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CCNet 107/2002 - 17 September 2002
----------------------------------


"In 1991 a modern scientific "whodunit" was solved when geologists
identified a deeply buried, 180-kilometer-wide crater in the Yucatán
peninsula. Now known as Chicxulub, the scar resulted from the impact of a
10-km asteroid or comet nucleus 65 million years ago that triggered
global tidal waves, worldwide firestorms, and massive earthquakes. When the
planet finally returned to normal, the dinosaurs and the majority of all
then-living species had gone extinct, paving the way for mammals to
evolve and dominate Earth. Now a new study suggests that Chicxulub
might not have been an isolated event. Rather, it seems the
dinosaurs may have been the victims of a one-two impact punch."
--David Tytell, Sky & Telescope, 13 September 2002


(1) MULTIPLE COMETARY IMPACTS & THE K/T MASS EXTINCTION?
    Sky & Telescope, 13 September 2002

(2) FIRES FROM ASTEROID MAY HAVE SPARED SOME REGIONS
    National Geographic News, 16 September 2002

(3) IN A JUNGLE'S DEPTHS, A QUEST FOR ANSWERS
    Baltimore Sun, 14th September 2002

(4) SMALL NEAR-EARTH OBJECTS COULD TRIGGER NUCLEAR WAR
    Astronomy Magazine, 16 September 2002

(5) THE SEARCH FOR VULCANOIDS CONTINUES IN THE TWILIGHT ZONE
    Ron Baalke <baalke@jpl.nasa.gov>

(6) NEXT MOON EXPLORERS MAY BE ROBOTS
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(7) FOOTNOTE TO "THE CIRCLE IN THE SAND"
    Bill Mullen <mullen@bard.edu>

(8) BBC HORIZON: DINOSAUR FOOLED THE WORLD - A STORY WITHIN THE STORY?
    Hermann Burchard <burchar@mail.math.okstate.edu>

(9) LARGE TELESCOPE HELP
    Andy Smith <astrosafe22000@yahoo.com>

(10) ASTEROIDS OVERSHADOWED BY NEW THREAT
     John Michael Williams <jwill@AstraGate.net>

(11) WORKSHOP FOR MITIGATING THE EFFECTS OF PUBLIC CONCERN ON THE NASA
BUREAUCRACY:
     TWO DAYS IN WASHINGTON, 2002
     E.P. Grondine <epgrondine@hotmail.com>

(12) AND FINALLY: THE END IS NIGH: 'RUNAWAY UNIVERSE' MAY COLLAPSE IN 10
BILLION YEARS
     Andrew Yee <ayee@nova.astro.utoronto.ca>

=============
(1) MULTIPLE COMETARY IMPACTS & THE K/T MASS EXTINCTION?

>From Sky & Telescope, 13 September 2002
http://skyandtelescope.com/news/current/article_738_1.asp

DID A COMET SWARM KILL THE DINOSAURS?

By David Tytell

September 13, 2002 | In 1991 a modern scientific "whodunit" was solved when
geologists identified a deeply buried, 180-kilometer-wide crater in the
Yucatán peninsula. Now known as Chicxulub, the scar resulted from the impact
of a 10-km asteroid or comet nucleus 65 million years ago that triggered
global tidal waves, worldwide firestorms, and massive earthquakes. When the
planet finally returned to normal, the dinosaurs and the majority of all
then-living species had gone extinct, paving the way for mammals to evolve
and dominate Earth.

Now a new study suggests that Chicxulub might not have been an isolated
event. Rather, it seems the dinosaurs may have been the victims of a one-two
impact punch.

Simon P. Kelley (Open University, United Kingdom) and Eugene Gurov (National
Academy of Ukraine) reexamined the age of a buried 24-km-wide Ukrainian
crater known as Boltysh. As recently as 1993, scientists had determined this
impact to be 73 million years old. However, through a number of isotopic
experiments, Kelley and Gurov refined that date to 65.2 ± 0.6 million years.
By comparison, Chixculub's age is 65.5 ± 0.6 million years.

The overlapping uncertainties strongly suggest, (but don't prove) that these
two impacts occurred simultaneously or nearly so. By extrapolating Earth's
current cratering rate backward in time, Kelley believes a Boltysh-sized
crater should appear every 1.8 to 3.3 million years. To see two unrelated
impacts so close in age is unlikely, though not impossible. "The trouble is
that with only two craters, random impacts are not outside the realm of
possibility, says Kelley. Depsite the range of published errors, "I would be
fairly confident that there was only a 250,000-year difference [between
them]." It's "highly probable" the two craters are linked.

What's more, Earth's surface is approximately 3/5 water. Therefore, if two
related objects hit land, another three should, statistically, have splashed
down in the oceans. However, the seafloor bears no obvious trace of these -
they would have been subducted down into the mantle long ago.

If the dinosaurs did indeed endure multiple hits, scientists might be able
to say something about the nature of the impactors. Asteroids tend to travel
alone, (though pairings do exist), while comets are thought to sometimes
arrive in bunches. A gravitational disturbance in the Oort Cloud or Kuiper
Belt - the massive comet reservoirs found at the outer reaches of our solar
system - could dispatch a swarm of dirty snowballs inward toward the Sun,
and therefore Earth. Such impacts could come hundreds of thousands of years
apart. Another possible cometary multiple-impact source is a comet that
broke into pieces after passing too near a planet (the fate of
Shoemaker-Levy 9) Such impacts would happen close together.

Chicxulub was still the big killer, however. The sizes of the two craters
imply that Boltysh hit with only about 1/400 as much force.

Kelley's next step is to derive isotopic ages for other craters with roughly
comparable ages. Many craters are dated merely by stratigraphic evidence,
which is a less accurate dating method than using an isotopic chronometer.
Perhaps a third, theory-clinching 65-million-year-old crater exists, and it
has simply been assigned the wrong age. Boltysh's assumed age was in error
by some 8 million years - others could be off by that amount or more.

Kelley and Gurov present their findings in the August issue of Meteoritics
and Planetary Science.

Copyright 2002, Sky & Telescope

============
(2) FIRES FROM ASTEROID MAY HAVE SPARED SOME REGIONS
 
>From National Geographic News, 16 September 2002
http://news.nationalgeographic.com/news/2002/09/0916_020916_impactfinal.html

John Roach

About 65 million years ago a space rock slammed into Mexico's Yucatan
Peninsula and scattered high-velocity debris around Earth, igniting
wildfires in North America, the Indian subcontinent, and most of the
equatorial part of the world.

However, northern Asia, Europe, Antarctica and possibly much of Australia
may have been spared the inferno, according to a new computer simulation of
how the wildfires spread around the world.

The wildfires are thought to be a key ingredient in the concoction of
environmental changes that killed more than 75 percent of all plant and
animal life on Earth, including the dinosaurs.

