PLEASE NOTE:


*

CCNet 122/2001 - 20 November 2001: LEONIDS FALL WELL BELOW EXPECTATIONS
=======================================================================


"This year's Leonids were marked from excellent lunar conditions.
The weather was also very friendly to most of the observers around the
world. The strongest peak observed is around 18h20min UT which was
suitably situated for the observers in East Asia and Australia. The
rates during this peak reached more then 2800 meteors per hour. This is well
below the theoretically predicted peak levels which were around 5000
according to Lyytinen/Nissinen/van Flaudern or 8000 in Asher/McNaught's
model."
--Vladimir Krumov, International Meteor Organisation, 20
November 2001


"There was a very similar event [sonic boom] on Friday 16 November
around 10:15 a.m., according to reports from Peterlee to Gateshead in
north-east England. That source was tracked down quickly, largely
because Police Force HQ at Durham had been shaken by the blast, and
contrary to the RAF's quoted denial re the November 13-14 event, it was
indeed determined to have been a military jet going supersonic a short way
out over the North Sea, where a large flight of aircraft were on
exercises. With military air exercises across northern England/southern
Scotland in recent weeks persisting through till at least 23h UT on
some nights, I would not be surprised to discover the November 13-14 event
was down to a military source, possibly somebody exceeding the sound
barrier when they shouldn't have, hence the RAF's negating comment.
I've had no reports of a bright fireball that night so far certainly,
though skies in NE England were at least partly clear up to midnight then
from my own records."
--Alastair McBeath, Society for Popular Astronomy, 20
November 2001


(1) 2001 LEONIDS FALL WELL BELOW EXPECTATIONS
    Vladimir Krumov <vkru@yahoo.com>

(2) LEONIDS: WILD STORM OF SHOOTING STARS SEEN SUNDAY MORNING
    Space.com, 18 November 2001

(3) CALL FOR PAPERS: HOLOCENE IMPACTS AND THEIR EFFECTS
    Benny J Peiser <b.j.peiser@livjm.ac.uk>

(4) EVIDENCE OF MARTIAN LIFE DEALT CRITICAL BLOW
    Arizona State University, 20 November 2001

(5) RESEARCHERS DISPUTE LIFE-ON-MARS REPORT: METEORITE EVIDENCE INADEQUATE
    Houston Chronicle, 19 November 2001

(6) RESEARCHERS SET CRITERIA FOR RECOGNISING EXTRATERRESTRIAL LIFE
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(7) TOOL FOR FIRST COMET ORBITER WILL EXAMINE ESCAPING GASES
    Ron Baalke <baalke@zagami.jpl.nasa.gov>

(8) SEPTEMBER 11 & PROJECT SPACEGUARD
    BBC's Letter from America,

(9) SONIC BOOM OVER SCOTTLAND, NOVEMBER 13-14
    Alastair McBeath <vice_president@imo.net>

(10) THE 2350 BC EVENT(S)
     Mike Baillie <m.baillie@qub.ac.uk>

(11) IMPACT PROBABILITY & PLANETARY DEFENSE
     Worth Crouch <doagain@jps.net>


===============
(1) 2001 LEONIDS FALL WELL BELOW EXPECTATIONS

>From Vladimir Krumov <vkru@yahoo.com>

-----------------------------------------------------------
            International Meteor Organization
                 Meteor Shower Circular

               2 0 0 1    L E O N I D S
-----------------------------------------------------------

This year's Leonids were marked from excellent lunar conditions. The weather
was also very friendly to most of the observers around the world.

The strongest peak observed is around 18h20min UT which was suitably
situated for the observers in East Asia and Australia. The rates during this
peak reached more then 2800 meteors per hour. This is well below the
theoretically predicted peak levels which were around 5000 according to
Lyytinen/Nissinen/van Flaudern or 8000 in Asher/McNaught's model.

As far as the first peak, observed from America, is concerned rates were
between 1000 and 1500 meteors per hour. However there is still not enough
data reported from it especially about the time after 11 UT.

The first activity profile is derived from the observations of 38 observers.
It is aimed to give a general view of the observed shower and no conclusions
can be made on this stage. The following detail analysis will tell us more
about the shower and the dust trail models.

Data of the following observers is included in the preliminary profile. The
countries in brackets show the place where observations were carried out,
not necessarily his home land :
Albert Kong (USA), Andreas Buchman (Germany), Andrzej Skoczewski (Poland),
Antonio Martinez (Venezuela), Brian Shulist (Canada), Camila Bacher (USA),
Carles Pineda Ferre (Spain), Detlef Koschny(Australia), Francisco A.
Rodriguez Ramirez (Spain), Gaurav Rathod (India), Ina Rendtel (Germany),
James Bedient (USA), Jaydeep Belapure (India), Joe Zemder (Australia), Josep
M. Trigo-Rodriguez (Spain), Joseph Zammit (Malta), Kamil Hornoch (Pland),
Ken Hodonsky (USA), Kim Youmans (USA), Marion Rudolph (Germany),Mark Davis
(USA), Martin Galea De Giovanni (Malta), Mayuresh Girish Prabhune (India),
Michael Doyle (USA), Miguel A. Serra (Spain), Mike Linnolt (USA), Rafael
Haag (Brazil), Rainer Arlt (Korea), Robert Lunsford (USA), Shigeo Uchiyama
Japan), Sirko Molau (Korea), Tom Roelandts (China), Tomislav Jurkic
(Croatia), Umberto Mul? Stagno (Tunis), Valentin Velkov (Bulgaria), Werner
Hamelinck (China), Xiaorong Wang (China), Zhou Xingming (China)


