CCNet 135/2000 - 19 December 2000

"Even among enthusiastic sky watchers, the prospect of the annual
Ursid meteor shower rarely provokes more than mild interest. Normally,
the shower's feeble maximum on Dec. 22nd produces no more than a few
shooting stars per hour. It hardly seems worth the trouble to spend a
frigid winter night outdoors just to see a meager half-dozen or so meteors.
But this year could be different. According to NASA scientist Peter
Jenniskens (NASA-Ames SETI Institute) and colleague Esko Lyytinen, our
planet is now heading directly for a dusty debris stream shed by
periodic comet Tuttle, the parent of the Ursids. Meteor rates could soar
to more than 100 per hour next Thursday night and Friday morning when Earth
plows through the stream of meteoroids."
    --NASA News, 18 December 2000

"In his new book 'The Great Maya Droughts,' Gill presents evidence
tracing the societal collapse to a major climate change during that
period. Gill and several other theorists have argued that some past
societies dissolved not because they did anything wrong but because of
natural cataclysms, he said at an American Geophysical Union news conference
yesterday. In archaeological research, 'climate change is beginning to
emerge as a major 'stressor' to prehistoric cultures,' said his
co-panelist, paleoecologist Mark Brenner of the University of Florida."
    --Keay Davidson, San Francisco Chronicle, 17 December 2000

    Andrew Yee <>

    NASA Science News <>

    Andrew Yee <>

    Richardson Gill <RBGill@JBPCO.COM>

    San Fransisco Chronicle, 17 December 2000

    The St Petersburg Times, 19 December 2000

    CBS News, 19 December 2000

    Institute of Radio Astronomy <>

    Andy Smith <>


From Andrew Yee <>

University of California-Berkeley

Robert Sanders, (510) 643-6998,


Mars' patchwork magnetic field acts as array of umbrellas to protect
planet's atmosphere, according to new mapping study by Mars Global Surveyor

By Robert Sanders, Media Relations

Berkeley -- Though Mars lacks a global protective magnetic shield like that
of the Earth, strong localized magnetic fields embedded in the crust appear
to be a significant barrier to erosion of the atmosphere by the solar wind.

This conclusion by a researcher at the University of California, Berkeley,
emerges from a new map of the limits of the planet's ionosphere obtained by
the Mars Global Surveyor spacecraft, which was launched in 1996 and reached
the planet 10 months later. The new data show that where
localized surface magnetic fields are strong, the ionosphere reaches to a
higher altitude, indicating that the solar wind is being kept at bay.

The findings suggest that these crustal fields could have played an
important role in the past evolution of Mars' atmosphere. If, as some Mars
experts think, much of the planet's atmosphere was stripped away by the
solar wind, these maps show where the solar wind did, and continues to do,
the most damage.

"The ionosphere is what shields the densest part of Mars' atmosphere from
being swept away by the solar wind," said David Mitchell, a research
physicist at UC Berkeley's Space Sciences Laboratory who compiled the map
from spacecraft data. "Our data show for the first time that the crustal
magnetic fields are a major factor limiting erosion of the atmosphere in
some regions. These fields are like umbrellas scattered over the surface
protecting the atmosphere."

The map of the ionosphere will be presented by Mitchell and his colleagues
on Saturday (Dec. 16) during a morning poster session at the San Francisco
meeting of the American Geophysical Union.

Mars at one time presumably had an interior dynamo like that of the Earth,
which would have generated a global magnetic field to shield the atmosphere
from the solar wind.

Data reported in 1998 from the same spacecraft indicated that Mars probably
lost its magnetosphere about four billion years ago, at which time the
atmosphere would have felt the full force of the ionized particle sirocco
from the sun. While at one time the planet apparently had an atmosphere
dense enough to allow liquid water to flow on the surface, most of that has
since disappeared.

A crucial finding was that ancient asteroid or comet impacts wiped out part
of the crustal magnetism, and those regions were not subsequently
remagnetized. Because these demagnetized craters are some four billion years
old, the dynamo must have wound down at least that long ago.

"Finding these demagnetized and very ancient crater sites helped us date
when the dynamo turned off, which was a big help, because now we know when,
in our models, to turn on erosion by the solar wind," said Mitchell. "What
I'm doing is trying to determine where you can apply the erosion. So now we
have the when and the where, and we can estimate the how much." 