"Our calculations suggest fires may have been more intense in some parts of
the world than in others and that some areas may have been spared fires
altogether," said David Kring, a planetary scientist at the University of
Arizona in Tucson. "However, other environmental effects would have affected
the spared regions."

For example, dust and smoke from the impact and fires would have obscured
sunlight causing global temperatures to plummet and acid rain to fall. Then,
the increased concentrations of carbon dioxide and other pollutants in the
air may have led to global warming.

The impact event, which created a 110 to 180 mile (180 to 300 kilometer)
diameter crater in Mexico's Yucatan Peninsula, marks the transition of the
Cretaceous Period to the Tertiary Period where mammals replaced dinosaurs as
the dominant species on Earth.

Kring along with his colleague Daniel Durda at the Southwest Research
Institute in Boulder, Colorado, detail the spread of the wildfires in the
September issue of the Journal of Geophysical Research-Planets.

Fire Model

The global wildfires sparked by the impact event that formed the Chicxulub
crater were first modeled in 1990 by planetary scientist Jay Melosh at the
University of Arizona and colleagues. Their calculation indicated that the
fires spread around the world in a single pulse.

The model developed by Kring and Durda, which they say builds on the earlier
research, shows that the fires were ignited in multiple pulses.

The impact was 10 billion times more energetic than the nuclear bombs
dropped on Hiroshima and Nagasaki, Japan in World War II, the scientists
said.

Most of the material from the collision collected around the impact site,
but according to the researchers' calculations, some 12 percent of the
debris was launched beyond Earth's atmosphere.

"The computer simulation keeps track of the velocity of material being
ejected from the crater," said Kring. "A small fraction of the material
achieves escape velocities and, thus, escapes Earth."

The debris ejected from the crater and lofted far above Earth's atmosphere
rained back down over a period of about four days, said Kring. As the debris
rained down, it heated the atmosphere and surface temperatures so intensely
that the ground vegetation spontaneously ignited.

This high energy debris concentrated both around the Chicxulub crater and on
the opposite side of the Earth around India, the researchers report.

"The pileup of debris on the opposite of the Earth occurs because material
is reaching that spot from all directions," said Kring. "Material launched
from the crater in an easterly direction runs into material launched from
the crater in a westerly direction."

As the Earth rotated, it turned beneath this returning plume of debris,
causing the wildfires to migrate to the west, as illustrated by the
researchers' computer simulation of the wildfire spread.

Modeling Assumptions

Some asteroid experts, including Melosh, question the pulsing results of the
computer model. "The pulsing is probably the result of the assumed ejecta
distribution that they choose, but there is no reason to think that what
they do is, in fact, correct," he said.

Melosh believes that the proper way to determine the pattern of wildfire
spread is to do numerical simulations of the full ejection process and then
follow the velocity and direction of the ejected debris to determine the
rain back pattern.

Kring and Durda based their computer simulation of the wildfire spread on
models of the Chicxulub impact run by Elisabetta Pierazzo, a research
scientist at the Planetary Science Institute in Tucson, Arizona, to
determine how impact angle affects the results of impact events.

"We had to estimate what the range in those launch conditions could be for a
range of plausible Chicxulub impact events," said Durda. Thus, he added,
Melosh is correct to say that their results are only as good as the
assumptions in the inputs to the model.

Durda and Kring are currently working on a way to get a direct hand-off of
the results from Pierazzo's models of the impact itself to their model that
follows the debris trajectories around the planet.

"That will allow us to more rigorously follow changes in our global fire
distribution as a result of various impact conditions," said Durda.

Nevertheless, Kring and Durda said that they have run a broad range of
possible ejecta launch conditions and certain aspects of the wildfire
pattern are the same from model to model, such as the pileup of debris on
the opposite side of the Earth from the Yucatan Peninsula.

"Different trajectories can modify the distribution of fires in small ways,
but not significantly alter the general pattern," said Kring.

Kring and Durda plan to apply their modeling efforts to other impact events,
such as the Manicouagan event in Canada some 200 million years ago and the
Popigai impact in Russia some 35 million years ago, to determine the extent
of wildfires produced.
 
Copyright 2002, National Geographic

==============
(3) IN A JUNGLE'S DEPTHS, A QUEST FOR ANSWERS

>From Baltimore Sun, 14th September 2002

MARYLAND RESEARCHERS TRAVEL TO THE BOLIVIAN WILDERNESS IN SEARCH OF EVIDENCE
OF THE IMPACT OF AN ASTEROID OR COMET.

In an expedition worthy of Indiana Jones, a team of NASA scientists left
Maryland this week to search a South American jungle for traces of a fallen
"star."

Investigators from NASA's Goddard Space Flight Center in Greenbelt are
heading this weekend into a steaming Bolivian jungle, patrolled by jaguars,
snakes and piranha, to join Bolivian colleagues at a place called Iturralde
Crater.

Barely discernible even from the air, this five-mile-wide circle in the
forest may be the bull's-eye where a hurtling asteroid or comet struck with
the force of a thousand hydrogen bombs.

Geologists have found more than 145 impact craters around the world, said
geophysicist Jim Garvin, NASA's lead scientist for Mars exploration.

But "if this can be proved to be an impact, then it is probably one of the
most recent of the bigger impacts in the Earth's history, probably as young
as the last 10,000 years," he said. "I dearly hope they can find part of the
smoking gun."

Like deer listening for gunshots in the woods, scientists are eager to
measure the size and frequency of the Earth's most recent meteorite impacts
to get a better notion of how imminent the next such climate-altering
impacts might be.

Researchers studying satellite photos in the 1980s noticed a faint but
precise circle in the forest canopy at Iturralde, where the type and color
of vegetation changed. (A radar image taken from the shuttle Endeavour in
2000, but processed just days ago, clearly shows a circular dent in the
forest floor.)

With no volcanoes, sinkholes or river bends to explain the forest circle,
the meteorite crater theory emerged. "I can't think of anything else this
thing is," Garvin said. "But I haven't been there."

Canadian experts tried in vain to reach the crater more than a decade ago.
"They claim they were turned back by too many snakes," said Compton "Jim"
Tucker, a NASA biologist with this year's expedition. "But I suspect [the
Canadians] were trying to frighten people away. They were hoping to go
back."

In 1998, Tucker and team leader Peter Wasilewski, also from Goddard, and Tim
Killeen, of Conservation International in Bolivia, launched another
expedition, with about a dozen people.

They flew first to the Amazon basin town of Riberalta, to bargain with the
native people, the Araona, for permission to pass through their land.
Araonas and their attorney demanded $1 million - the price oil companies
paid to explore the land.

"We only had $20,000 for the whole expedition," Tucker said. After six days
of talks, the team won permission to proceed, at a cost of $5,000, plus 200
D-cell batteries and 500 rounds of .22-caliber ammunition.

