coming," he said.

That's the bad.
 
All Content The State Journal-Register
 
============
(3) SPACE ROCK DEBATE ROLLS ON

>From Andrew Yee <ayee@nova.astro.utoronto.ca>

[ http://www.floridatoday.com/news/space/stories/2002b/090102debate.htm ]

Saturday, August 31, 2002, 8:59 PM EDT

Space rock debate rolls on

Experts discuss options to protect Earth from hit

By John Kelly, FLORIDA TODAY

The dinosaurs didn't know what hit them.

Humans might know that a three-mile wide asteroid is heading
right for Earth. We might even know the date, years or decades
before, when the big rock will bore through our atmosphere and
slam into Earth with enough force to envelope the planet in
dust, water, fire or some deadly combination.

Science and technology make it possible to spot near-Earth
objects, track their orbits and even predict where they might
go. And advances in spacecraft, propulsion and weaponry might
make it possible for humans to do something to divert or
destroy a dangerous asteroid, comet or meteor.

More important than those advances, however, might be
attitudes. Serious minds in the science, space and defense
communities once laughed off investing time and money in
systems designed to protect the planet from the incredibly
remote possibility of a devastating asteroid impact, but
dozens of experts in those fields will gather this week in
Washington to discuss those very questions.

For the next few days, people from prestigious universities,
aerospace companies, think tanks, NASA and the Air Force will
hole up at a suburban Virginia hotel for the NASA-sponsored
"Workshop on Scientific Requirements for Mitigation of
Hazardous Comets and Asteroids."

The biggest question to be posed, according to University of
Maryland astronomy professor Michael A'Hearn, is: "What is it
we need to know about these bodies before we can intelligently
decide what we need to do to protect ourselves from them?"

With increasing frequency, astronomers are publicly reporting
near-Earth objects whizzing past the planet or making onerous
predictions regarding humongous asteroids which might -- or
might not -- be on a collision course with Earth.

It's not because there are more objects, but because the
technology for spotting such objects is better and more people
are using it to watch the sky. NASA is tracking near misses
and potentially hazardous objects. Similar operations, run by
professional and amateur astronomers, are springing up around
the world. The U.S. Air Force may develop an early warning
system. As capability increases, more people in the science
community are pushing policy-makers to at least consider
defense options.

"Our preparations are poor and undeveloped," said Clark
Chapman, a Colorado-based scientist with the Southwest
Research Institute's space studies department. "About all
that we're doing is looking for asteroids with some
telescopes, and beyond that there is essentially no funded
effort to plan for this kind of unlikely event, although
there are people who are thinking about it, you know,
evenings and weekends."

The odds of a globally devastating impact in the next 100
years are about 1 in 5,000. But while some use that to
denounce planning any specific defense system, Chapman said
leaders need to continue research and discuss options "so
if we did need to do something we wouldn't have to start
from scratch."

There is no shortage of ideas, including some you might have
seen at the local movie theater. Yes, there are proposals
to follow the lead of Bruce Willis in Armageddon and Robert
Duvall in Deep Impact by using a nuclear-type blast to
deflect or destroy a potentially dangerous space rock. Another
suggestion is a complex network of laser-firing satellites.
Yet another calls for somehow nudging the object to change its
orbital course a few centimeters, enough to keep it safely
away from the path to Earth.

But according to many people going to this week's conference,
most of the ideas are just ideas. Instead, the most important
development this week will be serious sharing of information
between diverse groups of people and organizations who will
play a role in further research and who might someday be
called upon to assist in any effort to avert a real crisis.

"There has been a lot of discussion about mitigation, but this
workshop is probably the most serious and objective approach
to the problem to date," said Dan Scheeres, a University of
Michigan researcher devising ways to get spacecraft close
enough to a moving asteroid to monitor, test or even land on
it. "A lot of the good scientific work that touches on this
issue has been more focused on the hazard, which is questions
like how big does it have to be before you get a global
effect."

But don't expect the conference to prompt a movement in the
scientific community to push for a multibillion-dollar defense
system, said University of Illinois professor Bruce Conway.

"What is going to come out is a call for a lot more
exploration," Conway said. "We don't know very much about
these objects. We've only been to a handful of asteroids.
We've only landed on one. We don't have a very good idea of
what they are made of or how fragile they are. Some people
think they are a solid rock. Others think they are an
accumulation of a lot of smaller pieces that would fragment
if we push them around."

