CCNet 64/2001 - 4 May 2001

"Because they are surrounded by a cloud of their own gas and dust,
the nuclei of comets never reveal their exact size. Nuclei are frequently
estimated to be a few miles (or kilometers) in diameter, but only
after lengthy observations. So how big is C/2001 A2? "We have no
clue," Carl Hergenrother said. "It might be small. It might be big."
--Rob Britt,, 3 May 2001

"An impact this size on the Moon is predicted to happen once every
15 million years or so," Paul Withers told BBC News Online. "Having one
happen in the past 1,000 years would suggest that the predictions might
be dangerously incorrect and the Earth might be in more danger from
colliding space rocks than is currently thought." So a sigh of relief should
greet Withers' claim that, whatever those men saw that night, it was not the
creation of Giordano Bruno."
--Jo Kettlewell, BBC News Online 1 May 2001

"If there really is extraterrestrial intelligence somewhere beyond
our planet, it doesn't seem to be all that anxious to be discovered. For
decades now, scientists and ET enthusiasts have been keeping an ear open to
the heavens, expecting to pick up some clue, perhaps a television
program, or more likely a radio beacon used for interstellar navigation,
that would tell us he, she or it is out there. But so far, zilch. No
deliberate effort to contact us. No slip of the tongue that we might
overhear. Nothing. The latest disappointment comes from scientists who
suggest that if ET is out there, he may be having a tough time finding
a suitable abode. The research suggests there may be far fewer places out
there - planets like our Earth - that could harbor life than we had
--Lee Dye, ABC News, 3 May 2001


    Andrew Yee <>

    BBC News Online, 1 May 2001

    J. Mayo Greenberg <>

    ABC News, 3 May 2001

    Your Own World USA, April 2001

    Andrew Yee <>

    Alain Maury <>

    Mark Anderson <>

     New Scientist, 8 May 2001


From, 3 May 2001

By Robert Roy Britt
Senior Science Writer

What was at first a mundane comet zooming into the inner solar system
suddenly brightened unexpectedly this spring and was on the verge of putting
on a minor show by becoming visible to the naked eye.

Then it cracked under the pressure.

Carl Hergenrother, an astronomer at the University of Arizona's Lunar and
Planetary Laboratory, was conducting a routine sky survey on Monday with his
colleagues when he spotted a change in the comet, named C/2001 A2.

Like most comets, C/2001 A2 showed up in a telescope as just a bright spot,
which represents the core, or nucleus, of the object. When comets near the
Sun, a fuzzy halo grows around them as charged particles streaming out from
the solar disk burn off the frozen gases and dust in the core. Nearer the
Sun, tails form.

"Usually in the middle you just see one little fuzzy point source,"
Hergenrother said in a telephone interview on Wednesday. "And that's how it
looked when I shot it last week. But then on April looked a little

At first, the fuzzy core of the comet looked less like a point and more like
a bar.

"And then, upon getting some better images, I could break up that bar into
two separate little bright spots."

Hergenrother and his colleagues, graduate student Matt Chamberlain and his
wife Yen Chamberlain, reported their finding May 1 in a circular of the
International Astronomical Union.

Cracking under pressure

Because they are surrounded by a cloud of their own gas and dust, the nuclei
of comets never reveal their exact size. Nuclei are frequently estimated to
be a few miles (or kilometers) in diameter, but only after lengthy

So how big is C/2001 A2?

"We have no clue," Hergenrother said. "It might be small. It might be big."

And there's also no way to know how big each of the two new pieces are.
Sometimes the smaller parts produce more light depending on the composition
of each piece, Hergenrother said. The bit that broke off could be a big
boulder, or a small chunk of crust.

And though researchers aren't sure why a comet breaks up, it has to do with
the way they blow off steam. As a comet heats up, its ice "sublimates"
directly into gas, bypassing the liquid stage. This generates outward

"Kind of like a geyser like Old Faithful," Hergenrother explained, "the
pressure builds up and finally [a piece] pops off."

Naked-eye visible by June?

It's not unusual for comets to break apart. A spectacular example occurred
last summer when another comet, popularly called LINEAR, broke into several

(MIT's Lincoln Near Earth Asteroid Research telescope, or LINEAR, discovers
dozens of comets each year, generating some confusion in press reports over
which comet is which. C/2001 A2, the one that just broke apart, was also
discovered by LINEAR, in January of this year.)

Hergenrother says that while comet C/2001 A2 could also further break apart
any day, he does not expect that to happen, though the two pieces will tend
to drift apart as they continue to orbit the Sun.

The comet is currently visible through binoculars, though it takes a
high-powered telescope to see the double nucleus.

And first you have to find it.

It has been visible low on the horizon near the feet of the constellation
Orion, the Hunter. But the comet is heading into the Southern Hemisphere
skies and may no longer be visible from the United States, Hergenrother

It will come back into our Northern Hemisphere skies at the end of June
after it swings under the Sun. By then, it might be visible to the naked
eye, though that is not certain. And no one expects it to put on any kind of
show like Hale-Bopp or other popular comets past.

Sudden brightening

The brightness of stars and other celestial objects is measured on a scale
of apparent brightness. Smaller numbers are brighter and negative numbers
are the brightest. Magnitude 6.0 is the faintest object visible to the naked
eye under dark skies. The brightest star is minus 1.4 on the scale, and
Venus is minus 4.4 at its brightest.

Hergenrother and his colleagues have been watching this newly found comet
for months using a University of Arizona telescope. It was a typical, rather
mundane target that was not expected to brighten much.

"Then one day, all of a sudden -- whammo -- the thing got a hundred times

The jump in visual brightness occurred March 25-26, when it rose from an
indistinct magnitude 12 to 10.7. A few days later, it was near magnitude 8.
Then it faded slightly, but began brightening again over the past two weeks
and ultimately approached magnitude 6.

Copyright 2001,


From Andrew Yee <>

From The Guardian, 3 May 2001,3858,4179775,00.html

People expect meteorites to land in a blaze of heat, but they are in fact
icy cold, says Duncan Steel.

By Duncan Steel

Recently a woman walking her dog in York heard a whiz and a bang, and then
spotted a smoking hole in the ground. Assuming it was a meteorite impact,
the police cordoned off the area and a curator from the York Museum was
called in to dig up the supposed cosmic rock.