_____________________________________
Date Time Sollong Nint Nobs ZHR  +/-
--------------------------------------
18   0100 235.732  23   8    52   4
18   0300 235.816  22   9    80   3
18   0500 235.900  21   8    95   5
18   0630 235.963  11   5   160  10
18   0730 236.005  15   7   200  10
18   0815 236.036  13   5   150  10
18   0845 236.057  15   5   270  15
18   0915 236.078  18   6   430  20
18   0945 236.099  12   6   570  20
18   1015 236.121  17   6   790  25
18   1045 236.142  20   5  1000  25
18   1130 236.173   8   2   400  40
18   1300 236.236  12   2   370  25
18   1430 236.299   9   1   320  20
18   1530 236.341  16   3   490  30
18   1630 236.383  16   3   780  40
18   1700 236.404  16   4  1100  50
18   1730 236.425  18   4  1550  50
18   1800 236.446  20   5  2320  60
18   1820 236.460  28   7  2850  60
18   1840 236.474  32   7  2430  50
18   1900 236.488  21   6  1580  50
18   1920 236.509  18   5  1160  40
18   1940 236.516  17   5  1020  40
18   2000 236.530  17   7   800  30
18   2030 236.551  13   5   470  20
18   2120 236.587  16   5   150  10
18   2220 236.629   7   4   130  10
______________________________________

Calculations are made for population index r=2.0. Nint is the number of
intervals observing intervals in a certain period. Nobs is the number of
different observers in it.

Many thanks to all the observers that have contributed their data. Also to
the favorable weather conditions whish are not so typical for this part of
the year.

Clear Skies,
Vladimir Krumov

==============
(2) LEONIDS: WILD STORM OF SHOOTING STARS SEEN SUNDAY MORNING

>From Space.com, 18 November 2001
http://www.space.com/scienceastronomy/astronomy/leonids_wrap_011118.html

By Robert Roy Britt
Senior Science Writer

Vivid streaks of light, sometimes several at a time, zipped across the early
Sunday morning sky as the 2001 Leonid meteor shower reached a stunning
crescendo. A few of the meteors exploded into dazzling fireballs as
skywatchers in North America and elsewhere witnessed ancient space dust
plunging into Earth's atmosphere and vaporizing.

The event was well documented by scientists, and it will live forever in the
memories of thousands of amateur astronomers and first-time viewers who
braved sometimes chilly weather and fought off sleep.

"It was a fabulous show," said Jim Graham of New York City, who traveled
about 100 miles north to view the Leonids under darker skies. "At one point
we saw six at once, in about a second. Some seemed to have a punctuation
mark at the end, with a little trail that blows up. We saw one that lit up a
big piece of the sky and just exploded at the end."

"It was unbelievable," said Robin Lloyd, who works at the American Museum of
Natural History in New York and watched with Graham and his son. "It was the
most beautiful thing."

It's too soon to say for sure whether the 2001 Leonid meteor shower, which
peaked before dawn, will qualify as a storm as scientists had predicted. But
early indications point to a storm designation. A meteor storm is defined as
a shower that exceeds an hourly rate of 1,000 meteors.

Either way, it was unlike anything seen on Earth since 1966, professionals
and casual observers agreed. And astronomers say it won't be repeated for
nearly a century.

Reports from many locations

Early risers from California to Ohio to Virginia and elsewhere described
similar experiences -- an occasionally wild show with peaks and lull, all
lasting from shortly after midnight until dawn.

Some witnesses described fast-moving meteors, zooming across all parts of
the sky and sometimes leaving smoky trails.

In rural Maryland under fairly dark skies, this reporter counted four
meteors per minute during a five-minute stretch at 4 a.m., but by 5 a.m.
that count grew to more than eight per minute. That equates to an hourly
rate of 480. But many meteors went unseen on a foggy horizon.

A group of scientists reported an hourly rate of 800 shooting stars above
New Mexico. A Texas observer counted dozens in a few seconds -- and did so
several times. Other groups observing in the Southwest reported preliminary
estimates in the neighborhood of 2,000 meteors per hour for a short stretch
of time.

A stronger display was expected in Australia and parts of eastern Asia. One
preliminary report from a group of NASA scientists claimed an hourly rate of
1,250 meteors in Hawaii. One early and rough report from China indicates
rates may have reached 2,000 or more.

Behind the show

The display was the result of space dust vaporizing in Earth's atmosphere.
Most of the shooting stars were created by stuff no larger than sand grains.
The debris is the exhaust of comet Tempel-Tuttle, which orbits the Sun every
33 years. Earth passed through several separate trails of this debris over
the weekend. Some of the trails had been laid down centuries ago.

Four different research groups had predicted when and where various peaks of
activity would occur, and how many meteors per hour would be visible at the
peak time. But meteor shower forecasting is in its infancy. Serious Leonids
forecasts go back to just 1998.

The predictions for North American ranged from 800 meteors per hour to
4,200. In parts of Asia and Australia, a peak hourly rate of 8,000 or more
was expected. The hourly rates were expected to be achieved during short
bursts that would last 30 minutes or less.

