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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