The expedition hired Araona bearers for $5 each a day - twice the going
rate, Tucker said. From Riberalta, they flew 130 miles to the village of
Puerto Araona. There, they boarded dugout canoes and motored down river to
Palmasola, a Brazil-nut camp.

Plunging into the forest from there, the team hacked an 11-mile trail with
machetes, guided toward Iturralde crater by signals from Global Positioning
System satellites. They moved less than a mile a day through the jungle.

The region gets 6 to 12 feet of rain annually. (Baltimore gets 42 inches in
a normal year.)

Wildlife is abundant in the absence of human hunters, whose numbers were
decimated by disease and mistreatment inflicted by outsiders a century ago
during the rubber boom.

The forest today shelters jaguars, monkeys, tapirs, giant anteaters and
armadillos. There are hundreds of species of birds, amphibians and snakes.
And insects? "You can't begin to count them," Tucker said. Four people on
the 1998 team got malaria from mosquito bites. But most troublesome are the
sweat bees.

Most tropical forests are salt-poor, Tucker explained. Human sweat draws
insects seeking the salt on skin and clothing.

"The first day there are two or three," he said. "The next day there are 200
or 300, and the next there are 2,000 or 3,000. They get caught in your
clothes, and so you get stung occasionally." The only relief lies in
frequent bathing and rinsing in rivers shared by piranha.

Hiking across the five-mile-wide crater in 1998, Tucker and his team found
an outer rim only 6 feet to 7 feet higher than the surrounding forest, and
an uplifted central area. In between was a low, boggy ring filled with
water-adapted vegetation, explaining the color change seen from space.

It was all consistent with a large impact into deep, soft sediments. Such
meteorites don't crash, Tucker said; they "splat." Their craters fill with
water and sediment, the outer rims erode, and they soon disappear.

Based on studies of craters on moons and planets where erosion is slight,
Garvin said, "you might expect, in the last few million years, five to 10
objects 100 meters in diameter or bigger" to have struck the Earth. (These
are big enough to alter the climate, but too small to trigger global
extinction.)

So where are their craters? Scientists know of only two impacts that big in
the last million years. One created the Bosumtwi crater in Ghana in West
Africa a million years ago. Because it was blasted into bedrock, the 6 1/2
-mile-wide hole was preserved, and now holds a lake.

The second dug the 8 1/2 -mile-wide Zhamanshin crater in Kazakstan, perhaps
870,000 years ago. That impact was equal to 1.5 billion tons of TNT, yet the
crater's rim today rises barely 100 feet above the desert.

Scientists think that's because the Zhamanshin event struck soft sediments,
and quickly eroded. They have been searching for others, eager to fill a
critical gap in their charts of the largest, most recent impacts. "If this
one [Iturralde] were proven - a thousand-megaton TNT-equivalent event in the
last 10,000 years - it would be a major new hinge point on that curve,"
Garvin said.

An impact that big at Iturralde would have plowed several miles into the
sediment and vaporized, its energy hurling debris high into the atmosphere.

The 1998 NASA team had no equipment to drill through deep sediments or do
seismic mapping of the bedrock. So, they gathered rocks and shallow soil
core samples, looking for "shocked" and melted minerals typical of meteorite
impacts. "We found a few tantalizing clues in them, but nothing that was
definitive," Tucker said.

Their work was cut short by the arrival of the rainy season, and fear that
rising water might strand them in the jungle. Abandoned by their bearers,
they carried out their gear and samples, and began plotting the next
mission.

The 2002 expedition is being led and funded by NASA, at a cost of $20,000,
with in-kind support from a Bolivian museum and Conservation International.

"Hopefully we will not repeat the same mistakes," Tucker said. This time,
only part of the team will hack its way in on foot; the rest will use a
helicopter. They plan more geological mapping and dating, and a better
search of eroded riverbanks for telltale rocks, or chemical traces of the
meteorite.

They also hope to launch a remote-controlled model airplane carrying a
magnetometer. The 1/3 -scale Cessna will crisscross the area, mapping the
strength and direction of magnetic field lines inside and outside the
crater. Goddard scientists will then look for magnetic disturbances typical
of large impacts.

"I'm not convinced the [work] is going to bear fruit," Garvin said.
Iturralde sediments may not reveal magnetic changes the way shattered
bedrock would. Proof may demand gravity and seismic studies, requiring more
people, heavy equipment and lots more money.

But Goddard astrophysicist Mario Acuna, who built one of the expedition's
two magnetometers, is optimistic. If the team can just manage to complete
the work under difficult jungle conditions, he said, they should get the
proof they're seeking.

"All indications are that this is a soft impact crater," he said. "If they
don't find any magnetic imprint of this, we will have to scratch our heads
and say, `What happened here?'"

The public can follow the Iturralde expedition at www.blueiceonline.org.

Photo(s) 1. In 1998, researchers traveled toward the Iturralde Crater, where
scientists believe an asteroid or comet struck the Earth./ 2. During the
1998 expedition, Tom Albert, a Howard County science teacher, searches for
evidence of a meteorite impact./ 3. ITURRALDE CRATER/

Copyright © 2002 The Baltimore Sun. All rights reserved.

============
(4) SMALL NEAR-EARTH OBJECTS COULD TRIGGER NUCLEAR WAR

>From Astronomy Magazine, 16 September 2002
http://c.moreover.com/click/here.pl?e47394687&e=6513     

Small Near-Earth Objects Could Trigger Nuclear War
An NEO warning system could prevent high-strung countries from being jolted
into a nuclear conflagration.

by Kelly Kizer Whitt

Near-Earth objects (NEOs) pose a threat to our global security, and not just
from a catastrophic impact. A large meteorite exploding in Earth's
atmosphere could trigger a nuclear war.

Such a scenario was in the making on June 6, 2002. Just as the tensions
between India and Pakistan were reaching their boiling point, a meteor
exploded as it entered the atmosphere over the Eastern Hemisphere, causing
an energy release of 12 kilotons, equivalent to the blast that destroyed
Hiroshima. Fortunately, the bright flash and damaging shock wave of the
detonating meteorite occurred over the Mediterranean Sea, just west of the
disputed Kashmir region. If the explosion had happened a little earlier
while it was over the countries in conflict, the confusion and panic could
easily have sparked a nuclear response from either country.

While the United States was able to quickly determine the source of the
explosion, India and Pakistan, as well as most other countries, do not have
the resources available to distinguish whether an explosion's source is
natural or man-made. Brigadier General Simon P. Worden, the U.S. Space
Command's deputy director for operations at Peterson Air Force Base in
Colorado, would like to change that.

The Department of Defense already tries to notify nations that are facing
potential missile attack of meteorite strikes; however, the data they
collect is through classified systems, which can result in a several-week
delay before the information is released. Worden recently told the
Commission on the Future of the U.S. Aerospace Industry in Washington, D.C.,
that an NEO warning center could be established to assess and release the
data more quickly without jeopardizing sensitive information. He believes
that no more than 10 extra people in the current centers would be required
to catalog and provide warning of future NEO threats.