The show is not entirely over. Though the peak is past, the Leonids will
wind down through Nov. 21. Each morning until then offers an opportunity to
see some shooting stars, both those associated with the Leonids as well as
others.

This time of year is a busy one for shooting stars in general.

Monday morning observers with dark skies can expect to see up to 35 total
meteors per hour in the Northern Hemisphere and 20 in the Southern
Hemisphere, according to Robert Lunsford of the American Meteor Society.
Unpredictable bursts of Leonid activity could send the rates higher for
short stretches. Similar activity was spotted early Friday and Saturday.

While the Leonids are also visible in Europe and elsewhere, the strong
bursts of activity were confined to a few regions of the globe.

Next year's Leonids are expected to equal or exceed this year's count, but
the show will be largely drowned out by a full Moon.

Satellite threat

Satellite operators have been watching the Leonids with wary eyes. A
fast-moving Leonid meteor can damage or disable a satellite. NASA scientist
and meteor forecaster Bill Cooke said before the shower that there would be
between 1-in-10,000 and 1-in-1,000 chance of at least one satellite being
significantly damaged during the full duration of the shower.

So far, there have been no reports of satellite damage.

Defense officials have said military satellites are more robust than most
and are capable of withstanding an impact. Measures were taken to protect
spy satellites and other spacecraft critical to military operations, but
officials would not say what those precautions were.

Copyright 2001, Space.com

============
(3) CALL FOR PAPERS: HOLOCENE IMPACTS AND THEIR EFFECTS

>From Benny J Peiser <b.j.peiser@livjm.ac.uk>

As part of next year's conference on ENVIRONMENTAL CATASTROPHES AND RECOVERY
IN THE HOLOCENE (see below), I am organising a special afternoon session on
"Holocene extraterrestrial impacts and their effects". This session will
focus on

* environmental effects of small and medium scale hypervelocity impacts
* sub-critical impacts and Holocene impact craters
* tsunami sediments and oceanic impacts
* detecting oceanic and atmospheric impacts in the geological record
* Tunguska and Super-Tunguskas
* cometary dust loading and abrupt climate change
* impacts and the abrupt end of ice ages
* impacts and societal evolution.

Researchers interested in presenting a paper or a poster on Holocene impacts
and their effects are kindly requested to contact me as soon as possible.

Dr Benny Peiser
Liverpool John Moores University
School of Human Sciences
Henry Cotton Campus
Liverpool L3 2JQ
United Kingdom

--
ENVIRONMENTAL CATASTROPHES AND RECOVERY IN THE HOLOCENE
Brunel University, London, U.K. 29th August-2nd September 2002
http://www.brunel.ac.uk/depts/ges/Catastrophes/firstcirc.html

The conference will focus on the inter-disciplinary investigation of past
geological and environmental catastrophes, both natural and anthropogenic,
since the beginning of the Holocene (i.e. 11,500 years B.P.). This excludes,
therefore, the influence of glacial-interglacial cycles.

Three timescales will be considered:

1) The Holocene, when major natural hazards can be identified mainly
from sedimentary records.
2) The last 5000 years, which comprises the period during which the
first written records are available.
3) The last two to three centuries, for which instrumental records are
available.
 
Importantly, the conference will examine how quickly ecosystems and
civilisations are able to recover from catastrophic events.

With the growing recognition that major natural and anthropogenic events can
have abrupt global impacts, this meeting is a timely opportunity to assess
the sensitivity of modern society to extreme environmental threats. The
meeting will be concluded by a session focusing on the prediction and
mitigation of environmental catastrophes, to which delegates from the
private sector (e.g. insurance groups) and the media will be invited.

The meeting will combine an oral programme of major keynote addresses
(mostly by invitation) with an accompanying poster session. Poster papers
will be invited from any interested party with the session providing an
ideal opportunity for young scientists to present the results of recent
research in this field.

An informal post-conference field trip is planned, preliminary details of
which can be found on this web site.

Anticipated achievements of the conference

1) The development of a new multi-disciplinary field
Archaeologists, climatologists, tectonicians, palaeoenvironmentalists,
palynologists, dendochronologists, geologists and historians will
collaborate to find out about ancient catastrophes, their impact, and the
recovery of past ecosystems and societies. We anticipate that this may lead
to the formation of new working groups.
 
2) A high-profile international scientific event
We hope that the conference will be a high-profile, general science event
that will attract both public and media attention.

3) Publication of proceedings in a high quality international journal
A collection of papers presented at the meeting will be edited by the
convenors and published as a special issue of a major international
geoscience journal. 'The Holocene' and 'Quaternary International' have
already indicated their interest.

Those interested in participating in the conference should complete and
return the on-line pre-registration form

===========
(4) EVIDENCE OF MARTIAN LIFE DEALT CRITICAL BLOW

>From Arizona State University, 20 November 2001
http://clasdean.la.asu.edu/news/buseck.htm

News Release
Danika Painter
Contact: James Hathaway, 480-965-6375
Hathaway@asu.edu
Embargoed until November 20, 2001

Source: Peter Buseck, 480-965-3945

Image: http://clasdean.la.asu.edu/news/images/buseck/

Evidence of Martian Life Dealt Critical Blow

When, in 1996, a group of NASA researchers presented several lines of
evidence for fossil bacteria in a Martian meteorite, a wave of excitement
passed through the public and the scientific community alike. Of course,
that wave was followed by a storm of controversy.