Though he hopes soon to use this information to estimate how quickly the
Martian atmosphere dissipated over time, "We're not at the stage yet where
we can apply this new information to modeling the atmospheric loss," he

Mitchell's colleagues include Robert P. Lin, professor of physics at UC
Berkeley and director of the Space Sciences Laboratory; Henri Rème of the
Centre d'Etude Spatiale des Rayonnements (CESR) in Toulouse, France; Paul A.
Cloutier of the Department of Physics and Astronomy at Rice University; and
J. E. P. Connerney and Mario Acuña of NASA's Goddard Space Flight Center.

The data were obtained by an electron reflectometer aboard Mars Global
Surveyor, an instrument built at the Space Sciences Laboratory and CESR to
map surface magnetic fields. Mitchell used the instrument to determine when
the spacecraft, orbiting about 400 kilometers above the surface, was inside
the planet's ionosphere or outside in the gale of the solar wind. This is
possible because the energy spectrum of ionospheric electrons is distinctly
different from that of solar wind electrons.

Between February 1999 and April 2000, the spacecraft mapped the position of
the ionopause -- the boundary between the ionosphere and the solar wind. The
final map was an average over this time period and over thousands of orbits,
representing the probability at any given point that the spacecraft was
within or outside the ionosphere.

When he compared this map with a map of the surface magnetic fields obtained
by a magnetometer also aboard the spacecraft, he found that the ionosphere
extended to the highest altitudes over the strong crustal magnetic fields.
Over areas of weak magnetic field, the ionopause rarely reached as high as
the spacecraft orbit, whereas over strong magnetic areas it nearly always
reached the spacecraft at 400 kilometers altitude, and probably extended
hundreds of kilometers higher.

"The correlation is striking," Mitchell said. "When the spacecraft is flying
over the magnetic anomalies, it is almost always in the ionosphere, whereas
when it's over magnetically weak regions, 90 percent of the time it is in
the solar wind."

Mars' crustal magnetic fields themselves are a mystery, because they are
nearly as strong at the surface as the Earth's magnetic field -- a few
tenths of a Gauss, compared to a third of a Gauss on Earth. Plus they are
arrayed in east-west bands of alternating polarity, extending for over 1,000
kilometers north to south like a bar code across the planet's surface.
Scientists still do not know what materials produce this strong field, or
why it occurs in alternating bands.

Mitchell said the crustal fields have been there for four billion years,
fending off the solar wind. Despite this protection over part of the planet,
however, the solar wind is still considered the most likely cause of the
loss of Mars' atmosphere.

The atmosphere today extends hundreds of kilometers into space, where the
solar wind can ionize the atoms and sweep them away. At such high altitudes,
however, the density is very low. The ionosphere, though it does not extend
to such high altitudes, nevertheless protects the densest part of the
atmosphere from this type of erosion.

The magnetic field lines can be pictured as half cylinders lined up side by
side on the surface, oriented east and west. The place where the
half-cylinders touch are areas of strong vertical magnetic field, where
ionized hydrogen and helium of the solar wind are able to funnel down to low
altitudes. The tops of the cylinders are areas of strong horizontal magnetic
field, which acts as an umbrella to shield the underlying atmosphere from
the solar wind.

"These crustal magnetic anomalies form cylindrical magnetic objects that
shield the atmosphere much like the Earth's dipole field does the entire
Earth, except on Mars it is local," he said. "You can see a very interesting
pattern of shielded regions and cusps where the solar wind funnels down in

The study is supported by the National Aeronautics and Space Administration.

NOTE: David Mitchell can be reached at (510) 643-1561 or .

Color maps of the ionosphere and the surface magnetic fields are available
for download,


From NASA Science News <>

NASA Science News for December 18, 2000

The normally meek Ursid meteor shower could surprise sky watchers with a
powerful outburst on Dec 22nd when Earth passes through a dust stream from
periodic comet Tuttle.
Listen to this story (requires RealPlayer)

December 18, 2000 -- Even among enthusiastic sky watchers, the prospect of
the annual Ursid meteor shower rarely provokes more than mild interest.
Normally, the shower's feeble maximum on Dec. 22nd produces no more than a
few shooting stars per hour. It hardly seems worth the trouble to spend a
frigid winter night outdoors just to see a meager half-dozen or so meteors.

But this year could be different.

According to NASA scientist Peter Jenniskens (NASA-Ames SETI Institute) and
colleague Esko Lyytinen, our planet is now heading directly for a dusty
debris stream shed by periodic comet Tuttle, the parent of the Ursids.
Meteor rates could soar to more than 100 per hour next Thursday night and
Friday morning when Earth plows through the stream of meteoroids.