However, it was obvious, even from the sparse initial report, that this was
not a visitor from space. Meteorites are cold when they land, and generally
remain intact on the surface. It proved to be an exploding underground power

The chance of an extraterrestrial rock reaching the ground depends
critically on its dimensions, different things happening in distinct size
regimes. Every year the Earth accumulates about 40,000 tons of cosmic
detritus, mostly as billions of tiny flecks ranging in size from sand grains
to peas. Travelling at typically 20 miles per second, these are heated and
then evaporated by friction with the upper atmosphere, and in their death
throes they appear to us as meteors, or shooting stars.

Smaller particles -- less than a tenth of a millimetre in size -- decelerate
without being destroyed. This is possible because their relatively high
surface areas enable them to lose their energy by radiating it away, whereas
larger bodies cannot do this quickly enough, and so are melted and
vaporised. The small grains slow to a halt, and then gradually fall from
altitudes of some tens of miles until they reach the Earth's surface. Such
minute dust particles are termed micrometeorites.

This drop from altitude can take a surprisingly long time: years, in the
case of the tiniest interplanetary dust. Flying research jets in the
stratosphere, NASA scientists have collected samples by employing sticky
plates that project from the wings. Another way such cosmic dust has been
gathered for analysis is by melting and sieving large volumes of snow and
ice in the Antarctic and Greenland, where it has accumulated over millennia.

Actually, there are micrometeorites all around. In a typical house, about
one in a thousand dust particles on the mantlepiece may be of
extraterrestrial origin, depending of course on how often it is cleaned, and
how polluted your neighbourhood might be. A good repository of metallic
micrometeorites is the gutter on your roof, because they are gradually swept
down by the rain, and their high density makes them more likely to remain in
the sludge that builds up there.

Much larger meteoroids -- say between the size of an orange and a basketball
-- produce extremely bright meteors, called fireballs. These can light up
the night sky, producing daylight conditions for a second or two. Then the
object is gone, its atoms added to the atmosphere. In a small fraction of
cases, though, it is possible that some solid lump may reach the ground
intact. That is what we call a meteorite.

For it to survive in this way, the incoming lump needs to be lucky. First,
it is more likely to escape destruction if it is strong, made of metal or
solid rock as opposed to a loose, fragile structure.

Next, there is a greater chance of avoiding vaporisation if the object has
an entry speed close to the minimum possible: that is about seven miles per
second, identical with the Earth's escape velocity.

Finally, the survival probability of a meteoroid is much enhanced if it
happens to arrive at a fairly oblique angle. Under that circumstance it
decelerates slowly, over a prolonged period rather than just a couple of
seconds. The same applies to re-entering space probes such as the Shuttle,
or the Apollo lunar capsules. Come in at too steep an angle and you burn up;
but if the approach is too shallow, you bounce off the top of the atmosphere
like a flat stone skimmed across a pond.

Meteorites, then, are rare. But what is their temperature? Arriving on a
suitable trajectory, they are slowed from their phenomenal cosmic velocity
to essentially zero in 10 or 20 seconds. As they do so, their outer layers
are intensely heated, and ablate away. The melted exterior of a meteorite,
called a fusion crust, is obvious. But the interior is unchanged. During its
fiery plunge there is simply not enough time for the heat to be conducted
into its centre.

As a result, when meteorites reach the ground their interiors are still at
the temperature they had in space, around minus 30C. If the Earth had no
atmosphere, that would be the planet's temperature at our distance from the
Sun. It is only the natural greenhouse effect that gives our home its
pleasing ambient temperature. (The scientific debate over global warming
concerns whether manmade emissions are enhancing the greenhouse effect by a
small but significant proportion.)

One can think of the effect of atmospheric entry on a meteorite as being
similar to throwing a deep-frozen joint of meat into a fire. Five minutes
later the outside may be charred, but the middle is still icy.

Just-fallen meteorites, then, are cold. It is not unusual for an observed
fall, someone reaching the object within a few minutes, to produce a report
of ice on its exterior. Water vapour in the air first condenses on to the
meteorite and then freezes.

Do meteorites make craters? The multitude of scars on the Moon is obvious,
but there are also about 250 recognised impact craters on the Earth. The
best known is Meteor Crater in Arizona. That massive hole, 1,300 yards
across, was formed 49,000 years ago when a nickel-iron projectile about 40
yards in size slammed into the ground, releasing on impact energy equivalent
to about 20 megatons of TNT. The atmosphere does not brake such a body by

Little boulders from space are different, though. The atmosphere slows them
down in one way or another. They are either totally destroyed, or else
brought to a halt. An orange-sized rock would be decelerated by the time it
reaches a height of 20 miles. From there it gets to the ground
under free fall: it plummets at the same rate as an object dropped from a
plane, reaching a terminal velocity of about 200mph.

Compared to the hypervelocity impact of a very large body like an asteroid
or a comet, that is a low speed. As a result, small meteorites do not form
craters. If one were to land on soft ground, it might bury itself a bit, but
that is all. In 1947 a large metallic body broke up on atmospheric entry
over the east of Siberia, and many of the fragments weighing over a ton
managed to penetrate the earth by a metre or so. The 60-ton meteorite that
landed in Namibia in prehistoric times -- the largest known intact meteorite
-- sits on the surface, although it did cause a bit of a dent.

If you should hear a loud bang and find a smoking crater, suspect that
someone has been playing with dynamite. To excavate an impact crater a
projectile from space has got to be large, and would make a hole far too big
for the police to cordon off. Mind you, they would have other things to
worry about.

[Duncan Steel works at the University of Salford. His most recent book is
Target Earth, published by Time-Life.]

© Guardian Newspapers Limited 2001


From the BBC News Online, 1 May 2001

Did a space rock carve one of the biggest Moon craters?

By BBC News Online's Jo Kettlewell

On a clear midsummer night in AD 1178, five men gazing at the sky witnessed
something astonishing; a mystery which remains unsolved. Stunned, they
watched as the Moon began to spew out fire and sparks, and writhe as if in
pain. Several times it did this, before taking on a blackish appearance.