Ground-based telescopes are already detecting and defining the orbits of
large, kilometer-sized objects. But there is no good system currently in
place to find smaller NEOs. "Just about everyone knows of the 'dinosaur
killer' asteroids," Worden says. "These are objects, a few kilometers
across, that strike on time scales of tens of millions of years. While the
prospect of such strikes grabs people's attention and makes great
catastrophe movies, too much focus on these events has been
counterproductive. We need to focus our energies on the smaller, more
immediate threats."

In 1908, the well-known Tunguska meteorite exploded in the skies above
Siberia and devastated an area 80 kilometers in diameter. This space chunk
was probably not more than 100 meters in diameter but exploded with the
energy equivalent of a 10 megaton nuclear blast, even though it never hit
the ground. In 1996, a meteorite exploded over Greenland with a force of 100
kilotons (much greater than the June Mediterranean blast of 12 kilotons). If
the Greenland or Tunguska events had occurred over populated areas, they
would have caused massive fatalities.

In addition to igniting a nuclear war, another worst-case scenario is a
100-meter or smaller meteorite striking the ocean near a heavily populated
seacoast. "The resulting tidal wave could inundate shorelines for hundreds
of miles and potentially kill millions," says Worden.

"There are hundreds of thousands of objects this size that come near Earth.
We know the orbits of just a few," Worden sums up. His call for the creation
of a better NEO detection system would make Earth safer from threats from
above. Until then, we have to wait until after an event occurs before we
learn about it and hope that these incidents are limited to isolated corners
of the globe.

Copyright © 1996-2002 Kalmbach Publishing Co. 
 
============
(5) THE SEARCH FOR VULCANOIDS CONTINUES IN THE TWILIGHT ZONE

>From Ron Baalke <baalke@jpl.nasa.gov>

http://planetary.org/html/news/articlearchive/headlines/2002/VulcanoidSearchContinues.html

The Search for Vulcanoids Continues in the Twilight Zone
By A.J.S. Rayl
The Planetary Society
12 September 2002

As the autumnal equinox approaches, scientists Daniel Durda and Alan Stern
will strap into the backseat of an F/A-18B fighter jet at NASA's Dryden
Flight Research Center in California, then take to the stratosphere to
continue their airborne search for vulcanoids, the string of small asteroids
that may be circling the Sun within the orbit of Mercury.

During the early morning hours before sunrise, Stern - on September 17 and
18, and Durda -- on September 19, will rocket up to 49,000 feet to snap
images of the virtually unexplored region of the sky near the Sun with their
modified, miniature video camera known as the Southwest Ultraviolet Imaging
Systems Aircraft (SWUIS-A).

Durda and Stern, both of the Southwest Research Institute (SWRI) in Boulder,
Colorado, conducted their first dedicated airborne search for these elusive
rocks with the SWUIS-A last Spring. Basically, the imaging system is an
85-millimeter camera that shoots images at 60 frames per second, then sends
them to a recorder where they are stored in a continuous stream of video.
Initially designed at SWRI in 1996 to operate on the space shuttle, the
SWUIS-A not only allows the researchers to obtain images of objects that are
as much as 600 times fainter than what is visible to the naked eye, but,
Durda points out, allows them to take time exposures to look at objects
fainter than normally could be seen in any individual 1/60-second exposure.

Although they did not find any vulcanoids in the some 100,000 images
gathered on their first flights, this time up they'll be using a brand new
lens on the SWUIS-A that will allow them to capture even fainter objects.

The one thing they did find on their first series of exploratory flights,
however, was that the high-performance fighter jets make excellent
telescopic platforms. "Our techniques of flying to high altitudes to reduce
the brightness of the twilight sky does indeed work, giving us the distinct
advantages of range and altitude over ground-based searches," says Durda, as
he takes a break from making up the requisite star charts and conducting
last-minute equipment checks.

The vulcanoid enigma

At the heart of the search lingers some controversy as to whether or not
vulcanoids actually exist. While theoretical models indicate a few hundred
of the relatively small rocks, ranging in size from one to 20 kilometers in
diameter, could have survived the harsh environment of the inner Solar
System, skeptics argue that any vulcanoids that may have once existed would
be gone now because the harsh collisional environment would have ground them
away to dust some time ago.

But absence of evidence is not evidence of absence, as the saying goes, and
discovering a vulcanoid could provide a major breakthrough for studies of
the Solar System and of Mercury. "Since they lie so near the Sun, they could
contain traces of the first materials that formed within the inner Solar
System, and finding one, being able to study the physical properties, would
help astronomers better understand the conditions in the solar nebula from
which the planets - including our home planet Earth - formed," elaborates
Durda.

If they do exist, vulcanoids would be visible in the region inward of
Mercury, the area where it would be reasonable to find any remnants of the
little planetesimals from which the planets formed. At this point, says
Durda, "we have kind of hit the limits about what we can theorize about and
the only way to know for sure is to go up there and look."

Ground-based searches for vulcanoids have been conducted for years during
small windows of time that open during solar eclipses and in the twilight
moments, just after sunset and before sunrise, but this particular region of
the sky is extremely difficult to search from the ground because of such
factors as atmospheric hazes, turbulence and glare from the Sun. So Stern,
the director of the space studies department at SWRI who led the development
of the airborne astronomy program, and Durda, a senior research scientist,
proposed taking a look from a higher perspective, and NASA's Planetary
Astronomy program and the National Geographic Society funded the study.

Into the twilight zone

Durda and Stern will arrive at Dryden on Monday, September 16. "While Alan
is going through egress and ejection refresher training, I'll be working
with the NASA engineer to make sure the equipment is installed in the
aircraft properly," Durda explains. "Each morning, we'll take off around
05:15 hours and fly north over Edwards Air Force Base, pointing our SWUIS-A
imaging system out the right side of the cockpit to sweep our search area in
the eastern sky, about a 6-1/2 by 5-1/2 degree patch, in the morning
twilight."

The best time to search for vulcanoids is at the equinox - the first day of
Spring, the first day of Fall, Durda informs. "These are the times when the
ecliptic, the plane of the Solar System in which objects tend to orbit, is
as vertical as possible to the horizon."

The SWUIS-A system they use for these vulcanoid searches is, Durda notes,
"essentially the same system designed at SWRI for the shuttle, but we'll use
a slightly different camera that is optimized from broadband visible to a
little bit into the near-infrared, to about 800 nanometers."