That's why more asteroid-studying missions must be done
before anyone can know if defense systems are needed and
what strategy would work best, scientists said. Others are
calling for further improvement of the monitoring systems,
or even some formalized cooperative warning system where
science, space and defense agencies in different countries
could better share information.

Alan Harris, of NASA's Jet Propulsion Laboratory in California,
said research should continue into all relevant areas because
much of it has other scientific value.

For example, better propulsion systems might be needed to
travel to and work in close proximity to asteroids and other
near-Earth objects. But the value of such development would
be felt throughout the space industry too. That research is
a higher priority than investing what could be billions of
dollars in a single defense system for something that might
not happen in the next million years.

"The cost and/or risk of building a mitigation system in
advance of need outweighs the benefit of having it," Harris
said. "However, if an asteroid on an impact course were to be
found, I'd be on the doorstep of the weapons labs first thing
in the morning to order up a remedy. But not before."

Copyright 2002 FLORIDA TODAY.

=========
(4) SKYWATCHERS SEARCH FOR ASTEROIDS

[ http://www.floridatoday.com/news/space/stories/2002b/090102asteroid.htm ]

Saturday, August 31, 2002

Skywatchers search for asteroids

Only handful of people stand between Earth and disaster

By Chris Kridler, FLORIDA TODAY

There's a select club of people who are awake while you're
asleep, scanning the skies all night for a bright spot or
smudge that could be the next big rock that threatens Earth.

One scientist said there are more people working in your
typical McDonald's than there are working full-time to save
the planet with their telescopes.

Asteroid hunters and comet hunters have to deal with a vast
universe, low budgets, highly competitive quests for grants
and bone-headed media reactions to initial discoveries that
suggest impending doom before the findings are refined by
mathematics and time.

"I think you can expect more reports of potential impactors
as time goes on, because more asteroids are being discovered,"
said Robert McMillan, principal investigator for the
Spacewatch project, which uses two telescopes 45 miles
southwest of Tucson, Ariz., to scan.

"So the ones that zing past the Earth at relatively close
distances have always been doing that, it's just now we've
become more aware of it."

Under a mandate by Congress, partly spurred by the spectacular
collision of comet Shoemaker Levy 9 with Jupiter in 1994,
skywatchers are looking for the kind of rock that could make
us extinct.

Efforts such as Spacewatch and the joint NASA-Air Force
Near-Earth Asteroid Tracking project in Maui, Hawaii, have
to sort through a lot of rocks to find what McMillan calls
"potentially hazardous asteroids."

50 worth watching

Spacewatch spots about 100,000 asteroids a year, but most are
in the solar system's main asteroid belt. Only about 50 are
near-Earth asteroids.

They send their discoveries to the Minor Planets Center in
Cambridge, Mass., and post them on technical Web sites. Other
professional and amateur astronomers can follow up on the
discoveries by tracking the objects' orbits and refining
predictions of where they'll end up.

Sometimes, though, a scientist won't communicate a finding
clearly, or a journalist will rush ahead with a story about
an Armageddon rock, before additional calculations can rule
out an Earth-crossing orbit.

"It's a more complicated problem than blaming some
journalists," said asteroid expert Clark Chapman, with the
Southwest Research Institute in Boulder, Colo. "First, the
issue is inherently difficult for people to grasp,"
particularly the enormous odds against a collision.

The most recent example was reporting on asteroid 2002 NT7,
which caused a media frenzy in Britain when initial
calculations showed it had a chance of hitting Earth on
Feb. 1, 2019. Later calculations showed it wouldn't.

Such reversals hurt the credibility of scientists, who really
aren't trying to get attention by crying doom, observers say.

"I worry about it. I encounter people on the street who are
kind of unhappy about this stuff," Chapman said. "I was just
in my dentist's chair yesterday morning, and he said, 'What's
with this asteroid that was going to hit the Earth?' I think
scientists as a whole need to work to preserve their
credibility, because there's so many voices in our lives
saying so many foolish things, people who are peddling so
many kinds of crazy things, pseudo-scientists and what-not."

Even though they always go through a process of refining their
forecasts, "it certainly comes across like we're making
mistakes," he said.

Meanwhile, skywatchers labor while engaging in "friendly
competition" for scarce grants, some of which are too
short-term to make long-term plans.