The events of that night are recorded in the medieval chronicles of Gervase
of Canterbury, and they have puzzled historians and scientists alike for
most of a millennium. What could possibly explain this deeply strange

The most widely accepted theory is that the five men witnessed a huge
meteoroid hitting the surface of the Moon; an impact so big it could have
wiped out civilisation, had it occurred on our planet. It is said that this
impact could have created the 22-kilometre- (14-mile-) diameter lunar crater
Giordano Bruno.

But, according to a US researcher, this theory does not quite add up. Paul
Withers, a graduate student at the University of Arizona, suggests in this
month's issue of Meteoritics and Planetary Science that a collision this big
would have resulted in millions of tonnes of moon rock showering down to
Earth. There is no record of such a shower ever taking place.

'Flaming torch'

It was about an hour after sunset on June 18, AD 1178, that the group of
five eyewitnesses saw the upper horn of the bright, new crescent Moon
"suddenly split in two. From the midpoint of this division a flaming torch
sprang up, spewing out... fire, hot coals and sparks... The body of the
Moon, which was below writhed... throbbed like a wounded snake".

A geologist suggested in 1978 that this dramatic passage from the chronicles
of Gervase of Canterbury might be an account of the formation of the
Giordano Bruno lunar crater. Giordano Bruno is in a position that could be
consistent with this description; it is also the youngest crater of its size
or larger on the Moon, meaning 1178 could conceivably be its birth date.

Giordano Bruno was made when an asteroid almost three kilometres (two miles)
wide slammed into the surface of the Moon. Had it hit Earth, it is likely
that none of us would be here today.

"An impact this size on the Moon is predicted to happen once every 15
million years or so," Paul Withers told BBC News Online. "Having one happen
in the past 1,000 years would suggest that the predictions might be
dangerously incorrect and the Earth might be in more danger from colliding
space rocks than is currently thought."

So a sigh of relief should greet Withers' claim that, whatever those men saw
that night, it was not the creation of Giordano Bruno.

Meteor storm

An asteroid impact that size on the Moon would have catapulted 10 million
tonnes of debris into the Earth's atmosphere, Withers said, causing an
impressive meteor storm.

"I calculate that this would cause a week-long meteor storm comparable to
the peak of the 1966 Leonids," he said. "They would be very bright, very
easy to see. It would have been a spectacular sight! Everyone around the
world would have had the opportunity to see the best fireworks show in

But no-one ever reported this firework extravaganza. Historical records show
nothing, including the European, Chinese, Arabic, Japanese and Korean
astronomical archives.

Paul Withers thinks the witnesses might have seen a small meteor that was
directly in front of the Moon coming straight towards them through the
Earth's atmosphere, as they looked up at the sky that night. Perhaps they
did, but we cannot be sure. The events of June 18, 1178, remain a
tantalising mystery.

Copyright 2001, BBC

From J. Mayo Greenberg <>

Dear Benny,
It would be of interest to your readers in your newsletter the website for
the meeting on "The Physical Properties of Potential Earth Impactors: KNOW

I also think it would be of interest to include the Purpose of the

The main objectives of the course are to learn what we know now and what and
how we can learn more about the physical and chemical properties of
potential earth impactors; namely, asteroids and comets, with the ultimate
aim of providing the best possible data for mitigation procedures. A major
concern to the world is the potential devastation produced by impacts of
cosmic objects from space For this reason we consider as a subtitle for the
school: 'KNOW YOUR ENEMY'. The lectures will be devoted to consideration of
all possible means  from theoretical to experimental to remote observational
to space observational, to space in situ measurements  for obtaining the
internal structure and composition of asteroids and comets. The course will
include a series of workshops which will summarize and supplement the
lectures and provide suggestions for further studies in the application of
all techniques which can be used to provide a data base on cosmic object
properties. A significant consequence of the course will be its application
to knowledge of the formation of the Solar System. This course, as was the
case for all the previous ones in the Space Chemistry School, is highly
interdisciplinary, bringing together experts with a wide variety of
chemical, physical and technical backgrounds in theory, laboratory
astrophysics, ground based observations and space observations as well as


From ABC News, 3 May 2001

Fewer Planets, Less Life?
Fragile Status of Young Planets Suggest ET is Unlikely

By Lee Dye
Special to

May 3 - It's hard not to hope that ET is out there somewhere, waiting for us
to discover clear evidence that we are not alone in the universe, but the
news these days is a bit discouraging.
If there really is extraterrestrial intelligence somewhere beyond our
planet, it doesn't seem to be all that anxious to be discovered. For decades
now, scientists and ET enthusiasts have been keeping an ear open to the
heavens, expecting to pick up some clue, perhaps a television program, or
more likely a radio beacon used for interstellar navigation, that would tell
us he, she or it is out there.

But so far, zilch. No deliberate effort to contact us. No slip of the tongue
that we might overhear. Nothing.

The latest disappointment comes from scientists who suggest that if ET is
out there, he may be having a tough time finding a suitable abode. The
research suggests there may be far fewer places out there - planets like our
Earth - that could harbor life than we had thought. If that's right, then
legions of scientists have erred in telling us for years now that other
planetary systems are probably common. And the odds of life existing
elsewhere have taken a big hit.

'Planet Stoppers' Keep Numbers Down

These ideas tend to come and go with the rise and fall of tidal waves of
information brought to us by such marvels as the Hubble Space Telescope, but
over at Vanderbilt University, they are calling the latest finding a "planet
stopper." That's tough talk indeed.

It turns out that "stellar nurseries" where new stars are formed are so
violent that the dust needed to build planets may be blown away before
planets can be formed. Only those new stars shielded from powerful
interstellar winds by distance or other bodies would have a chance to form

That means only about one star out of 10 would have any chance of forming a
planetary system, according to C. Robert O'Dell, a research professor at
Vanderbilt who has spent nearly 40 years studying that most famous of all
stellar nurseries, the Orion Nebula.

Here's what many scientists thought was going on:

The Orion Nebula, located about 1,500 light years from Earth, is rich with
interstellar clouds of molecular gas. The gas gradually coalesces into new
stars in a dramatic process that has long fascinated astronomers. In recent
years astronomers have been able to detect rings of dust around some young
stars, most notably the nearby star of Beta Pictoris, leading many to
conclude that dust left over from star formation routinely forms a flattened
disk around the star.