Comet 8P/Tuttle follows a 13.5-year elliptical orbit that stretches from
just inside Earth's orbit at perihelion (closest approach to the Sun) to an
aphelion point (greatest distance from the Sun) between Jupiter and Saturn.

Each time Tuttle swings past the Sun, it leaves behind a new trail of
debris. These narrow, filamentary trails are regions with a high density of
meteoroids. Until they disperse after some centuries, a strong meteor shower
can happen whenever Earth passes through one.

The debris stream that lies ahead was shed by comet Tuttle in the year 1405.
According to Jenniskens and Lyytinen, Earth will pass 0.52 lunar distances
(0.0013 AU) from the center of the stream at 0729 UT (0229 EST) on Dec. 22nd
-- that's the most likely time for a strong Ursid outburst. From beginning
to end, the encounter could last for 3 to 4 hours, says Jenniskens.

A second but weaker flurry of Ursids is possible at 0840 UT (0340 EST) on
Dec. 22nd when Earth crosses a debris stream deposited in 1392. That
filament lies about 3 times farther away than the1405 stream, so meteor
rates will be lower.

Meteor enthusiasts might not wish to place too much confidence in the exact
times of the predicted outbursts -- they could be wrong. Pinpointing the
Ursid debris trails is a new science and observations are still needed to
refine the models. Sky watchers should be alert for outbursts at any time
after local sunset on Thursday, Dec. 21st, and before dawn on Friday, Dec.

To see the Ursids, be sure to dress in warm clothing, then go outside and
look north. Ursid meteors can appear anywhere in the sky, although their
tails will point back toward the shower's radiant near the bright orange
star Kochab in the bowl of the Little Dipper.

Because the radiant is so close to the north celestial pole, Ursid meteors
are practically nonexistent south of the equator. At most northern latitudes
the Ursid radiant will be above the horizon all night long. The likely
timing of the outbursts favors North Americans.

The last known outburst of Ursids happened in Dec. 1993, when comet Tuttle
was nearing perihelion. Robert Lunsford, Secretary General of the
International Meteor Organization, saw a flurry that he estimates would have
produced 75 meteors per hour under ideal observing conditions.

"It is possible that this shower produces a short-lived burst of activity
every December," notes Lunsford. "The Holiday season combined with poor
weather and bitterly cold temperatures at this time of year in the northern
hemisphere may explain why Ursid outbursts are seldom seen."

"Lunsford's outburst occurred at perihelion of the comet," notes Jenniskens.
"As we demonstrated in our recent paper (Possible Ursid Outburst on Dec. 22,
2000) the 1993 event was caused by a widely dispersed dust component that is
dynamically different than the single dust trails we're heading for this

The strongest Ursid outburst on record happened in 1945, when European
observers saw 120 meteors per hour. The shower was mostly ignored by sky
watchers in the 50's, 60's and 70's, but then in December 1986 observers
spotted another flurry of 90 per hour. Both outbursts, in '45 and '86, came
approximately six years after comet Tuttle had passed perihelion.

Jenniskens and Lyytinen believe they have an explanation for the curious
six-year lag. Many of comet Tuttle's debris particles are dispersed by
Jupiter's powerful gravity when they pass close to the orbit of the giant
planet. But some are in a 12:14 orbital resonance with Jupiter; Jupiter
completes fourteen orbits around the Sun in the same time it takes the
meteoroids to complete twelve. The resonance prevents disturbing close

"Basically, when these resonant meteoroids pass Jupiter's orbit, the planet
is never there," explains Jenniskens. "So, the particles are fairly safe for
a period of time. The stream as a whole can then be gently nudged [by
planetary perturbations] until the meteoroids become Earth-crossers. That
takes 6 centuries. Gradually the meteoroids fall behind the comet because
they move in a wider orbit than the comet does. The lag accumulates and,
after 6 centuries, it adds up to about 6 years."

This year's Ursid meteor shower comes 6.5 years after comet Tuttle last
reached perihelion in mid-1994, substantially increasing the odds of an
outburst later this week.

Since astronomer William Denning first noticed the Ursids around the turn of
the century, there have been plenty of Decembers falling six years after a
perihelion of comet Tuttle when no one saw anything extraordinary. Is that
because meteor watchers tend to congregate by a warm fireplace on Dec. 22nd,
oblivious to the rain of shooting stars outside? Or, are the Ursids simply
unpredictable -- powerful one year and meager the next?

That's what some astronomers are longing to find out and they may have their
answer on Friday!