Five years of scrutiny and debate over the NASA group's claims have since
brought all but one of their arguments unceremoniously back to Earth.
Non-biological processes and contamination could explain the
"bacterium-shaped objects" and organic chemicals found in the meteorite,
other scientists have argued.

Only one line of evidence for bacterial life in the meteorite still stands:
Microscopic crystals of a mineral called magnetite. According to the NASA
scientists, the magnetite crystals found in the meteorite are so
structurally perfect, chemically pure, and have such unique, distinctive
three-dimensional shapes that only bacteria could have produced them, not
any inorganic process. This claim, too, is now being assailed by new data
and criticisms from an Arizona State University research team and their
collaborators.

Peter Buseck, Regent's Professor of geological sciences and professor of
chemistry and biochemistry at ASU, and Martha McCartney, a research
scientist at the ASU Center for Solid State Science, argue that the match
between the meteoritic crystals and those in bacteria is at best ambiguous.
At worst, they say, the data used in the NASA group's analysis is mistaken.

In their paper, "Magnetite Morphology and Life on Mars," published November
20, 2001, in the Proceedings of the National Academy of Sciences, Buseck and
his co-authors assert that the evidence for bacterial magnetite crystals on
the Martian meteorite is inadequate. In doing so, they may have cut the
Martian meteorite's last tenuous hold on life.

The magnetite crystals in the meteorite are tiny, even by an electron
microscopist's standards, at only 40 to 100 billionths of a meter wide. And
there's the rub. The technology necessary to accurately describe the
three-dimensional shape of such small crystals has become available only in
the last few years, and has not yet been used to study the magnetite grains
in the meteorite. Therefore, says Buseck, it is too early to say for sure
what the exact shapes of the meteoritic crystals are, let alone whether they
provide identical matches to those in bacteria.

The only kind of microscope powerful enough to produce clear images of such
small crystals is a transmission electron microscope, or TEM. By using a
beam of electrons rather than a beam of light to view the sample, the TEM
allows researchers to see objects smaller than one billionth of a meter
wide. But a TEM sees only in two dimensions. It generates a spectacular
silhouette image of the sample, but conveys little about its thickness.

An accurate description of the crystals' complex three-dimensional shapes
requires that they be examined from a variety of perspectives.
Discriminating between their flat facets and tapered edges is a particular
challenge - when viewed in profile, the two are indistinguishable straight
edges. Only by tilting each crystal at dozens of angles can scientists
unequivocally identify their three-dimensional shapes, says Buseck.

At the time of the NASA group's study, the tilting experiments could be done
only by hand, with great technical difficulty. "It's a lot of work and it's
not very precise," says McCartney. The NASA group used this approach to
create images of the magnetite crystals from both the meteorite and from one
strain of bacteria.

Since then, scientists studying the three-dimensional shapes of crystals
have upgraded TEM technology and merged it with computer technology. "The
microscope stages and beam shifts and focuses have come under computer
control, which makes the experiments much more doable" and more precise,
says McCartney.

Only two laboratories, Buseck and McCartney's and that of their co-authors
in Cambridge, have applied the new technology to study magnetite crystal
shapes. Using these new developments, they have reexamined the evidence
described in the NASA team's study.

"The shape [the NASA group] came up with disagreed with what we thought the
shape was," says McCartney. This difference calls into question whether the
shapes of the meteoritic crystals are accurately known and whether the claim
of an exact match - the only remaining evidence for bacterial life on the
meteorite - is accurate.

Buseck's team also criticizes several other underpinnings of the Martian
life claim. The NASA group selected only 27 percent of all the magnetite
crystals present in the Martian meteorite for comparison with bacterial
crystals. The Buseck group implicitly questions both the objectivity of
their selection and the effect of such a limited comparison on their
conclusions.

Further, Buseck and McCartney's team demonstrates that the shapes of
bacterial magnetite grains vary more than scientists had previously thought.
The shapes and sizes differ among bacterial strains and even within
individual bacteria. That expanded variety makes it more likely that
bacterial and meteoritic magnetite grains could appear to match by simple
chance.

Lacking sufficiently precise data and resting on a restricted analysis, the
NASA team's claims must be considered best guesses, Buseck and his
co-authors argue.

However, they have not eliminated the possibility that the Martian crystals
could have a biological origin. With more advanced technology now at their
disposal, Buseck and his collaborators plan more conclusive studies of the
magnetite crystals from both the meteorite and several strains of
terrestrial bacteria.

"We will look at them in far greater detail than others have been able to do
before," says Buseck.

Buseck and McCartney's co-authors on the paper are Rafal Dunin-Borkowski,
Paul Midgley, Matthew Weyland (all of Cambridge University, England),
Bertrand Devouard (of Blaise Pascal University, France), Richard Frankel (of
California Polytechnic State University), and Mihály Pósfai (of the
University of Veszprém, Hungary).

============
(5) RESEARCHERS DISPUTE LIFE-ON-MARS REPORT: METEORITE EVIDENCE INADEQUATE

>From Houston Chronicle, 19 November 2001
http://www.chron.com/cs/CDA/story.hts/nation/1138620

By PAUL RECER
Associated Press

WASHINGTON -- A group of researchers say NASA scientists have failed to
prove their contention that a Mars meteorite contains evidence of ancient
microbial life on the Red Planet.