The dust in the disk should gradually coalesce into planets, and it was
thought that was a common scenario.

Indeed, when the Hubble was turned toward the Orion Nebula for the first
time in 1993, it produced images that indicated that up to 90 percent of the
young stars in the nebula were surrounded by "protoplanetary disks,"
according to O'Dell. That gave great support to the notion that most stars
had what it took to build planets.

Dust-Busting Bullies

But when O'Dell and several other scientists took another look at the data,
they discovered something quite surprising. The heart of the "stellar
nursery" has a number of very young, massive stars that are 100,000 times
more luminous than the sun.

These are not the kind of stars you want to trust with your newborn. They
are so violent that they send off waves of ultraviolet radiation that should
blast the dust to smithereens in a few hundred thousand years, O'Dell told
the American Physical Society in Washington this week.

Most experts think it takes at least 10 million years for new planets to
form, and therein lies the problem. Before the planets can form, the
protoplanetary disk will be wiped out by the hot breath from neighboring big

"It appears that most of the disks will be gone long before planets can
form," O'Dell says.

The finding fits neatly with other recent research on the Orion Nebula. A
team led by scientists at the University of Colorado at Boulder used the
Hubble to study dust particles in the nebula. The researchers found evidence
of dusty disks surrounding several young stars similar to our sun, and the
dust appears to be clumping together in what would be the first stage of
planetary formation.

But like their colleagues at Vanderbilt, the Colorado researchers also found
the "nursery" so violent that "it's a hard place to raise a family of
planets," says researcher Henry Throop.

The problem, once again, is massive stars that blast their neighbors.

"UV [ultraviolet] light comes streaming off these large stars like a
blowtorch, evaporating the gases and removing the dust from the
circumstellar dust rings of the smaller stars," Troop says.

Lonely Universe?

That appears to eliminate any chance that most of the stars will form
planets, but on the other hand, some stars that were farther away from the
bullies seem to be doing quite well. So some of the stars should be able to
produce planets, just not nearly as many as had been thought.

So it doesn't mean there aren't any more planets out there like Earth. We
know planets can form, because it happened here. But if the latest research
withstands the test of time, it may turn out that stars with planets are the

And the universe could be a lot lonelier than we might like.

Lee Dye's column appears weekly on A former science writer for
the Los Angeles Times, he now lives in Juneau, Alaska.
Copyright 2001, ABC News


From Your Own World USA, April 2001

Citizen Request For A Congressional Hearing To Re-Evaluate The Goals Set
Forth In The NASA Multiyear Authorization Act Of 1990, With Specific Regard
To The Possibility That An Impact Event Could Precipitate A Nuclear Exchange
By Third World Countries

Congressman Rohrabacher, Chairman
Space and Aeronautics Subcommittee

Washington, D.C. Office
2338 Rayburn House Office Building
Washington, DC 20515
(202) 225-2415

District Office
101 Main Street, Suite 3C
Huntington Beach, CA 92648
(714) 960-6483

Marshall Masters, Publisher

Dear Congressman Rohrabacher:

I am writing to you as the Chairman of the Space and Aeronautics
Subcommittee because our government, and NASA in particular, has virtually
ignored the threat of a nuclear exchange precipitated by a Tunguska-class
meteorite impact in the near vicinity of a nuclear-capable third world

Congress initially acted on the need to discover potential impactors in
1990, and clearly identified the possibility of an impact event as being a
genuine threat to the country.  

"The Committee believes that it is imperative that the detection rate of
Earth-orbit-crossing asteroids must be increased substantially, and that the
means to destroy or alter the orbits of asteroids when they threaten
collision should be defined and agreed upon internationally..."   
NASA Multiyear Authorization Act of 1990

At the time when the NASA Multiyear Authorization Act of 1990 was voted in,
the world faced the threat of a nuclear exchange between America and the
Soviet Union. Since then, the Soviet Union has collapsed and nuclear-capable
third world nations, such as Pakistan and India, are separated from their
neighbors by ancient ethnic hatred. Further, other nations including Iraq
and North Korea, are also suspected of being (or will soon be)

Since then a great deal has changed and what was a scientific hazard in
1990, has become a national defense issue with the highest possible
priority. Simply put, for the price of one EP-3 surveillance airplane, our
nation could do far more to prevent a possible nuclear exchange by
reassessing and improving our existing Earth-orbit-crossing asteroid
detection capabilities.

My reason for bringing this to your attention is your proven track record
for supporting the defense of our country from the threats posed to us by
emerging nuclear-capable nations, and your forward thinking position on the
commercialization of space.  I especially appreciate your support of
reusable launch vehicles such as the DC-X Single Stage Rocket Technology

How a Nuclear Confrontation Might Be Triggered

Major nuclear powers like America and Russia spend tremendous sums of money
on systems designed to identify the difference between an incoming ICBM and
an incoming meteorite, but what about nuclear-capable third world countries
like Pakistan or India?  But more importantly, what about those countries
that share nuclear and/or missile technology with states that are openly
hostile towards America.  

In your Special Orders Speech on September 17, 1999, you stated:

"Let me make this very clear. The Clinton policy of treating Communist China
as a friend, as a benevolent country, as a strategic partner, has resulted
in putting the United States in grave danger."

While China apologists would be quick to dismiss your position, there are
many others who agree fully with you. Further, there is no doubt in many of
those minds that China has illegally exported nuclear technology stolen from
the United States to rogue nations that have demonstrated an open hatred of
America and its allies. Consequently, the possibility that countries like
North Korea and Iraq may already posses a small arsenal of nuclear warheads
along with the means to deliver those warheads cannot be ignored. 

Given the heightened tensions in the Middle East, the following news story
goes straight to the heart of the matter. 

AFP, April 23, 2001
Meteorite crashes near mourning Jordanian village

AMMAN JORDAN -- Residents of a Jordanian village attending a funeral
got an unwelcome surprise when a fiery meteorite crashed down in
their midst, one of them told AFP Monday.

"More than 100 of us were gathered Wednesday at sundown to bury a
village resident when we saw a strange object that looked like a ball
of fire," said Mohammed Nawaf Mikdadi, mayor of Beit Eidess, some 85
kilometers (50 miles) north of Amman.