Stay tuned to for updates about the Ursid meteor shower.
Readers can learn more about the Ursid debris streams in the Dec. 10, 2000,
issue of WGN, the Journal of the International Meteor Organization, in the
paper "Possible Ursid Outburst on Dec. 22, 2000" by Jenniskens and Lyytinen.


From Andrew Yee <>

ESA Science News


ESA SCIENCE communication Service:
+31 71 5653223

Press Contact during the conference 'The Promise of FIRST':
Monica Salomone (+34 649 934887)

15 Dec 2000

ESA's 'Herschel' will shed light on the mysterious transneptunian objects

There are still quite a lot of unsolved mysteries in our neighbourhood, the
Solar System. Astronomers know very little, for instance, about the
so-called 'transneptunian objects': a ring of asteroid-type bodies located
beyond planet Neptune. Dutch astronomer Gerald Kuiper predicted the
existence of this 'belt' fifty years ago -- it is therefore named the
'Kuiper belt' -- but the first detection of one of its constituent bodies
only happened in 1992. Further surveys have provided an estimate of how many
objects are actually there: possibly 10,000 bodies with a diameter larger
than 300 kilometres, and maybe three million larger than 30 kilometres in
diameter. Only 300 of them have been observed so far. The list of pending
questions about them is very long: what's their precise origin and
composition? Which of the comets that periodically visit the Earth are
'Kuiper objects'? ESA's next infrared space telescope, the Herschel Space
Observatory -- formerly called 'FIRST' -- will help to provide the answers,
astronomers gathered in Toledo (Spain) said yesterday.

Large infrared telescopes are the only ones able to give direct information
about the size and chemical composition of the Kuiper belt objects. The new
generation of ground-based giant infrared telescopes are now starting their
study, but the Earth's atmosphere blocks most of the infrared light from
astronomical objects and therefore a large infrared space telescope, such as
ESA's 'Herschel', is needed. 'Herschel' will be launched in February 2007;
more than 200 astronomers from all over the world are gathered this week in
Toledo to discuss its 'scientific agenda'.

"The study of the transneptunian objects will give us many clues to
understand how the Solar System was formed", said Solar System expert
Emmanuel Lellouch (Observatoire de Paris-Meudon, France). "Now we know very
little about them".

Astronomers think these objects are probably like comets: an aggregate of
dust grains mixed with ices -- their surfaces are only heated to minus 230
degrees Celsius by the very feeble distant Sun.

In the Solar System there are three 'reservoirs' of minor bodies: the 'Main
belt' or 'asteroid belt', between Mars and Jupiter; the Kuiper belt; and the
'Oort Cloud' surrounding the whole Solar System.

The comets that 'visit' the Earth for the first time come from the Oort
Cloud, which was made out of left-over material after the formation of the
gaseous planets -- Jupiter, Saturn, Neptune and Uranus. But the 'periodic'
comets -- that come at precise intervals of time -- are originated in the
Kuiper belt. Unlike those coming from the Oort Cloud, these periodic comets
might reflect the original chemical composition of the interstellar cloud
that provided the material to make the whole Solar System (4.6 billion years

"The high sensitivity of the Herschel Space Observatory will allow us to
study in detail these periodic comets, and determine precisely their
chemical composition", said Dominique Bockelée-Morvan from the Observatoire
de Paris-Meudon in France.

Comets are mostly made of water. Finding out the isotopic composition of
this water will help astronomers, among other things, to trace the origin of
water in the Solar System planets, such as our own planet.


* "The Promise of FIRST" workshop
* ESA Science Herschel home page
* FIRST science homepage


[Image 1: ]
Neptune in Primary Colors. Clouds elevated above most of the methane
absorption appear white, while the very highest clouds tend to be yellow-red
as seen in the bright feature at the top of the image.

[Image 2: ]
Another ice-making machine in the Solar System? A Jupiter-like planet
evolves in a disk of gas and dust around a young star, in computer model of
the process devised by Pawel Artymowicz of Stockholm University.

[Image 3: ]
A near-infrared NICMOS image of Saturn.

From Richardson Gill <RBGill@JBPCO.COM>


I thought this article from Sunday's San Francisco Chronicle about a session
I participated in at the AGU meeting might be of interest for the CCNet.