"It's a very small community," Chapman said. "The total
funding in the world is mainly the funding by NASA, which is
a couple of million dollars."

More funding could help astronomers find smaller asteroids
that might not cause a global crisis but could, say, take
out South Florida.

"There are arguments for increasing the coverage down to
smaller asteroids," McMillan said. "Currently the goal of
NASA is to find 90 percent of Earth-approaching asteroids
larger than 1 kilometer within 10 years of surveying, but
of course, asteroids that are smaller than that can still
do a great deal of damage."

The problem is that expanding the effort would be taxing and
expensive, said Richard Kowalski of Zephyrhills, moderator
of the online Minor Planet Mailing List, which is frequented
by asteroid hunters.

"You would have to spend billions and billions of dollars (sic!)
per year, and the threat is not that large, so it's hard to
justify spending that money," he said.

Amateur astronomers help fill the gap, and what they spend
is equivalent if not greater than funding given to official
searchers, Kowalski said.

When it comes to amateurs, "in the case of comets, they're
a crucial part of it," said Michael A'Hearn of the
University of Maryland, the principal investigator for the
Deep Impact comet probe.

"The professional surveys are doing very well at what
they're trying to do, which is finding and cataloging all
the asteroids," said A'Hearn, who will be speaking at a
NASA-sponsored asteroid conference in Virginia this week.
"People often assume that comets will be found as a natural
byproduct of all of that, but the point is, they won't be."

It's difficult to track comets, because many have much longer
orbits than asteroids do.

"The asteroids are the largest part of the hazard," A'Hearn
said, "but we just don't know what fraction of the hazard is
due to comets. It's certainly less than half, and it could
be as small as one percent."

"To satisfactorily find comets in time to do anything about
it is a major challenge," said Chapman, who also is speaking
at the conference. "It's probably technically possible to do,
but it's nothing that's at all easy. It would maybe involve
launching major space telescopes out in Jupiter's orbit."

WEB EXTRA:

* Near-Earth Asteroid Tracking
  http://neat.jpl.nasa.gov/
* The Spacewatch Project
  http://spacewatch.lpl.arizona.edu/
* NASA page on asteroids and comets
  http://nssdc.gsfc.nasa.gov/planetary/planets/asteroidpage.html
* Minor Planet Center
  http://cfa-www.harvard.edu/iau/mpc.html
* Minor Planet Mailing List
  http://www.bitnik.com/mp/
* Clark Chapman's home page (with asteroid links)
  http://www.boulder.swri.edu/clark/clark.html
* NASA page on impact risks
  http://neo.jpl.nasa.gov/risk/
* Deep Impact comet mission
  http://deepimpact.umd.edu/mission/index.html
* Workshop on Scientific Requirements for Mitigation of Hazardous
  Comets and Asteroids
  http://www.noao.edu/meetings/mitigation/index2.html

Copyright 2002 FLORIDA TODAY.

===========
(5) CHANCE SMALL FOR HEAD-ON COLLISION

[ http://www.floridatoday.com/news/space/stories/2002b/090102hit.htm ]

Saturday, August 31, 2002

Chance small for head-on collision

Direct hit would wipe out half world's population

By Kelly Young, FLORIDA TODAY

CAPE CANAVERAL -- Statistically speaking, a person has just as
good a chance of perishing from a plummeting asteroid as he
does of dying in a plane crash in his lifetime.

But the numbers are slightly misleading.

If a large enough asteroid hits Earth, as they are known to do
every 100 million years or so, it could wipe out half of the
planet's population. Whereas if an airplane crashes, as
several do annually, it can kill hundreds of people. The odds
actually even out.

"It's hard to compare the two because they're on such different
time scales, ... the consequences are so different," said
asteroid hunter Jim Scotti, an astronomer with the Spacewatch
group at the University of Arizona.

A November study published in the Astronomical Journal showed
the odds of this planet being hit with a civilization-ending
asteroid in the next 100 years are about one in 5,000. This
is less likely than scientists had previously calculated.

Spread out over millions of years, astronomical odds of
being killed by an asteroid can be difficult to comprehend.

"We're talking about probabilities people don't get," said
Clark Chapman, institute scientist for Southwest Research
Institute in Boulder, Colo. "We're not wired to understand
these low probabilities, which is why state lotteries are
so successful."