Durda and Stern had hoped to soar up to 80,000 feet in one of the USAF's U-2
trainers, but the aircraft is busy, so they are returning to the fighter
jets. Not surprisingly, neither is complaining. "The F/A-18B is a rocket
with wings and for civilian scientists to get the opportunity to actually
fly in these jets is an amazing experience," says Durda. So amazing in fact
that they're balancing the number of times each gets to go aloft. Stern will
fly the first two flights with NASA pilots Frank Batteas and Gordon
Fullerton, a former shuttle commander, with Durda taking off on the third
flight with pilot Craig Bomben. "The last time, I got to fly two flights,
and this time Alan gets to fly two," explains Durda.

Going up to get down (in magnitude)

During the series of flights last Spring, the duo completed nine search
fields over the area around the twilight near the Sun per flight, all of
which were compared. "We were able to see stars in our images down to
astronomical magnitude V= 9.5 or so - about a magnitude fainter than people
have reported for previous ground-based vulcanoid searches and comparable to
the results we obtained using data gathered by the Solar and Heliospheric
Observatory (SOHO) spacecraft while it was monitoring the solar corona and
solar activity," says Durda.

Despite the fact that no candidate vulcanoids popped into view, Durda and
Stern did see "lots" of faint stars. "We weren't really all that surprised
that we didn't find any vulcanoids on that trip considering that we've
already searched down to nearly that magnitude limit in previous searches,"
Durda admits. "You really do need to get down into an 11, 12, 13 magnitude.
Now the instrument we have is capable of getting down to 12 or 13 if the sky
is dark enough. (Remember each magnitude is about a factor of two and a half
in brightness.) So if we could make the sky darker, we could do an even
better job."

That is exactly what they're planning on doing this time out.

Since the availability of the U-2 had been in question, particularly in
light of the events of 9-11, Durda and Stern began strategizing about how to
get the background sky as dark as possible right after they returned from
their flights last April. "While one way is to go higher - which could be
done in the U-2, the other option was to find a different lens for the
camera system," Durda says. So even as they tried to secure a cruise in a
U-2, they obtained a new lens that will 'zoom in,' using a longer focal
length for slightly deeper images of the sky in the search area. "When we
zoom in, we'll be looking at a smaller patch of the sky, but what we'll be
doing, in effect, is spreading what sky brightness there is there out over
more pixels in the imagers, while the stars, which are just point sources,
stay, per pixel, the same brightness essentially."

Durda tested out the new lens a few weeks back during the Perseid meteor
shower and found that it should allow them to go about two magnitudes
fainter than the previous lens. "If you extrapolate, that means we'll be
able to go from a magnitude of about 9.5 down to somewhere between 11 and
11.5," he says. "That will help a lot."

Once the flights are over and the images are collected, Durda and Stern will
process and analyze the data just like before. "Basically, we will digitize
and clean up the images to eliminate any movement created by the motion of
the aircraft, and to get rid of variations in sky brightness background due
to imperfections in the system - what astronomers refer to as flat fielding
the images," Durda explains.

Then, an individual star in those images will be chosen and identified for
the imaging system's software, which, in turn, will reposition all the
individual frames so that the chosen star is in the same position in every
frame or in other words reconvert them back into one long time exposure. The
hope is that they'll find one or more of the elusive vulcanoids. Meanwhile,
they're still working to line-up a ride in the U-2 for at least one more
search next Spring before this study is completed.

========
(6) NEXT MOON EXPLORERS MAY BE ROBOTS

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

[ http://www.upi.com/view.cfm?StoryID=20020912-052834-1728r ]

Thursday, September 12, 2002, 6:29 PM EDT

Next moon explorers may be robots
(Reported by Irene Brown, UPI Science News, at Cape Canaveral, Fla.)

TAOS, N.M. (UPI) -- University of Hawaii geologist Jeffrey Taylor said
Thursday he sees the day when swarms of tiny robots scurry around the
surface of the moon, probing for water, minerals and
other resources that will be needed for lunar settlements and industries.

The miniature robots would relay their findings to all-terrain rovers, which
would then explore the most promising locations.

"We are developing a strategy that represents a comprehensive, integrated
program to prospect for resources throughout the solar system," Taylor said
during the opening day of a three-day conference titled, "The Moon Beyond
2002: Next Steps in Lunar Science and Exploration."

Buoyed by a National Research Council recommendation for a new science
mission to retrieve samples from a deep crater on the moon, scientists and
engineers are hoping to rekindle support for lunar exploration, which has
been largely dormant since the completion of the Apollo program in the early
1970s. Two notable exceptions: a technology demonstration project called
Clementine, which flew in 1994 and produced the first global map of the
moon's surface, and NASA's Lunar Prospector spacecraft, which in 1999 mapped
the moon's minerals, gravity and magnetic fields.

"We have a good collection of remote sensing data for the moon," Taylor
said. "Prospecting can begin immediately."

Identifying valuable deposits, however, will require better understanding of
lunar composition, geologic history and geologic processes.

For example, Taylor said: "The bone-dry nature of the moon -- except perhaps
at the poles -- eliminates all ore deposits associated with aqueous fluids.
On the other hand, ore-forming
processes might have operated on the moon, but not on Earth."

In addition to understanding what kinds of resources are on the moon and how
they could be used, Taylor and colleagues at the University of Hawaii's
Institute of Geophysics and Planetology want to develop curriculum to
prepare field geologists for lunar exploration.

"We have to learn what we'll need to live off the land," said Linda Martel,
a planetary geologist and remote sensing expert who works with Taylor.

In addition to developing maps of ore deposits, the team is working on plans
for an army of microrobots, which could number in the thousand or millions,
to physically locate the resources on the moon's surface. Prototype robotic
field geologists already have been tested on Hawaiian lava flows.

"We're working on a strategy of how to find the resources," Martel said.

Lunar exploration advocates say it makes more sense to learn to live off a
relatively close-by base on the moon, rather than focusing on Mars.

"We really need to get our space legs more under us before we go on to
Mars," said David Gump, president of LunaCorp, which is developing a lunar
orbiter and a follow-up robotic probe.

"Expect for the six Apollo landing sites, we really don't know much about
what's on the moon," Gump said. "Mars seizes the imagination, but the
technology just isn't here yet. We need to get back to the moon first."

Copyright © 2002 United Press International. All rights reserved.

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

(7) FOOTNOTE TO "THE CIRCLE IN THE SAND"

>From Bill Mullen <mullen@bard.edu>

Dear Benny,

I would like to acknowledge certain scientists, several of whom I
encountered on CCNet, for material I either quoted or paraphrased in "The
Circle in the Sand":

-- Jim Pinkerton, CCNET 7/26/02, for the phrases "nerves strained to the
nuking point" and "the asteroidal equivalent of 9/11".
--Sharad Master, CCNET 11/16/01, on the impact site at the Al 'Amarah
marshes.   
-- Stuart Kauffman, At Home in the Universe (Oxford, 1995), p. 23 for the
phrase "order for free", and pp. 28-30 for the account of sandslides and
"self-organized criticality" (for which he acknowledges Per Bak and Kan
Chen, "Self-Organized Criticality", Scientific American, January 1991, pp.
46-54.
-- Stephen Wolfram, A New Kind of Science (Wolfram Publications, 2002),
passim, for development of the notion, used frequently in chaos and
complexity theory, that "Give any system, however simple, a simple set of
rules/ it may soon become, on its own, too random or too complex to
compute."