Dick Gill

Richardson B. Gill, PhD
7707 Broadway 11A
San Antonio, Texas 78209-3250
210-822-0305 cell 210-884-0305 fax 210-255-8000


San Francisco Chronicle, 17 December 2000

Effect of Climate on Ancient Societies Debated:
Scientists say shifts may account for demise of civilizations

Keay Davidson, Chronicle Science Writer
Sunday, December 17, 2000
Radical climate change might ravage civilization -- but it won't be the
first time, scientists say. The world is littered with the weedy ruins of
ancient societies like the Mayans -- peoples that once thrived, then
collapsed because they failed to endure sudden climate shifts, researchers
said yesterday at the conference of the American Geophysical Union.

The meeting, which has attracted about 9,000 Earth scientists and space
experts from around the globe, began Friday and continues through Tuesday at
Moscone Center.

The researchers' controversial claim -- which clashes with traditional
historical theories that attribute ancient cultural collapses to political,
economic, military and epidemiological factors -- sounds especially
unsettling this weekend, as numerous American Geophysical Union speakers
report possible omens of global climatic chaos:

-- Sea levels are rising around the world, at least partly because of
"thermal expansion," in which rising temperatures make the ocean expand.

-- In the eastern Pacific, the average wave height is rising and might
eventually threaten North American coastlines and coastal structures.

-- Global warming could destabilize the ice cap over Greenland over the next
century, computer models suggest. The icy continent might entirely melt over
the next 1,000 years, flushing enough water into the ocean to raise the
average sea level by about 20 feet -- enough to submerge parts of San
Francisco and the Bay Area.

Because industrial activity may be changing the climate, modern society
should ponder the fate of the Mayans, whose culture dominated much of
Central America until mysteriously disintegrating between 800 and 900 A.D.,
says anthropologist Richardson B. Gill of San Antonio, Texas.

In his new book "The Great Maya Droughts," Gill presents evidence tracing
the societal collapse to a major climate change during that period.

Gill and several other theorists have argued that some past societies
dissolved not because they did anything wrong but because of natural
cataclysms, he said at an American Geophysical Union news conference

In archaeological research, "climate change is beginning to emerge as a
major 'stressor' to prehistoric cultures," said his co-panelist,
paleoecologist Mark Brenner of the University of Florida, who studies
ancient climate impacts on Mayan and Yucatan cultures.

It's timely research, judging by the news from other American Geophysical
Union sessions.

The immediate climatic threat to Greenland is far worse than that facing the
Antarctic ice sheet, said climate modeler Jonathan M. Gregory of Britain's
famed meteorological office.

For years, the news media and some environmentalists have hyped warnings
that the West Antarctic ice sheet is about to collapse and cause a massive
rise in global sea levels. Such a catastrophe is "now widely held (by
experts) to be rather unlikely" during the coming century, Gregory said

However, as the average global temperature rises in the 21st century, "the
Greenland ice sheet may pass a threshold beyond which it cannot survive,"
Gregory said. He explained that some researchers' computer models show that
a temperature rise of several degrees over the next hundred years could
cause the ice sheet to melt faster than it is replaced by snowfall. By the
year 3000, the ice cap could have melted into the sea, raising the average
sea level by about 20 feet.

Given the forecast's apocalyptic tinge, "I think we should take it
seriously," Gregory said.

©2000 San Francisco Chronicle  

MODERATOR'S NOTE: Sorry folks. But associating the collapse of ancient
civilisations with the current global warming scare is a futile exercise.
If, as has been suggested by many researchers, abrupt climate change was
part of natural causes that may have contributed to the collapse of a number
of ancient societies, these disasters had absolutely nothing to do with
rising temperatures. As far as I am aware - and I know most of the
scientific research and literature on this particular issue - all cases of
societal collapse that have been linked to natural agencies are considered
to be the result of climatic downturns! The real threat to any complex
society is abrupt and persisting cooling and the ensuing lack of adequate
energy and food resources. Significant warming trends, in comparision, while
being sometimes detrimentral to some restricted regions, have always been
benefitial to life in general and human life in particular. During the
Holocene, these warm periods have directly contributed to population growth,
booming trade and economic growth, technological revolutions and rapidly
developing civilisations. In short, if you are really concerned about the
long-term future, stability and prosperity of our global village, start
studying the possible causes of the abrupt and repeated cooling events
during the Holocene - firmly detected in tree rings and ice cores - that may
indeed have led to the decline and fall of a number of highly developed,
ancient societies.
From The St Petersburg Times, 19 December 2000

Scientists Warn of Asteroid Hit

By Kevin O'Flynn

MOSCOW - Russian scientists warned last week that life as we know it could
end as early as Thursday (sic), if any one of the massive asteroids whizzing
through the cosmos should happen to be making a beeline for Earth.