"The meteor shot through the sky from west to east before a part of
it came down a half kilometer (quarter mile) from the village, sparking
an explosion and then a fire with four- meter (12-foot) flames for 10 meters
(100 feet) straight," Mikdadi told AFP.

"The villagers thought it was a missile, but when we went to the
spot there weren't any metal scraps," he said.

The mayor expressed relief the meteorite fell on a rocky area near
Beit Eidess and not in a nearby forest, which could have spelled
disaster for the village.

Congressman Rohrabacher, the key words here are "THE VILLAGERS THOUGHT IT
WAS A MISSILE."  Imagine what could have happened if the meteorite been
large enough to impact with a yield similar to that of a small tactical
nuclear warhead. 

Historical Perspective

With the NASA Multiyear Authorization Act of 1990, Congress specifically
instructed NASA to implement an Earth-orbit-crossing asteroid detection
program. However, the act did not include a specific allocation of funds to
accompany this mandate.   

At that time, NASA consulted with top astronomers in the field and was
advised that the task would require several 3-meter telescopes, which would
enable them to detect objects as small as 200 meters in diameter. 

Given that it had a mandate without a specified budget, NASA opted to use an
existing 1-meter model that was old but still operable. This largely
explains why NASA focused its efforts on the detection of asteroids 1 Km in
diameter or larger, as this is essentially the best you can do with a
1-meter telescope. Besides, in 1990 the threat of Earth-orbit-crossing
asteroid was primarily a scientific issue. After all, who has ever lived to
see anyone die as the result of an impact event? 

Consequently, NASA chose a scaled down approach that was financially
palatable even though it completely negated the thoughtful recommendations
of leading astronomers of that time. 

However, the world scene has changed dramatically since then and the time
has come to reevaluate our NEO detection efforts since 1990.

The Current Situation

Faced with a shrinking budget, the financial burden of the International
Space Station and the shuttle program, NASA has been hard pressed to
allocate additional resources to this task in the intervening years. While
it has announced an aggressive time schedule for identifying 90% of all
potential impactors that are 1 Km in diameter or larger, the announcement is
viewed with as much skepticism in the scientific community as a Soviet era
5-year plan, and rightly so. Simply put, NASA is hoping for champagne on a
beer budget. 

Funding is on a shoestring, and a typical sized fast food restaurant has a
bigger head count than the total combined numbers of those paid by our
government to search the skies for potential impactors. This has not changed
much since 1990, except that the number of NEO observers on the payroll now
equals that of a fast food restaurant plus a handful of curbside hot dog

Nonetheless, the moment the media begins to smell an asteroid story, they
immediately pick up the phone and call NASA. "What do you know about this
rock?" they ask, expecting a definitive statement. Since the NEO detection
effort is so understaffed, reporters often catch NASA off-guard and
flat-footed when they call. 

If NASA were to answer with something completely honest like "Golly gee,
that's a new one to us. Boy, you sure caught us by surprise," they know
someone would be sure to use that answer as a way to carve a thick slice off
their next funding request. 

What keeps things afloat is largely the result of superhuman contributions
by overworked, dedicated astronomers. But, a handful of people consistently
working 60 - 80-hour weeks cannot compensate for the overall lack of
financial support a program this important truly requires. 

Because these publicly funded astronomers are limited by the use of a
1-meter telescope, they essentially competing with the independent and
amateur astronomers for the same kinds of sightings. Consequently, we're
becoming very good at finding large impactors which have a very slight
statistical likelihood of impacting the Earth, along with asteroids that
parked in very regular orbits between Mars and Jupiter. Meanwhile, the money
simply is not there for the detection of the smaller 50-150 meter
Tunguska-class impactors that are far more likely to strike the Earth with a
great loss of life.  

An Artificial Fixation on Size

Old notions are often slow to die, and the notion that potential impactors
that present a real harm to us must be larger than 1 Km in diameter is an
accountant's view of reality, and represents a skewed and self-defeating
fixation on size. 

Since congress passed the NASA Multiyear Authorization Act of 1990, a myopic
fixation on impactors that are 1 Km in diameter or larger has remained, in
spite of the fact we now possess the technology to find Tunguska-class
impactors with a great deal of reliability.  

Still the same, the whole issue of impactor size seems to dominate the
thinking that surrounds the threat of an impact event. As the thinking goes,
the bigger the impactor, the greater the destruction. However, this is not
always so. 

While size is the key factor used to estimate the destructive force of a
potential impactor, there are also host of related factors that when taken
together as an aggregate are just as important as the issue of size, if not
more so.  

In general terms, these non-size factors include:

Speed and Angle of Attack:  Important in terms of the atmosphere
Composition: Stony rock, iron, silicates, etc.
Type of Impact: Airburst, ground hit, water hit
Impact Area: Inland areas, ocean, coastal areas
Approach Path: Dispersion of initial impact blast forces and debris

Therefore, when comparing two impactors of different size, these non-size
factors can offset the difference in size, and enable a relatively small
impactor to yield the same destructive force as a larger one.

To illustrate this point, let's compare two different impactors from the
opposite sides of the same object size scale. On the humongous side of our
size scale, we'll use the 6-mile wide impactor that wiped out the dinosaurs
65 million years ago as our example.  

On the tiny side of the size scale, we'll use the pea-sized .22 caliber
bullet John Hinckley fired into President Reagan's chest that nearly ended
his life.

Humongous Impactor Example

Many scientists believe that there were at least three "Great Extinction"
due to impact events, dating back to 305, 205 and 65 million years ago. The
most widely known of these was the Chicxulub impact on the Yucatan peninsula
in Mexico (bordering the Gulf of Mexico) 65 million years ago, which
resulted in the extinction of the dinosaurs. 

Oddly enough, had the 6-mile wide Chicxulub impacted the Atlantic Ocean at
one of its deepest points, mankind might not exist today, or exist as we've
come to know ourselves. This is because the Chicxulub hit in one of the
worst imaginable places on Earth. 

The ground area it struck was layered with calcium carbonate (limestone) and
calcium sulfate (anhydrite), and the asteroid hit this ground with a speed
20 times greater than that of a high-powered rifle bullet.  