Bill Mullen

MODERATOR'S NOTE: Bill's poem "The Circle in the Sand" is available online
(CCNet 9/11 issue) at
http://abob.libs.uga.edu/bobk/ccc/cc091102.html

==============
(8) BBC HORIZON: DINOSAUR FOOLED THE WORLD - A STORY WITHIN THE STORY?

>From Hermann Burchard <burchar@mail.math.okstate.edu>

Dear Benny,

BBC Horizon-online, THE DINOSAUR THAT FOOLED THE WORLD tells a great story:
"In 1999, National Geographic magazine published astonishing evidence of a
Chinese fossil that looked to be half bird and half dinosaur. Unfortunately,
it was literally that...  new finds in China showed Archaeoraptor to be an
extremely clever fake. The head and upper body of a hitherto unidentified
bird had been glued onto the tail of a previously unknown dinosaur. It was a
journalistic disaster for National Geographic Magazine."

However, it was all to the good. Soon, genuine feathered dinosaurs were
discovered as a result of frantic searches in Liaoning province, thus
clinching the argument in favor of avian descent from dinosaurs.
  http://www.nature.com/nsu/980702/980702-8.html

A potentially even bigger story, overlooked by both BBC Horizon and National
Geographic, can be found inside this fantastic tale of poor, fossil hunting
farmers and fossil dealers in Liaoning Province in Northern China, trying to
make a living from often fragmentary hence low-priced fossils of early
Cretaceous origin 130 M years ago.

Let me explain, my starting point being another quote from the BBC Horizon
transcript:

"Xu Xing knew that if he could find another specimen he might be able to
learn more about this mysterious creature.  It had come from the Liaoning
region in Northern China, one of the richest fossil areas in the world. The
rock here is formed by LAYERS OF VOLCANIC ASH which over 130 million years
ago buried a wetland that had teemed with wildlife.  It's created perfect
conditions for preserving even the most delicate creatures." [My emphasis.]

Sound familiar?  Wheels within wheels:

It just so happened (as I maintain) that 130 M years ago in Sibiria to the
North of China, a SUPERVOLCANO OR HOTSPOT, now at Mount Kilauea, Hawaii, was
rummaging around, spewing ash (exact details of its motion at that time may
not yet be known). It's simmered down a bit by now, but even so, it
continues to erupt in spectacular lava fountains. In the intervening 130 M
years, since the time when it was positioned underneath Sibiria north of
China, it's moved east by about 5,000 km (or rather, Earth's crust has slid
over a nearly stationary hotspot).

Undoubtedly, it was one of the supervolcanic eruptions of the Hawaiian
hotspot in its ancient Sibirian avatar that buried the two parts of the fake
Archaeoraptor fossil in present-day Liaoning province 130 M years ago.
Nothing on this is mentioned by BBC, of course.

Somewhat earlier the new continent of Sibiria had begun to form of magma
poured forth and ash spewed out from the hotspot, beginning with the West
Sibirian Basin (impact site) and the great Putorana Mountains [SCIENCE 296,
1846 (2002), CCNet, 7 June 2002, and 11 June 2002 (my comments)]. A
Mongol-Okhotsk ocean at first lay between Sibiria and Asia as shown by Rob
Van der Voo, Wim Spakman, and Harmen Bijwaard from Ann Arbor and Utrecht:
"... the Siberian and Mongolian continental plates converged between 200
million and 150 million years ago...".
  http://www.umich.edu/~newsinfo/Releases/1999/Jan99/r011999a.html

Thus, by late Jurassic times, this ocean had closed down and Sibiria had
become sutured to the main continent of Asia.  By our time, the last remnant
of the former ocean is the Sea of Okhotsk, east of Magadan.  Not by
coincidence, Magadan is considered the eastern terminus of the Sibirian
traps erupted from the hotspot.  Any fossils from the shoreline of this
dwindling ocean probably are buried under massive lava flows and ash beds
because too close to successive calderas.  Further to the South lay the
wetlands in Liaoning province buried under layers of volcanic ash cited by
BBC Horizon, but now exposed in surficial strata.

[Some geologists make the argument that subduction of the Hawaiian chain in
its parts older than 85 M years under the Aleut-Kuril trenches militates
against identifying the Hawaiian hotspot with the Sibirian one, the one
erupting the Sibirian traps.  But, the chain meets the Kuril and Aleut parts
of the trench exactly at a large cusp indentation, clear evidence for
considerable resistance to subduction by the Emperor part of the Hawaii
chain.  Even with allowance for some subduction, a continuation of the
Emperor chain underneath the Sea of Okhotsk probably exists and is
identifiable, a link-up to the Sibirian traps which run from the West
Sibirian Basin impact origin to the Putorana to Magadan.  Complications
arise from a possible second South Kara Sea impact origin hotspot, and
perhaps a third one from Mount Meishan in South China - three suspected
impact sites at 250 M years ago of fragments of a giant comet - almost
certainly not an asteroid.]

A similar report on another BBC Horizon program, SUPERVOLCANOES can throw
additional light on how the Liaoning fossils came to be buried under layers
of ash:  Here it was, not dinosaurs 130 M years ago, but poor old rhinos and
other mammalia mainly ungulate fauna only 10 M years ago in NE
Nebraska that were suffocated and buried by LAYERS OF VOLCANIC ASH. For
pictures see:
   http://www-museum.unl.edu/research/vertpaleo/ashfall.html

As it turned out, the Nebraska ashfall was from one of the resurgent caldera
eruptions of the Yellowstone hotspot, the Bruneau-Jarbidge [sic!] caldera
(60 mile diameter) part of the Owyhee Mountains of SW Idaho, located almost
1000 miles West of Nebraska, an astonishing distance:
   http://www.bbc.co.uk/science/horizon/1999/supervolcanoes_script.shtml

>From this we can picture the hotspot erupting to form the Liaoning fossils
may not have been located very near the site of the wetlands. See two recent
items on CCNet, both 22 July 2002:

a) VOLCANOES A BIGGER THREAT THAN ASTEROIDS OR COMETS (although I cannot
agree with the statement; these supervolcanoes are almost certainly of
exclusively impact-generated mantle plume origin).

b) MORE BLASTS FROM THE YELLOWSTONE PAST:  Geologist Barbara Nash and her
team at the University of Utah ingeniously established high precision timing
of the Yellowstone supervolcanoes from ash layers which they discovered and
dated in ocean floor deposits in both the Pacific Ocean and
the Gulf of Mexico.