A group led by Peter R. Buseck of Arizona State University said that the
NASA researchers have inadequate evidence showing that tiny crystalline
structures in Mars meteorite ALH84001 were formed by bacteria billions of
years ago as the rock was sitting on the Martian surface.

A study with Buseck as the first author appears today in the Proceedings of
the National Academy of Sciences.

Buseck said that NASA-supported researchers claimed in February that
crystals found in the meteorite are identical to crystals formed on Earth by
bacteria.

The material, known as magnetite, is formed by some bacteria that live on
the bottom of lakes.

The magnetic crystals act as a sort of compass to allow the bacteria to
orient themselves as they move along the lake bottom.

Buseck said there was inadequate similarity between Earthly magnetite and
that found in the Mars meteorite to prove that the material was formed by a
living organism.

"We find that there is much more uncertainty than they seem to believe,"
said Buseck, referring to the NASA researchers.

The Arizona State researcher said there are computer-driven electron
microscope techniques that can be used to determine if the NASA researchers
are correct. He said he plans to do such a study.

Everett Gibson, a NASA researcher who was among the group that first
proposed that ALH840001 contained evidence of life, said that Buseck has not
even looked at the Mars meteorite.

"How can he draw this conclusion without seeing the material?" Gibson asked.

Gibson said that other researchers have found evidence that supports the
NASA group.

In 1996, Gibson and some other NASA-supported researchers announced that
they had found evidence in ALH84001 of life -- microscopic fossils that
could have been bacteria, and carbon chemicals that are linked to life
processes.

They suggested that the bacteria lived on the Red Planet billions of years
ago, when Mars had water and warmer temperatures, and that microbes left
evidence inside the Mars rock.

ALH84001 is thought to have formed on Mars about 4.6 billion years ago and
is the oldest of 16 meteorites found on Earth that have been identified
chemically as coming from Mars.

Scientists believe that an asteroid smashed into Mars 13 million to 16
million years ago and catapulted into orbit a chunk of Mars that contained
ALH84001.

The Mars rock wandered in space for millions of years and finally fell to
Earth about 13,000 years ago. It was found in Antarctica in 1984.

Gibson said that other scientists have found evidence that supports the
findings of his team.

"Our group feels more strongly about our hypothesis now than we did in
1996," he said.

Copyright 2001, Reuters

===========
(6) RESEARCHERS SET CRITERIA FOR RECOGNISING EXTRATERRESTRIAL LIFE

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


Office of Media Relations and Public Information
Arizona State University
Tempe, Arizona

Contact: 
James Hathaway, jim.hathaway@asu.edu, (480) 965-6375

Source:
Peter Buseck, 480-965-3945

November 15, 2001

ASU researchers set criteria for recognizing extraterrestrial life

For as long as people have gazed at the night sky, they have wondered if
neighboring planets could be populated by living things. In fact, recent
explorations of our solar system have relayed several enticing hints that
the life-supporting conditions on Earth may not be so unique.
 
Evidence for water and organic compounds on Mars and Europa has
astrobiologists seriously pursuing the possibility that primitive life once
existed on other planets and moons. As they gear up for the real acid test
-- collecting samples from these distant bodies to examine them directly for
evidence of life -- they are tackling nothing less profound than the origins
of life in the universe.
 
But this pursuit is nagged by an uncertainty: We have never seen our
extraterrestrial cousins before. How will we recognize them if we meet face
to face? Peter Buseck and Martha McCartney, new members of ASU's arm of the
NASA Astrobiology Institute, are among many scientists who
predict the best clues are to be found in lowly bacteria.
 
Buseck, Regents Professor of geological sciences and professor of chemistry
and biochemistry at ASU, and McCartney, a research scientist at ASU's Center
for Solid State Science, were recently funded by NASA to help develop
reliable criteria for identifying traces of life, or "biomarkers," for use
during future astrobiology missions.
 
Study of organisms from Earth, Buseck and McCartney argue, is the most
promising way to start. After all, Earthly life is the only life we know,
making it our one reference point in judging whether extraterrestrial life
exists. Therefore, Buseck reasons, "if you find something in
extraterrestrial samples that resembles life on Earth then it's reasonable
to think that you have found traces of life" on other planets.
 
Because astrobiologists expect extraterrestrial life, if it exists, to be
simple, terrestrial bacteria are getting top billing as model Martians.
Bacteria are single-celled organisms, among the most primitive life forms on
Earth. But the hunt for ancient bacteria presents some special challenges.
Bacteria, all soft parts and no bones, do not usually leave any traces in
the rock record, making their presence hard to prove. To unequivocally
demonstrate that bacteria were ever present, Buseck stresses that "you need
some sort of biomarker, some sort of remainder." Preferably, that biomarker
should be a durable material, such as a mineral, that can survive for
billions of years.
 
Just such a long-lasting biomarker may have already been found -- in a NASA
scientist team's 1996 claim of fossil bacteria in a 4.5 billion-year-old
Martian meteorite, perhaps the most stunning evidence to date of
extraterrestrial life. Not surprisingly, the claim continues to spark heated
controversy. Buseck and McCartney aim to moderate the debate by putting the
Martian life hypothesis to a very thorough test.
 