When limestone and anhydrite are heated under the extreme temperatures of
high-speed impact, the net result is a huge and sudden increase in
greenhouse gases just like the carbon dioxide that spews out of our car
exhausts and factory smokestacks. Consequently, the Earth became
insufferably hot for centuries. In essence, the Chicxulub asteroid was a
6-mile wide Golden BB.

Fighter pilots coined the term "Golden BB", and it describes what can happen
when a small caliber bullet strikes a highly vulnerable part of their
airplane. It causes a catastrophic event and the pilot usually dies.

While the Chicxulub impactor was no BB in terms of size, the fact that it
just happened to strike a thick layer of limestone and anhydrite at high
speed could certainly be considered a "Golden BB" effect. 

In present day terms, imagine what would happen if a small, solid iron
meteorite big enough to make a crater the size of a soccer field were to
strike the Chernobyl nuclear power plant in the Ukraine dead on and at high
speed, as opposed to striking a hundred miles to either side of it.  The
difference between a worldwide disaster and a regional disaster in this
case, would be the "Golden BB" effect. 

Simply put, the size of an impactor is also subject to the three most
important aspects one must consider when acquiring commercial business real
estate: Location, location and location.

Pea-Sized Impactor Example

One any given clear night, you can see shooting stars crossing the heavens.
These are mostly pea-sized asteroids. Likewise, the bullet John Hinckley
shot into Ronald Reagan in March 30, 1981 was from a .22 caliber pistol,
which happens to shoot a pea-sized bullet.

Having lost a considerable amount of blood, the grievous wound caused by his
pea-sized bullet would have killed most men of President Reagan's age.
Thanks to the skilled physicians at George Washington University Hospital,
the bullet was removed from his left lung and President Reagan survived -
but barely.

Many of those who own a .22 pistol, typically use it for recreational target
shooting on a supervised range, or for plinking tin cans outside of town.
For these folk, the amount of bodily damage and blood loss suffered by
President Reagan seemed unusually excessive. They wondered how could a .22
do that much internal damage? For many, it just did not make sense.

However, what most did not know is that John Hinckley did not use the same
common .22 caliber ammunition commonly found at your local Walmart or K-Mart
for target practice and plinking. Rather, he carefully searched the market
for the "Devastator" brand, which is the most lethal.22 ammunition, made,
and is often referred to as "cop killer" ammunition.   

What makes this particular ammunition so deadly is that the bullets have
lead azide-filled centers within lacquer-sealed aluminum tips. On impact,
the bullet expands grossly and then explodes inside the victim's body. These
bullets are designed to inflict maximum soft tissue damage.

Devastator ammunition is not a general retail item, and is difficult to find
unless you know exactly what you're looking for. Therefore, selecting this
kind of ammunition is most certainly a sane and premeditated act.
Nonetheless, a jury found Hinckley "NOT GUILTY BY REASON OF INSANITY" 1982,
and the resulting public backlash kicked the teeth out of this commonly used
defense strategy. 

The point here is that while the bullet was basically as big as a pea-size
shooting star, its composition made if far more deadly than another other
comparable bullet of its size and in certain respects, almost as powerful as
the 9mm bullets now used as standard issue by police all around the world. 

Smaller Impactors Kill Too

In this case, the size of an impactor and its destructive force is relative
to its composition.  In the case of asteroids, there is a whole range of
compositions such as the stony asteroids that are as common in the universe
as the .22 plinking ammunition you'd buy at a general retail outlet like a
Walmart or a K-Mart. And then there are the solid iron asteroids that are as
lethal as a Devastator bullet, and equally difficult to find.  

So the question of size boils down to what is going to hit you, a
garden-variety plinking bullet or a lethal Devastator bullet, and your
willingness to assume that the universe is so merciful that it would never
use a Devastator against anyone.  

All of this goes to prove one simple point, that size is only one of several
factors that will eventually determine the destructive force of an impact

Yes, the big impactors do kill, but so do little ones. Therefore, we need to
find as many of them as we can without an arbitrary size bias based on an
anachronistic accounting decision.    

Tunguska-class Impactors -- A Clear and Present Danger

Since 1990, NASA has focused on impactors commonly known Extinction Level
Event (E.L.E.) objects such as the one that ended the reign of the dinosaurs
65 million years ago, thanks to popular movies such as Deep Impact.  

However, these E.L.E. impact events happen in periods measured in the
millions of years, whereas the impactors that are likely to strike in our
lifetime do so in span of time measured in terms of decades.    

In the last century, Tunguska-class impact events happened during the Solar
Maximums of 1908 in Tunguska, Siberia and in the Northern Amazon in 1930.
The Tunguska meteorite was approximately 50 meters in diameter, and its
impact released a destructive force comparable to 1,300 Hiroshima bombs. 

The impactor that hit the Amazon impact created fires in the rain forests
that persisted for months according to the Catholic Priest who witnessed the

The key points to remember about these Tunguska-class impact events, is that
each occurred during a Solar Maximum, and that impact events of this
magnitude happen every 50-100 years. 

We need to be concerned about this, because on February 15, 2001, NASA
announced that our Sun had finally reached the peak of its current Solar
Maximum and that this is the most violent Solar Maximum in recorded history.

Just recently, a solar flare occurred that literally went off the scale
forcing the creation of whole new category for solar flares. Meanwhile,
we're seeing unusual behavior with comets like S4 LINEAR that suddenly
disintegrated last summer, and A2 LINEAR, which began exhibiting unusual
behaviors earlier this month. 

NASA/JPL, April 20, 2001
C/2001 A2 (LINEAR) Brightens Unexpectedly

C/2001 A2 (LINEAR) has brightened significantly.  It is now clear
that this is not an outburst in the classic sense.  If it was, the comet
would have faded by now

Sometimes warning signs come in small and obscure forms. On December 7, 1941
the Officer of the Day chose to ignore the report of massive incoming
flights of airplanes received from a newly installed radar site serving
Pearl Harbor, HI. 

Congressman Rohrabacher, will it take Tunguska-class Pearl Harbor to get the
attention of Congress?

Small blips are turning up again. This time they represent the danger of a
nuclear war precipitated by Tunguska-class impact event and we're not even
looking for them.