One can only hope that similar residual geological strata will eventually
lead to a more complete history of the supervolcano predecessors of Mount
Kilauea.

However, the Utah team doesn't address cosmogenic impacts. The site must be
just south of the tri-state corner of Nevada, Oregon, and Idaho. One local
publication refers to the impact theory for Yellowstone as an "outrageous
suggestion based on circumstantial evidence."

Regards,
 Hermann

==============
(9) LARGE TELESCOPE HELP

>From Andy Smith <astrosafe22000@yahoo.com>

Hello Benny and CCNet,

It was great to see the web photo of asteroid 2002 NY40, taken by the the
4.2-m William Herschel Telescope (WHT), on 17,18 August. We understand that this
was also the first application of adaptive optics to the detailed study of a near-earth object
(NEO). The WHT is a member of the excellent Isaac Newton Group (ING) of
telescopes, located in the Canary Islands and it is one of the largest.
http://www.ing.es/PR/press/2002NY40.jpg

As you know, most of the 100,000+ dangerous NEO population is too small to
find (less than abs. mag. 20 and smaller than 500 meters or so), using the
existing search equipment and we desperately need help from the larger
equipment.

We have been urging the large survey telescopes (like the Sloan and the
Newton) to join us in this vital search and we are very happy to see efforts
like the WHT photo, the work that is planned for the Newton, as part of the
UK effort,  and the studies that have been done using the Sloan. We need
teams and priorities, on these excellent telescopes, which will help us to
complete the critical NEO inventory within the next decade or two and and
before the next hit, if it is humanly possible. There is also a pressing
need to expedite the funding and construction of the 8.4 meter
Large-aperture Synoptic Survey Telescope (LSST) and to get it into the hunt.

2002 Hunt

LINEAR and NEAT are continuing to feed the MPC data base at an impressive
rate and we may have another record year. About 25% of the discoveries are
larger than a kilometer. The distribution is skewed toward the larger
objects, because the equipment has difficulty finding the smaller objects.
In a full-spectrum search, the larger-than-a-kilometer objects would be a
few percent (less than 5) of the total.

It is worth noting that the larger members (600-800 meters) of the small
group are more destructive than a large global nuclear war and are very
capable of plunging us all into a multi-year NEO winter and the massive
starvation that would come with it. Our comparisons of NEO impacts with the
largest volcanic explosions clearly show this.

We continue to be concerned about the many NEO search teams that are not
producing much new data and we urge the programs funding these efforts to
see that they are adequately staffed. We also are concerned about the
support being provided to our major data center (the Minor Planet Center),
as the flow of NEO data continues to increase. We owe so much to the
excellent MPC team and we strongly support them.

With all of the progress we have made, in the last decade (and all the work
done over the entire 20th Century), we still have less than 2% of the
critical NEO data needed for our defense.

Again, thanks to the ING and the Sloan folks for their help and we are
looking forward to their continued support.

Cheers,
Andy Smith for the International Planetary Protection
Alliance (IPPA) astrosafe22000@yahoo.com

============
(10) ASTEROIDS OVERSHADOWED BY NEW THREAT

>From John Michael Williams <jwill@AstraGate.net>

Hi Benny.

Asteroids, smashteroids!

Here's the REAL threat:
http://www.wired.com/news/games/0,2101,55092,00.html

> 'Blizzard' of Cheaters Banned
> By Noah Shachtman
>
> "Cheating in online games threatens the shared basis of
> the world," Kurt Squire, senior editor of Joystick101, a
> gaming site, wrote in an e-mail.
> ...
> This latest move is Blizzard's most dramatic step to
> curb cheating. The 14,000 cancellations appear to
> be the largest mass banning in the history of computer
> gaming, according to Justin Carmony, founder
> of Counter Hack, an anti-cheating website.
> ...
--
                         John
                     jwill@AstraGate.net
                     John Michael Williams

============
(11) WORKSHOP FOR MITIGATING THE EFFECTS OF PUBLIC CONCERN ON THE NASA
BUREAUCRACY:
     TWO DAYS IN WASHINGTON, 2002

>From E.P. Grondine <epgrondine@hotmail.com>

Hello Benny -

Last week I spent two days at the "Workshop on Scientific Requirements for
Mitigation of Hazardous Comets and Asteroids". As after my study of the
Bazas impact I was rather tired, I estimated that 2 days of this would be
just about as much of it as I could stand. As it turned out, it was more
than I could stand.

Tuesday morning I had received the abstracts which contained Morrison's
entirely misleading  estimate of the impact hazard: you know the one, the
one where Morrison takes the lowest estimate of the number of large
asteroids which he can find, uses that and some means to estimate the total
numbers for smaller asteroids, which in fact are completely unknown, and
then "forgets" to add in the impact hazard arising from comets, which appear
to have been responsible for about 50% of the recent impacts, and are
implicated in a large number of Extinction Level Events. About the only
question left was how the Workshop was going to be manipulated to give this
fraud the guise of scientific respectability. The answer came Thursday
afternoon.

Since NASA management already has in hand a report by a skilled engineer on
exactly how to deal with the impact hazard, a report which NASA is doing its
best to ignore, the event more properly should have been called the
"Workshop for Mitigating the Effects of the Public's Concerns on the
Bureaucracy". This should come as little surprise to you, as as an
anthropologist you are well aware the primary goal of any social
organization is its own survival. That said, let's start at the beginning...

"I DID NOT HAVE SEX WITH THAT WOMAN."

Another principle of which you are aware of as an anthropologist is that the
goal of any ritual, any meeting such as this one, its outcome, is fairly
well planned in advance. Thus to determine a meetings's goal it is very
important to determine exactly who organized the meeting and how it came
about. The search for an answer to this simple question took a day and a
half and produced some interesting results:

FULL SPIEL at http://abob.libs.uga.edu/bobk/ccc/ce091702.html

=============
(12) AND FINALLY: THE END IS NIGH AS 'RUNAWAY UNIVERSE' MAY COLLAPSE IN 10 BILLION YEARS

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

Stanford University
Stanford, California

CONTACT: Mark Shwartz, News Service
(650) 723-9296; e-mail: mshwartz@stanford.edu

9/13/02

'Runaway universe' may collapse in 10 billion years, new studies predict

By Mark Shwartz

The recent discovery that the universe is expanding at an ever-increasing
rate has led many astronomers to forecast a dark and lonely future for our
galaxy. According to some predictions, the rapidly accelerating universe
will cause all galaxies to run away from each other until they are no longer
visible. In this widely accepted scenario, our own Milky Way will become an
isolated island adrift in a sea of totally black space 150 billion years
from now.

But two new studies by Stanford University cosmologists suggest that it may
be time to rethink this popular view of a "runaway universe." Instead of
expanding exponentially, our cosmos may be in danger of collapsing in a
"mere" 10 to 20 billion years, according to the Stanford team.