For the record, each time a Floridian buys a state lottery
ticket, he has a one in 23 million chance of winning the
jackpot.

In comparison, your lifetime odds of dying from an injury are
just one in 23, according to a 1998 report by the National
Safety Council.

The Sloan Digital Sky Survey has software that robotically
scans the skies for asteroids and found that the solar system
houses about 700,000 asteroids big enough to wipe out Earth
life. Earlier estimates were three times that figure. Here is
how astronomers assign risk to an approaching object like an
asteroid or comet:

When they spot a new asteroid, they try to observe it for as
long as they can. Based upon the swath the asteroid cuts
across the sky in about five minutes, astronomers try to
estimate what its orbit is. But because they've only seen
the orbit once, the orbit is fairly uncertain and may change
as they make more observations.

"The more observations you have the better determined the
orbit is in some distant date in the future," Scotti said.

If they find that its orbit around the sun may one day
intersect Earth's path, then the astronomers have to figure
out whether they would ever be at the same place at the
same time, which could result in tsunamis, climate change
or just an all-out mass extinction.

"This hazard is one element of a whole panoply of risks and
hazards that people are walking around facing these days,
from carcinogens, from terrorists," Chapman said. "There
should be more education, informal education like through
science journalism, and formal education, like through
science classes" to teach people how they should respond
when hearing about such hazards.

Obviously, many things in our daily lives are risky. The
National Center for Statistics and Analysis reported that
people faced a one-in-6,761 chance of being killed on U.S.
roads in 2001. That's just for one year. The asteroid risk
of one-in-5,000 is spread out over 100 years.

And besides, there's actually a chance people could survive
the space rock onslaught.

Ben Affleck did.

[Florida Today reporter Chris Kridler contributed to this article.]

Copyright 2002 FLORIDA TODAY.

=============
(6) COSMIC AIRBAG COULD SAVE THE PLANET

>From New Scientist, 29 August 2002
http://www.newscientist.com/news/news.jsp?id=ns99992730
 
Exclusive from New Scientist Print Edition
 
Airbags could one day save the planet. At least, that is the view of one
mathematician, who is suggesting that they could be used to nudge
asteroids or comets that are on a collision course with the Earth gently
out of harm's way.

All sorts of ideas for deflecting objects heading for Earth have been
touted since the comet Shoemaker-Levy 9 smashed into Jupiter in July
1994. These include detonating a nuclear bomb on their surface. But this
might not work: some asteroids are more like a pile of rubble than a
solid, and so would absorb the energy from a nuclear blast.

Computer simulations by Erik Asphaug of the University of California at
Santa Cruz suggest that a rubbly asteroid would absorb so much energy
from a nuclear blast that the explosion would have little effect on the
course of one of these "cosmic beanbags".

A blast would also risk splitting an asteroid or comet into dangerous
fragments that would still head for Earth.

It would be far better, says Hermann Burchard of Oklahoma State
University in Stillwater, to send spacecraft to fly alongside the
threatening object and inflate a giant bag some kilometres wide, using
gas produced by a chemical reaction. The spacecraft would then push the
bag against the asteroid.

This billowingspace pillow, Burchard argues, would distribute pressure
evenly over a large enough area to deflect the asteroid or comet gently,
but still keep it intact.

Rocket motor
 
Burchard thinks this should work for asteroids or comets up to 10
kilometres wide, providing the spacecraft carried enough fuel.

"It seems a safe, simple and realistic idea," he says. He admits,
though, that many questions have to be answered, such as what kind of
airbag material - Mylar, perhaps - would be tough enough for the job.

However, Asphaug thinks there's a simpler solution. "You probably can't
reliably use a nuclear explosion with predictable consequences," he
agrees. But he thinks that simply attaching a rocket motor - perhaps
with some kind of electric or even steam propulsion - to an asteroid or
comet would do the trick, without breaking it into fragments.

"Asteroids and comets are not so fragile that you can't touch them -
they get cratered all the time and don't fall apart," adds Asphaug. "So
you just need to apply gradual thrust over time. This can be done more
simply without bags of Mylar getting in your way."
 
Hazel Muir
 
Copyright Reed Business Information Ltd. 

===========
(7) WOULD GIANT AIR BAG STOP KILLER SPACE ROCK?