"There is a threat to humanity," said Vadim Simonenko, deputy head of the
Institute of Technical Physics.

Simonenko was among the impressive array of experts at a news conference
with a title straight from a 1950s B-movie: "Asteroid Danger: How to Save
the Earth From Cosmic Catastrophe."

The conference, held Thursday at the House of Journalists, brought together
astronomers, physicists and nuclear experts to urge global cooperation in
saving the world from a devastating asteroid collision that could leave
millions dead or even wipe out civilization entirely.

With asteroids measuring up to 10 kilometers in diameter and traveling at
speeds of up to 20,000 kilometers an hour, Earth would stand little chance
if it was hit by a big one.


From CBS News, 19 December 2000,1597,258014-412,00.shtml

(AP) The rock and dust kicked up by an crashing asteroid 65 million years
ago were not enough to kill the dinosaurs, according to researchers. But the
debris may have sparked a deadly global chemical reaction in the atmosphere.

New studies show the Chicxulub impact crater on the coast of Mexico's
Yucatan Peninsula is smaller than once thought, making dinosaur extinction
difficult to explain completely. Researchers presented those findings Sunday
at the American Geophysical Union's fall meeting.

FULL STORY at,1597,258014-412,00.shtml



From Institute of Radio Astronomy <>

The discussion on panspermia (CCNet 127/2000 - 6 December 2000) ignores the
space debris as interstellar transport. See:

A.V. Arkhipov, Astroinfect Effect: Revised Model // Journal of The British
Interplanetary Society, January 1999, vol. 52, No.1, pp. 37-40.

The computer modelling of the diffusion of space debris into the
interstellar medium and the possibility of interstellar panspermia by
interplanetary pollution are considered. It is
shown that the Earth can be a natural collector of extraterrestrial
non-sterile space debris, which could spontaneously fall on our planet. New
estimation of the panspermia threshold for
interplanetary pollution is obtained at more realistic conditions. The
technogenic interstellar panspermia is quite possible for the new model.

Alexey Arkhipov


From Andy Smith <>

Ho, Ho, Ho....18 Dec CCNet Bulletin outstanding. Here are a few comments.

Reference item 5 in CCN/2000/12/18. Our colleagues, Drs. Simonenko and
Zaitsev, have been doing outstanding work, carrying the Planetary Defense (PD)
Banner. They were major players in organizing, directing and publishing (on the Web) the SPE
94, 96 and 2000 conferences.

In focusing on the 1,000 or so asteroids which are larger than a kilometer,
and discussing the impacts of such monsters, they are joining a large global
group. We disagree with such emphasis, because that asteroid group is such a
small percentage of the threat population (about 1%). We are much, much more
likely to be hit by objects in the 1,2 or 3 size ranges, on our
Asteroid/Comet Emergency (ACE) scale (50-400 meters) and the Tunguska bomb
(which would destroy any metropolitan area in the world) is a Size 1 object.

We appreciate what the Space Shield Foundation is doing, as they try to
develop an open world-forum on PD. They have come a long way but they still
have a lot to do. The recent proceedings are still almost entirely in
Russian. It is still difficult to communicate with them, etc. It looks like
the Space Guard, energy and NASA folks are working with them and we
appreciate all that is resulting.

World Planetary Defense Advocacy

As we see it, there are four major elements in the asteroid/comet emergency
prevention and preparedness picture. They include (1) Understanding the
impact effects and risks, (2)Early-warning, (3)Defense and (4) Civil
emergency preparedness.  The astronomy community is well organized and, as a
result and thanks to LINEAR, we are making major progress toward the
completion of the hunt (from about 12,000 years to complete the 100,000
object search, in the 1980's, down to about 275 years, now).

It is the other areas that are moving too slowly. We see the need to
organize advocacy for planetary defense (and to focus on the other three
areas) and we want to invite all who share that interest to contact us and
join in the formation of such a group. We could formalize it on the Web and
at the ISDC 2000 conference and it would be completely open and

This group could work to improve global coordination and cooperation and
push for more political and public support. We would want to work closely
with all of the present organizations and we would fully use and support the

Study Collaboration

Another big benefit of the CCNet is that it permits informal study efforts
to develop and work. We now have a lively little group looking at the
inhalation complications of asteroid impact (to include the production of
toxics) and we found Item 1, in CCN2000/12/18, especially interesting.

Another nice little dialogue has started on the 830 AD event.

These activities are all so constructive and they continue to show the value
of the Net. Thanks Benny and best wishes.


Andy Smith

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