"The standard vision at the moment is that the universe is speeding up,"
said physics Professor Andrei Linde, "so we were surprised to find that a
collapse could happen within
such a short amount of time."

Linde and his wife, Renata Kallosh -- also a professor of physics at
Stanford -- have authored two companion studies that raise the possibility
of a cosmic "big crunch." Both papers are available on the physics research
website, www.arXiv.org .

"We tried our best to come up with a good theory that explains the
acceleration of the universe, but ours is just a model," Linde noted. "It's
just part of the answer."

If the Linde-Kallosh model is correct, then the universe, which appears to
accelerating now, will begin to slow down and contract.

"The universe may be doomed to collapse and disappear," Linde said.
"Everything we see now, and at a much larger distance that we cannot see,
will collapse into a point smaller than a proton. Locally, it will be the
same as if you were inside a black hole. You will just discontinue your
existence."

Einstein's "blunder"

The fate of the cosmos has been hotly debated for decades.

In the early 20th century, Albert Einstein, along with most physicists,
believed that the universe was static -- even though the equations he
developed for his general theory of relativity in 1917 suggested that space
itself was either contracting or expanding.

To ensure that his new theory was consistent with nature, Einstein invented
the "cosmological constant": an arbitrary mathematical term he inserted into
his equations to guarantee a static universe -- at least on paper.

To Einstein, the cosmological constant may have represented some kind of
invisible energy that exists in the vacuum of empty space -- a force strong
enough to repel the gravitational force exerted by matter. Without this
mysterious vacuum energy opposing gravity, the universe
eventually would crash in on itself, according to general relativity theory.

But observations by astronomer Edwin Hubble and others in the 1920s proved
that distant galaxies are not stationary but are, in fact, moving away from
one another. Since the universe was expanding, Einstein no longer needed an
antigravity factor in his equations, so he rejected the cosmological constant as irrelevant.

"First Einstein introduced the cosmological constant in his equations, then
he said that this was the biggest blunder of his life," Linde observed. "But
I recently heard that, apparently, he still liked the idea and discussed it
many years later -- and continued writing equations that included it."

Dark energy

Fast-forward to 1998, when two independent teams of astronomers discovered
that not only is the universe expanding, it is doing so at an ever-faster
pace. Their findings were based on observations of supernovae -- exploding
stars that emit extraordinarily bright light.

A supernova is a rare event, but new telescopes equipped with sophisticated
electronic sensors allowed the research teams to track dozens of stellar
explosions in the sky. What they saw astonished the world of astronomy: The
supernovae, it turned out, actually were speeding up at a rate that outpaced the predicted
gravitational pull of matter.

What force could be strong enough to overcome gravity and cause the universe
to accelerate? Perhaps Einstein was right all along -- maybe there is some
kind of vacuum energy in space. Einstein called it the cosmological
constant, and 80 years later, astronomers would give this invisible force a
new name -- dark energy.

"The supernova experiments four years ago confirmed a simple picture of the
universe where approximately 30 percent of it is made of matter and 70
percent is made of dark energy -- whatever it is," Linde observed.

Overnight, a concept that Einstein had rejected was now considered the
dominant force in the universe.

"The cosmological constant remains one of the biggest mysteries of modern
physics," Linde pointed out.

Negative energy

Current predictions that dark energy will continue to overwhelm gravity and
produce a runaway universe are based on the assumption that the total
density of dark energy in the universe is greater than zero and will remain
so forever.

This seems obvious at first glance, since logic dictates that the density of
dark energy has to be a positive number. After all, how could the universe
be filled with "negative energy"?

But in the strange world of quantum physics and elementary particle theory,
everyday logic doesn't always apply.

"During the last year, physicists came to the realization that it is very
difficult to understand the origin of positive dark energy in the most
advanced versions of elementary particle theory -- such as string theory and
extended supergravity," Linde said.

"We have found that some of the best attempts to describe dark energy
predict that it will gradually become negative, which will cause the
universe to become unstable, then collapse," he added. "People who studied
general relativity many years ago were aware of this, but to them, this was
an academic possibility. It was weird to think about negative vacuum energy
seriously. Now we have some reasons to believe it."

The Linde-Kallosh model produced another surprising result: The cosmos will
collapse in 10 to 20 billion years -- a timeframe comparable with the age of
the universe, which is estimated to be about 14 billion years old.

"This was really strange," Linde recalled. "Physicists have known that dark
energy could become negative and the universe could collapse sometime in the
very distant future, perhaps in a trillion years, but now we see that we
might be, not in the beginning, but in the middle of
the life cycle of our universe."

The good news, wrote Linde and Kallosh, is that "we still have a lot of time
to find out whether this is going to happen."

Cosmic bubbles

Linde is quick to acknowledge that the collapsing universe scenario is not
the final word on the fate of the cosmos.

"Astronomy is a science once known for its continuous errors," he
quipped."There was even a joke: 'Astrophysicists are always in error but
never in doubt.' We are just in the very beginning of our investigation of
this issue, and it would be incorrect to interpret our results as a reliable
doomsday prediction. In any case, our model teaches us an interesting
lesson: Even the most abstract theories of elementary particles may end up
having great importance in helping us understand the fate of the universe and
the fate of humanity."

Direct observation of space with state-of-the-art telescopes, satellites and
other instruments will answer many unresolved questions, he added. "We're
entering the era of precision cosmology, where we really can get a lot of
data, and these data become more precise. Perhaps 10 years, 20 years, 30
years, I don't know, but this is the timescale in which we will get a map of
the universe with all its observable parts. So things that were a matter of
speculation will gradually become better and better established."

Linde helped pioneer inflationary cosmology -- the theory that the universe
began not with a fiery big bang but with an extraordinarily rapid expansion
(inflation) of space in a vacuum-like state. According to inflationary
theory, what we call the universe is just a minute fraction of a much larger
cosmos.

"The universe actually looks, not like a bubble, but like a bubble producing
new bubbles," Linde explained. "We live in a tiny part of one bubble, and we
look around and say, 'This is our universe.'"

If our bubble collapses into a point, a new bubble is likely to inflate
somewhere else -- possibly giving rise to an entirely new form of life,
Linde said.

"Our part of the universe may die, but the universe as a whole, in a sense,
is immortal -- it just changes its properties," he concluded. "People want
to understand their place in the universe, how it was created and how it all
will end -- if at all. That is something that I would be happy to know the
answer to and would pay my taxpayer money for. After all, it was never easy
to look into the future, but it is possible to do so, and we should not miss
our chance."

Graduate student Sergey Prokushkin and Marina Shmakova, a research associate
at the Stanford Linear Accelerator Center, also contributed to the studies.
Research was supported with grants from the National Science Foundation, the
Templeton Foundation, the U.S. Department of Energy and the Stanford
Graduate Fellowships program.

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