>From CNN, 31 August 2002
http://www.cnn.com/2002/TECH/space/08/30/asteroid.airbag/index.html

Would giant air bag stop killer space rock?
'It seems a safe, simple and realistic idea'
 
By Richard Stenger
CNN

(CNN) -- Some scientists have suggested nuclear bombs to deflect a big
comet or asteroid from a collision course with our planet. One
researcher has a more novel solution: a giant air bag.

An atomic detonation would do little to stop some types of asteroids,
which are little more than loose collections of rubble and would absorb
the energy without changing course, said Erik Asphaug of the University
of California, Santa Cruz.

In fact, his computer simulations indicate that such a blast could split
an incoming asteroid or comet into more fragments that remain on a
collision course.

Hermann Burchard of Oklahoma State University in Stillwater thinks a big
air bag could take care of such a cosmic "beanbag."

The mathematician proposes that a spacecraft could approach the object
and inflate a bag several kilometers wide using a chemical reaction to
make gas.

The probe would then push the bag against the incoming asteroid or
comet. The bag would distribute pressure evenly and nudge the object
away without fragmenting it, Burchard suggested.

"It seems a safe, simple and realistic idea," he told UK-based New
Scientist magazine. "Mylar, perhaps, would be tough enough for the job."


'My gut tells me to bet against this one'
Do other space scientists think the air bag idea is a good one or just
full of hot air? When asked via e-mail about the idea, Louis Friedman,
director of the Planetary Society, replied first with a smiley face.
Later he offered more.

"It seems impossible. The sheer scale of an air bag with sufficient
momentum to nudge a 5-kilometer solid rock hurtling around the solar
system at 100,000 miles an hour or so, is just beyond my comprehension,"
the former NASA rocket engineer said.

"Of course, on a long enough time-scale, like many centuries, I have no
idea what kind of engineering will be possible. But my gut tells me to
bet against this one."

Others received the idea with more enthusiasm.

"The basic idea makes sense. If a comet or asteroid is spotted with
enough advance warning, then a small nudge in the right direction will
change its course enough so that by the time it reaches Earth's vicinity
it will fly by without colliding," said NASA's Dave Williams.

"So the air bag isn't a crazy idea. It's definitely plausible, although
technically tricky, I'd imagine," said Williams, who works for the
agency's National Space Science Data Center in Greenbelt, Maryland.

Asphaug goes even further than Burchard in brainstorming methods to stop
killer space rocks. He likes the idea of avoiding nukes, but thinks the
job could be done, without air bags, without splitting the object into
more chunks, by placing a rocket engine on it and gradually thrusting it
away from a collision course.

Williams agrees: "Even rubble pile asteroids are not so fragile that
they need such gentle treatment, and what Eric Asphaug says is correct.
Rockets applied directly to the object, even without an air bag, would
probably serve to deflect it without causing it to break up."

2002 Cable News Network LP, LLLP.

============
(8) TEENAGER 'STRUCK BY METEORITE'

>From Ananova, 27 August 2002
http://www.ananova.com/news/story/sm_658058.html

A North Yorkshire teenager is convinced she has been hit by a meteorite
which could be billions of years old.

Siobhan Cowton says the small lump of warm rock fell from the sky over
Northallerton and landed on her foot.

She has compared it to pictures of meteorites on the internet and is
sending it for scientific analysis.

The 14-year-old said: "I thought it was a stone, but it looked very
unusual, with a bubbled surface and lots of tiny indentations - a bit
like volcanic lava."

Dr Benny Peiser, of Liverpool John Moores, University, says meteorites
fall to earth every day but the chance of being hit by one is rare.

He told the Daily Mail: "Sometimes people see things falling and it is
only ice from aircraft. A lot of terrestrial rock looks meteoric but
geologists or planetary scientists can analyse these things and tell
very quickly.

"If this is a meteorite it could be billions of years old and come from
the earliest formation of the solar system. There is speculation that
some may come from Mars."

The Cowton family is taking the piece of rock, which is about the size
of an adult's thumb, to Durham University to find out more about its
origins.

Copyright 2002, Ananova

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

(9) RE: "IMPACT AND THE END OF THE ROMAN EMPIRE IN THE WEST"

>From Mike Baillie <m.baillie@qub.ac.uk>

Benny,

I much enjoyed Ed's Essay on the possible multiple impacts in the sixth
century and his use of one of the miracles associated with Columba.  As
it is August, and the silly season, may I add a thought or two?