We Have The Technology

Since the NASA Multiyear Authorization Act of 1990, the technology needed to
detect small Tunguska-class has come of age. It is sitting on the shelf,
proven and available for immediate use now. Yet, it is gathering dust as
political decisions backfill the new realities of the 21st century. 

Faced with a cash crunch on one side, and a sometimes-reckless media on the
other, NASA implemented a 72-hour suppression policy in 1998 to help them
control the media spin.  

There are several scientific reasons why this policy is an outright danger,
but since those have been summarily ignored let's examine the political
reasons as to why this is a dangerous policy. 

For starters, this is setting the government up for another Roswell type of
conspiracy scandal. Given that nobody (human) died in the Roswell incident,
should this 72-hour suppression policy become associated with a loss of life
it would be a catastrophic publicity failure for our government. Further,
suppressing information like this is not very encouraging to foreign

Keep in mind that one of the principal reasons why China refused to sign the
Nuclear Test Ban treaty was the issue of how the treaty would degrade their
ability to deal with a potential impactor. The NEO suppression policy
currently practiced by NASA only lends additional weight to that argument.

The world has changed, and 90's-era political thinking is not the solution,
and throttling the efforts of a few overworked astronomers by imposing
external control mechanisms designed for politically minded "controlling
authorities" is a dangerous way to compensate for a lack of adequate
financial support.  

What we need is to recognize that this process should be returned to its
organic and free pre-1998 state, and that the need to contribute additional
resources to this vital effort is urgent.  

The Judgment of History

Given your congressional record on this matter, there is no doubt in my mind
that you both sympathetic and concerned. However, the real difficulty might
come from those members of congress who do not share a similar concern. 

God forbid the worst should happen, and a Tunguska-class impact event does
precipitate a nuclear war. Americans will suffer. Whether it comes in the
form of direct strikes or from what the winds bring our way we will bury our
children in mass graves.  

However, what about our leaders in Congress? When they and their families
emerge from the bunkers built with taxpayer dollars, they will have to face
those who survive and their questions. 

As things stand, every member of Congress would have to watch as ambitious
young bean counters comb through their voting records looking for less
worthy pork barrel projects used to grease the wheels of legislation. 

Yet, for the price of a single EP-3 surveillance airplane, every member of
Congress could look America in the eye and say, we did everything humanly
possible with technology available to us.  

But, that would be too expensive. Wouldn't it?

A primary argument against expanding the NEO search to Tunguska-class
objects is that there are literally millions of them in our solar system,
and the cost of identifying and tracking them as potential threats would not
be cost effective.  

Regrettably, if the FBI were running the NEO problem the whole situation
would be different.  This is because the FBI uses a program called Carnivore
to indiscriminately and routinely sniff the millions upon millions of
e-mails Americans send to each other each day.  

Carnivore can automatically identify any individual that posses a potential
threat and then flag them for continued observation. It is the consummate
threat detection system.   

So, if we can cost justify Carnivore to locate threatening people, why is it
we cannot justify the cost of locating Tunguska-class impactors? Is it
because space rocks are not as deadly as schoolteachers?    

Immediate Action is Needed

As the Chairman of the Space and Aeronautics Subcommittee, I implore you to
schedule hearings on this matter as soon as possible for the benefit of all
concerned citizens. 

The goal of these hearings should not be finger pointing. This need is
simply too great for counterproductive pettiness of politics. 

Rather, we must come together to look at how the world has changed since the
NASA Multiyear Authorization Act of 1990, and to realize that in the
intervening years that this need has escalated from that of a purely
scientific venture, to one that now represents an urgent national defense

Respectfully submitted
Marshall Masters, Publisher


From Andrew Yee <>

University Communications
University of Wisconsin-Madison


Climate shift linked to rise of Himalayas, Tibetan Plateau
By Terry Devitt,

By probing ancient dust deposits in China and deep ocean sediments from the
North Pacific and Indian Oceans, scientists have constructed the most
detailed portrait to date of the effects on climate of the Himalaya
Mountains and the great Tibetan Plateau.

The picture that is emerging, drawn with the help of newly analyze geologic
records and a sophisticated computer-driven climate model, portrays the rise
of the towering Himalayas and the adjacent Tibetan Plateau, the world's
largest, as the primary driver of the onset of Asian
monsoons about 8 million years ago, and hints that the rise of the world's
tallest mountains and plateau may also have helped set the stage for the Ice
Ages that began about 2.5 million years ago.

An international team of scientists from China and the United States now has
documented the profound influence the Himalaya-Tibetan Plateau has on
climate over a broad swath of the world.

"The work further defines the effects of mountain and plateau uplift on
climate change," says John E. Kutzbach, a climatologist at the Center for
Climatic Research and a co-author of the paper published in the May 3
edition of Nature by An Zhisheng of the Chinese Academy of Sciences,
lead author, and Warren L. Prell of Brown University and Stephen C. Porter
of the University of Washington.

In 1989, Kutzbach, Prell, and Columbia University's William R. Ruddiman were
among the first to suggest that the uplift of mountains and large plateaus
could significantly affect climate.
In recent years, geologists have developed tectonic models of how, over the
past 10 million years, the Tibetan Plateau has risen as much as two miles as
the Indian subcontinent has continued to plow into Asia. To assess the
effects of the rise of the Himalayas and the Tibetan Plateau on climate, the
team used a computer model of world climate to show that the mountain and
plateau uplift enhanced both the winter and summer Asian monsoons and gave
rise to a drying trend in central Asia.

This drying trend may have helped create the Gobi and Mongolian deserts and
caused a very fine dust to be carried on prevailing westerly winds from the
deserts east to China and beyond where it left a record in both land and
ocean sediments.

In western China, the fine-grained particles of dust collected in huge loess
deposits providing a record of climate that can be read "like the pages of a
book. You can dig down into these deposits and read the story of past
climate, " says Kutzbach. "The base of these loess sediments has now been
dated to eight million years ago, thereby providing evidence of the timing
of uplift that is independent of that obtained from tectonic models."

The Chinese loess deposits, together with the records from Indian Ocean
sediments that indicate onset of the Indian summer monsoon at about the same
time, provide physical evidence that is consistent with the computer model's
picture of the evolution of Asia's climate.