The group of scientists originally studying the now-renowned meteorite --
known as ALH84001 -- presented a slew of findings, including organic
chemicals and "bacterium-shaped objects," that
collectively cried "life." Since then, intense scrutiny by other researchers
has shown that most of that evidence could have resulted from non-biological
processes or artifacts introduced during study of the meteorite.
 
Only one of the original findings is still thought to be a unique indicator
of life: Crystals of an iron-based mineral called magnetite. The crystals
found in the meteorite are striking because magnetite grains with similar
size, purity, and structural perfection previously have been seen only in
bacteria found on Earth. According to the NASA group's report, no inorganic
process could have produced the meteoritic crystals. Only so-called
"magnetotactic" bacteria, which form the magnetite grains through a
controlled process, can generate these particular shapes.
 
Magnetotactic bacteria, common in aquatic and marine habitats, produce and
carry the magnetic crystals in a chain. The chain, which looks like a faux
backbone under a microscope, acts like a compass as the bacterium swims
along Earth's magnetic field lines.
 
These crystals are at the center of Buseck and McCartney's planned work. If
bacterial synthesis is the single possible explanation for the magnetite
grains found in ALH84001, they could be the one clear indication that life
ever existed outside Earth. But, Buseck worries, if no major holes have yet
been punched in this argument, that may be because it has not been examined
closely enough.
 
And when Buseck says "closely," he means it quite literally. "These crystals
are at the limit of what one can see, even with powerful electron
microscopes," he says.
 
At 40 to 100 billionths of a meter wide, magnetite nanocrystals have evaded
clear three-dimensional imaging. That's a problem for the hypothesis of life
on Mars, which now hinges on precise matching of the complex shapes of the
magnetite crystals from ALH84001 and from
magnetotactic bacteria.
 
"There are questions about how well we know the shapes of these tiny
crystals and how secure the identity is between those in the meteorites and
those in the bacteria," says Buseck.
 
To be able to match the crystals from the two sources with confidence,
Buseck says astrobiologists must first fulfill four clear objectives. "What
we need to do is determine the shapes in the meteorites with high accuracy,
determine the shapes of the crystals in bacteria with comparable accuracy,
demonstrate their identity, and then somehow determine that there are no
other ways of forming such crystals. Then we'd have a tight case."

Of these four steps, Buseck and McCartney intend to test the first three.
They are studying the shapes, chemical composition, and magnetic properties
of both the meteoritic and bacterial magnetite grains in unprecedented
detail. New developments in transmission electron
microscopy, a technique in which samples are viewed with a beam of electrons
rather than a beam of light, have only recently made such precise study of
crystal shapes possible.
 
Using the recently improved techniques, the team will generate dozens of
two-dimensional images taken from different angles as well as
three-dimensional holograms of each magnetite grain. The resolution of their
images will be in the range of hundreds of trillionths of a meter.
 
In these efforts, Buseck and McCartney plan to continue ongoing
collaborations with fellow scientists Dennis Bazylinski (of Iowa State
University), Richard Frankel (of the California Polytechnic State
University), Rafal Dunin-Borkowski, (of Cambridge University, England), and
Mihály Pósfai (of the University of Veszprém, Hungary).
 
Their work will provide improved data and criteria for use in evaluating
whether other magnetite grains, from meteorites or from samples collected in
outer space, have a biological origin. Of course, ALH84001 will be the first
Martian rock subjected to Buseck and McCartney's uncompromising analysis.

===============
(7) TOOL FOR FIRST COMET ORBITER WILL EXAMINE ESCAPING GASES

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


MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov

Contact: Martha J. Heil  (818) 354-0850

FOR IMMEDIATE RELEASE                     November 19, 2001

TOOL FOR FIRST COMET ORBITER WILL EXAMINE ESCAPING GASES

A lightweight NASA instrument from California has arrived in the
Netherlands, one step closer in its journey to examine how gases escape from
the nucleus of a comet.

The Microwave Instrument for the Rosetta Orbiter is one of 17 instruments
that will fly aboard the European Space Agency's major mission to a comet.
Rosetta will be the first spacecraft to orbit a comet, and the microwave
instrument will be the first of its type to be sent to any solar system
object other than Earth.

"We'll look at the abundance of the gases, their temperatures, the speed at
which they're coming off, and the temperature of the comet's nucleus," said
Dr. Margaret Frerking, the microwave instrument's project manager at NASA's
Jet Propulsion Laboratory, Pasadena, Calif.

The JPL-built device was incorporated into the main spacecraft structure in
Alenia, Italy, and arrived in Noordwjik, Netherlands, to begin a series of
tests by the European Space Agency. The next step in its journey is its path
to Kourou, French Guinea, for its January 2003 launch into space. Rosetta
will swing near Earth and two large asteroids before reaching its chosen
dance partner, Comet Wirtanen, on Nov. 28, 2011. At that point in Wirtanen's
5.5-year orbit, the comet will be at about as far from the Sun as Jupiter
and five times as far from the Sun as Earth.

Rosetta will drop a lander onto Wirtanen's nucleus, and the orbiter will
circle the comet at distances as close as 2 kilometers (1.2 miles).

>From the orbiter, the microwave instrument will monitor how the release of
vapors from the comet's icy nucleus changes as Wirtanen moves closer to the
Sun. Gases and dust escaping
from the surface of a comet form a cloud-like "coma" around the nucleus and
a tail pointed away from the Sun.
 