Columba is credited with "fore-seeing" a fall of sulphurous fire from
heaven.  Viz.

"Similarly at another time, on a day after the threshing of the grain,
Lugbe, of the family of mocu-Min, whom we have mentioned above, going to
the saint was unable to look upon his face, which was flushed with a
marvellous redness; and becoming greatly afraid he quickly fled away.
But the saint called him back by slight clapping of his hands.
Returning, he was at once asked  why he had run away so quickly, and he
made this reply: "I fled because I was much afraid."......"Then the saint
spoke thus: "In this hour, sulphurous flame has been poured down from
heaven upon a city of the Roman dominion within the borders of Italy;
and close upon three thousand men, not counting the number of women and
children, have perished.  And before the present year is ended, the
Gallic sailors arriving from the provinces of Gaul will tell you the
same."

Now what Ed didn't draw attention to was the name of the monk Lugbe.  Is
it a coincidence, I ask, that the name of the person being told of a
premonition of a fall of fire from heaven has as a main element the name
of the Celtic sky god Lug?  I ask this because previously I was struck
by the curious logic chain which went:
i) Tree-ring event at AD 540 (limits 536-545)
ii) Cause volcano? or comet?
iii) Arthur dies 537 or 539 or 542
iv) Arthurian cycle based of Celtic cycle involving CuChulainn and
Lug - two aspects of the Lug deity
v) Lug is described as "coming up in the west as bright as the sun
with a long arm i.e. a close comet
vi) So debate begins on whether the 540 event was due to a comet
vii) Now Ed brings in Columban "fire from heaven" story which just
happens to involve Lugbe.
viii) However, let us make another comparison.  The Columban story has
Lugbe "unable to look upon his face, which was flushed with a marvellous
redness"; other versions say things like "the saint's countenance shone
with such wonderful brilliancy..."

Now let us compare this with descriptions of Lug himself.  "The name
'Lug' derives from a Celtic root meaning 'light' and the god was
conceived as bright, youthful and glorious above all the other gods...and
like the setting sun was his countenance and his forehead; and they were
not able to look in his face from the greatness of his splendour...the
glory of his appearance was like that of the sun itself..."

Note that it is the setting sun with which he is being compared and
elsewhere this is used to suggest that there was a redness on Lug's
countenance. 

Does this sound like an accidental coincidence?  Of course it doesn't.
The people who recorded these stories (I prefer the term 'encoded') were
perfectly aware of what they were doing.  You are not meant to take them
literally, you have to look beyond the words given. 

ix ) what this story is telling us is that someone writing in the
seventh century was aware that fire from heaven was associated with the
sky god Lug, a comet.  So the story is dressed up as a miracle involving
a Christian saint.  This way the elements of the important story could
get past the 'censor'.  What are the elements?

Well, sometime in the sixth century (during the life of Columba 521-593
or whatever) sulphurous fire from heaven is related in some way to a god
or godly person who has the attributes and even the name of the Celtic
sky god Lug, whose description is consistent with a comet.  That is the
message the writer, the encoder, wished to preserve.

x)  Put simply the story is 'in the sixth century a comet rained down
sulphurous fire'.  Why did the writer not just say that?  Because in the
seventh century, when he was writing, it was not acceptable to have
comets raining down sulphurous fire.  Why?  Well as Hoyle and
Wickramasinghe said in Our Place in the Cosmos (1993) "By about the
sixth century AD, Christian beliefs included the dogma that nothing that
happens in the heavens could have any conceivable effect on the Earth."
QED, as they say.

Mike Baillie

==============
(10) AND FINALLY: ....... :-)

>From Northern Territory News, 31 August 2002

A BIG asteroid hit Earth, and blew it up, so everyone died and went to
heaven. When they got there, God came out and said: "I want all the men
to make two lines; one for the men who were dominated by their women,
and one for the men who dominated their women. Also, I want all the
women to go with St Peter."

So the next time God looked, all the women were gone, and the line of
men who were dominated by their women was 100km long. The line of men
who dominated their women had only one man in it.

God got angry and said: "Look at all of you shameful men who were taken
over by your women.

"I created you in my image but only one has stood up and made me proud.
Tell me, my son," he said to the one man who dominated his woman, "How
did you come to stand in that line?"

"I dunno," the man said. "My wife told me to stand here."

Luke Gray

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