For eight million years, the Himalayas have trapped and diverted
precipitation to the south and east of the Tibetan Plateau, preventing
moisture from reaching what are now the Mongolian and Gobi deserts.

"The uplift of the mountains has diverse regional effects," says Kutzbach.
"It's drier in some regions and wetter in others, giving us a satisfactory
explanation of why there are large Asian monsoons and why some areas are

Moreover, climate signals found in the Chinese loess deposits suggest that
between 3.6 and 2.6 million years ago dust deposition increased, suggesting
that the winter monsoons of eastern Asia intensified. This further climate
transition, perhaps caused by continued uplift of the Tibetan Plateau along
its northern and eastern margins, "signaled a dustier phase in the Earth's
atmosphere," Kutzbach says, "and, at the same time, glacial cycles

It is possible, Kutzbach says, that other factors led to the intensification
of glacial cycles and, in turn, increased polar aridity, increased intensity
of earth-scouring winds, and a dustier atmosphere.

"It's the chicken and the egg scenario. We don't know what came first, but
it is possible that the continued uplift of the Tibetan Plateau at its
northern and eastern margins may have helped set the stage for the
transition to a colder climate with more intense glacial cycles."

Dust storms, such as the one reflected in the satellite image of dust blown
into the atmosphere over Asia from arid regions of China, have left a rich
geological record in the form of loess deposits and ocean sediments. These
newly-mined geological records, together with a sophisticated computer model
of climate, are providing scientists with a new assessment of how the uplift
of the Himalayas and the Tibetan Plateau affect climate over a broad swath
of the world. (Image: courtesy SeaWiFS Project, NASA/Goddard Space Flight
Center and ORBIMAGE.)



From Alain Maury <>

While reading a book on french astronomer Messier, I found the following,
which talks about a comet scare in Paris in 1773, unwillingly generated by
French astronomer Joseph-Gerôme Lefrançois de Lalande. It was also certainly
the last time when the French Academy of Sciences worried about possible
collisions between near earth objects and the earth :-)))

In 1773, the French astronomer Lalande meant to present at one of the
meeting of the french sciences academy a memoir on " Réflexions sur les
comètes qui peuvent approcher la Terre" (reflexions on comets which can
approach Earth). Taken by some other activities, he could not present his
memoir, and the rumor very quickly spread that he was about to announce the
collision of a comet with Earth. Michaud, in "Bibliographie universelle
ancienne et moderne ", Paris 1854 (reed. 1966.. T .28 P 106-109) writes:

"On se demanda ce que contenait le mémoire; On y apprit que l'on
devait y voir les effets que pourrait produire une comète qui
viendrait choquer la Terre : le bruit se répandit que la comète allait
arriver, qu'elle était annoncée par Lalande. L'alarme que fit naître cette
prédiction prétendue fut si générale que le lieutenant général de police
voulut lire le mémoire ; Il ne trouvât rien qui pût motiver les terreurs
qui s'étaient répandues ; il en ordonna la prompte publication ;
Quand le mémoire fut publié, personne ne voulut y croire ; on y était
persuadé que l'auteur avait supprimé la fatale prédiction, pour ne pas
effrayer par l'annonce d'une catastrophe à laquelle il n'y avait
aucun moyen d'échapper."

"It was asked what the memoir contained. It was learned that the
effects which could produce a comet which would collide with earth would
be described. The rumor spread that the comet was going to come, and
that it was announced by Lalande. The alarm which this alleged prediction
caused was so general that the lieutenant general of the police asked to
read the memoir. He could not find anything which could cause the terrors
which had spread. He ordered its quick publication. When the memoir
was published, nobody wanted to believe it. Everybody was convinced
that he author had suppressed the fatal prediction, not to scare by the
prediction of a catastrophy to which there was no way to escape"


From Mark Anderson <>

The letter from David Morrison (CCNet, 3 May 2001) lacked any specific
examples of where Ed Grondine's version of history was inaccurate. If it is
so "grossly inaccurate" I would imagine that it would be quite easy to cite
one or two examples. Lacking such, I'd have to conclude that David Morrison
is unhappy that not everyone looks up to NASA with admiration.

I found the information about NSF responsibility for ground-based telescopes
very enlightening.  Is David Morrison saying that this is not true? I think
that David Morrison owes us an explanation with cite-able references to back
up his claim that Ed Grondine's version is not correct.

mark anderson


From New Scientist, 8 May 2001

Going up: Rockets, schmokets! If you want to get into orbit, just take the
space elevator. Karl Ziemelis heads for the top floor.

THEY say the first 100 kilometres are the best. Moments after the door
slides shut with a reassuring "ker-chunk", the acceleration takes hold,
pushing you gently but firmly into your seat. Terra firma drops
precipitously from view, and your internal organs groan in sympathy. The
base tower seems endless as it slides past the window. Then you're in open
sky, at first a seemingly infinite expanse of blue, but gradually darkening
until the Milky Way appears in all its glory. And throughout, the shimmering
blue pool that is the Earth curves away beneath you, a sight that was once
the preserve of a privileged few.

After what seems like forever--but is actually little more than 10
minutes--the acceleration eases. Now cruising at 2000 kilometres an hour, at
an altitude of 150 kilometres and rising, you begin to feel uncomfortably
buoyant in your seat. Trying to keep calm, you avoid dwelling on the fact
that for the next 18 hours the only thing stopping you from plummeting to
Earth is little more than a glorified piece of rope. A cable some 47,000
kilometres long, yet no more than a few centimetres wide, stretching from
the surface of the Earth into orbit. You are taking a trip on the space
elevator. Get ready for the ride of your life.

The idea of an elevator to the heavens may sound preposterous, like an
updated version of the Tower of Babel. But it's a serious proposition. Two
independent NASA teams recently thrashed out the technological requirements
for such a project and found them to be feasible. Extraordinarily demanding,
yes, but feasible. "You're looking at something we can seriously consider
building by the end of this century," says David Smitherman of NASA's
Marshall Space Flight Center in Huntsville, Alabama, who led one of the
teams. The space elevator--an idea long consigned to the wastebasket of
pipe-dream technologies--now looks like a real possibility. Just.


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