"The spacecraft will remain in orbit around Wirtanen for 20 months as the
comet moves in from Jupiter's distance from the Sun to about Earth's
distance," said JPL's Dr. Samuel Gulkis, principal investigator for the
instrument. "During that time, the nucleus will warm significantly, and
we'll be able to watch the whole process as the comet evolves from an
inactive iceball to having a fully developed coma."

The instruments onboard the orbiter will include a camera to study surface
details, a microscope to analyze dust grains coming off the nucleus,
spectrometers to examine surface and coma materials in various wavelengths,
and an experiment to probe the comet's interior with radio waves.

The microwave instrument is a very high frequency radio spectrometer,
weighing about 20 kilograms (44 pounds). It is designed for studying water,
carbon dioxide, ammonia and methanol gases, four of the most abundant gases
from comets. The device is sensitive to slight differences in emission
wavelengths from those gases, allowing it to measure the quantities coming
off the nucleus, along with their temperatures and speeds.

"We want to get a good estimate of the amount of mass being lost by the
comet so we can play that backward to get at what the comet was like shortly
after it was formed," Gulkis said. That will help pin down ideas about how
comets and planets were produced during the infancy of our solar system.

The microwave instrument will also be able to measure both the surface
temperature of the nucleus and the temperature just below the surface. "That
temperature difference will tell us about the insulating properties of the
surface and help us understand the thermal physics of what's going on inside
the nucleus," Gulkis said.

As Rosetta passes the stony asteroid Otawara and the carbon-rich asteroid
Siwa on its roundabout route to Wirtanen, the microwave instrument will
examine thermal properties of those minor planets' surfaces and check
whether they have any permafrost layer leaking small quantities of water
vapor into space.

Online information is available about Rosetta at http://sci.esa.int/rosetta
and about the microwave instrument at http://mirowww.jpl.nasa.gov . JPL, a
division of the California Institute of Technology in Pasadena, manages the
instrument for NASA's Office of Space Science, Washington,
D.C.

==============
(8) SEPTEMBER 11 & PROJECT SPACEGUARD

>From the BBC's Letter from America,
http://news.bbc.co.uk/hi/english/world/letter_from_america/newsid_1664000/1664088.stm

The following is a quotation from, you'll be mightily relieved to hear, a
work of fiction written 28 years ago. It came in a letter from a faraway
friend. Fasten your seat belts.

At 9.46 on the morning of September 11th in the exceptionally
beautiful summer of 2007, most of the inhabitants of Europe saw a
dazzling fireball appear in the eastern sky. Within seconds it was
brighter than the Sun.

As it moved across the heavens, somewhere above Austria, it began to
disintegrate, producing a series of concussions so violent that more than
a million people had their hearing permanently damaged. They were the
lucky ones.

Moving at 50 kilometres a second, a thousand tons of rock and metal
impacted on the plains of northern Italy destroying in a few flaming
moments the labour of centuries. The cities of Padua and Verona were
wiped from the face of the Earth and the last glories of Venice sank
forever beneath the sea as the waters of the Adriatic came thundering
landward after the hammer blow from space.

Six hundred thousand people died. After the initial shock mankind
reacted with a determination that no earlier age could have shown. So began
Project Space Guard.

Well, both the dreadful event and the determination to prevent its ever
happening again are recounted in a fantasy written by Arthur C Clarke in
1973 - a novel called Rendezvous With Rama.

Sooner or later - in this case it was rather surprisingly later - somebody
in Congress came to realise that whereas the meteorites of 1908 and 1947 had
fallen in uninhabited wilderness by the end of the present century there
won't be such spaces safe for celestial target practice.

Anyway 20 years later Congress took Dr, now Sir, Arthur C Clarke seriously
and urged Nasa to set up a workshop - humble word to describe the awesome
project of inventing telescopes that could detect asteroids at 200 million
kilometres away, become aware of them a decade in advance and acquire the
technology to deflect their trajectories.

The Nasa workshop exists and with due credit takes its name from Clarke's
fantasy: The Space Guard Project.

I thought it would be refreshing, for a change, to relieve the horrors of
what we now consider a manmade catastrophe to consider what some other
bodies in the Universe have in store for us, or for our grandchildren, and
to know that something positive is being done about it.

This fascinating dollop of consolation came to me the other morning in a
letter from my old friend in Sri Lanka who, for his part, says he's
wondering still how he got the Space Guard idea but is even more "still
getting over the extraordinary coincidence that in my novel the meteorite
that destroyed Northern Italy fell on 11 September".

Well I am the least mystical of men but a complementary even odder
coincidence is the fact that just when old Arthur Clarke was pondering his
choice, 28 years ago, of September 11 as doomsday, I was here, a global leap
away, wondering why my immediate reaction to the collapsing of the Twin
Towers was the last day of the battle of the Marne, September 11, 1914.

There must be something to coincidences beyond coincidence. And I leave it
to be figured out by more clairvoyant or spiritual types......

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

(9) SONIC BOOM OVER SCOTTLAND, NOVEMBER 13-14

>From Alastair McBeath <vice_president@imo.net>

Dear Benny,

I've just scanned the press reports on this sonic boom in CCNet 120/2001.
There was a very similar event on Friday 16 November around 10:15 a.m.,
according to reports from Peterlee to Gateshead in north-east England. That
source was tracked down quickly, largely because Police Force HQ at Durham
had been shaken by the blast, and contrary to the RAF's quoted denial re the
November 13-14 event, it was indeed determined to have been a military jet
going supersonic a short way out over the North Sea, where a large flight of
aircraft were on exercises. With military air exercises across northern
England/southern Scotland in recent weeks persisting through till at least
23h UT on some nights, I would not be surprised to discover the November
13-14 event was down to a military source, possibly somebody exceeding the
sound barrier when they shouldn't have, hence the RAF's negating comment.
I've had no reports of a bright fireball that night so far certainly, though
skies in NE England were at least partly clear up to midnight then from my
own records.

Best wishes,

Alastair McBeath,
Society for Popular Astronomy: Meteor Director

==========
(10) THE 2350 BC EVENT(S)

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

Benny,

can I contribute a sentence on the 2350 BC picture. I've previously noted
that the Irish trees see an unusual inundation event 2354-2345 BC. Some time
ago I noted that Ussher's date for the Flood was 2349 BC. I didn't then
appreciate that Newton and Halley both believed that the Flood of 2349 BC
(using Ussher's date) was caused by a comet. So Newton presumably had access
to some of the lore which is now being brought together with respect to this
event (see Schechner Genuth, S. 1997 Comets, Popular Culture, and the Birth of Modern
Cosmology. Princeton University Press). One gets a feeling that this event is likely to
'come together' even before we manage to sort out AD 540.

Mike Baillie

=============
(11) IMPACT PROBABILITY & PLANETARY DEFENSE

>From Worth Crouch <doagain@jps.net>

Dear Dr. Peiser:

In the CCNet articles of 16 November 2001 I was particularly intrigued by
(13) CHAOS AND STABILITY OF THE SOLAR SYSTEM and (7) GRAVITATIONAL EFFECTS
OF EARTH IN OPTIMIZING DELTA V FOR DEFLECTING EARTH-CROSSING ASTEROIDS. Both
reinforce the ideas in the COSMIC CATASTROPHE SURVIVAL STRATEGY published by
CCNet January 22, 2001 where it started, "Consequently, since it has not
been determined how many asteroids are in the Apollo Belt and because comet
paths are not exact it seems just a matter of time and a mathematically
chaotic chance before the Earth will be impacted by an asteroid or comet
capable of catastrophic devastation."

In the past few years many discoveries of previous possible and probable
comet/asteroid Earth impacts have come to light. Just one possible impact
occurred in Iraq around 2350 B.C. and that may have caused a newly found
2-mile-wide crater. Interestingly at that time one or more catastrophic
events wiped out several advanced societies in Asia and Africa. Partly
because of discoveries like that in Iraq the ability to predict the
probability of cosmic Earth impacts seem to be even less accurate than ever,
because impact numbers are constantly changing upward, and thus are actually
unknown. Ongoing impact discoveries reinforce my reasonable doubt that
probabilities and predictions of cosmic catastrophes have very much
validity, other than collisions will occur. Article (13) also reinforces my
belief that randomness in space is more than just a deficiency of our
knowledge but an understatement. The emerging idea that the orbits of small
members of the solar system-asteroids, comets, and interplanetary dust-are
chaotic and undergo large changes through geologic time indicate that those
mathematically chaotic orbits are not yet predictable. Furthermore, article
(7) provides one reason causing the orbits of asteroids to be chaotic when
the article states, "Generally speaking, the increments in the minimum
DeltaV due to the gravitational effects of the Earth are large (by as much
as 60%) for near-Earth asteroids, and the errors diminish for orbits with
large eccentricities (e > 0.7)." Also as reported from Space.com, 19 October
2001 - ASTEROID DISCOVERIES MAY OUTPACE ABILITY TO ASSESS THREAT TO EARTH,
thus the continuing discovery of ever more Earth threatening asteroids
compound the difficulty of predicting collisions with the Earth using
probabilities. Finally since Earth threatening comets can emerge from the
Oort cloud at any time it is even more evident that predicting the
probability of a comet collision with the Earth has very little reliability,
other than a collision will occur.

Unfortunately predicting the next cosmic collision with the Earth using
probabilities based on faulty data is like predicting nothing at all.
Therefore, we should expect our world to face a comet or asteroid impact at
any time. Believing that we are only impacted every 100,000 or 100,000,000
years gives people and their governments a false since of security,
especially since Siberia was impacted less that 100 years ago.

If it were true our planet continually faces the threat of random cosmic
collisions that could range from terrible to catastrophic this would be the
best argument favoring a planetary defense. Considering the limited impact
data available, and the chaotic condition of the orbits of Earth crossing
objects, I see little reason to delay the development of a comet/asteroid
defense system. It would save our planet from far greater distraction than
has been documented by all historic wars or worldly natural catastrophes.
The evidence indicates that scientists believing otherwise are just hiding
their heads in the sand, and doing a disservice to the human race by
extrapolating nonsense without adequate data.

I would appreciate comments from those believing in collision predictability
based on probability schemes and invite them to document, beyond a
reasonable doubt, the logic of their conclusions with reference to the
evidence in this letter.

Worth F. Crouch (Talako)
Choctaw Society  of Astrobiologists

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