PLEASE NOTE:


*

CCNet, 45/2000 - 6 April 2000
-----------------------------


     "Nearly none of the known near-earth objects have any chance of
     hitting the earth, and there are just two or three such objects
     that researchers can't dismiss yet, said Marsden. What happens in
     most cases is that the probability of a collision goes to zero as
     more is learned about an object's orbit, composition and other
     characteristics, he said. [...] Still, a catastrophic collision is
     possible, Marsden said. A massive meteor collision is believed to
     be linked to the extinction of the dinosaurs, he said. ‘They
     weren't making observations like this so they didn't know what hit
     them.’"
           -- Brian Marsden, 3 April 2000


(1) DEFENDING OUR PLANET
    ABC News, 3 April 200

(2) BOULDERS ON EROS
    Ron Baalke <baalke@jpl.nasa.gov>

(3) ULYSSES, COMET SPOTTER
    ESA <sciweb@estec.esa.nl>

(4) ULYSSES'S SURPRISE TRIP THROUGH COMET'S TAIL PUTS HYAKUTAKE
    IN RECORD BOOKS
    Jacqueline Mitton <aco01@dial.pipex.com>

(5) COSMIC HERETICS GET A HEARING: DISCOVERY CHANNEL PLANS  
    DOCUMENTARY ON PANSPERMIA & PERIODIC IMPACTS
    Iana Porter <Inewpony@aol.com>

(6) BALLOONING TO MARS
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(7) ASTROBIOLOGY FIELD DRAWS RESEARCHERS
    Space.com, 5 April 2000

(8) MARTIAN MAGNETIC FIELD AND ALH84001
    Everett Gibson <everett.k.gibson1@jsc.nasa.gov>

(9) MARTIAN BACTERIAL MAGNETITE
    Oliver Morton <abq72@pop.dial.pipex.com>

(10) METEORITE CONTAMINATION & A NULL HYPOTHESIS
     Michael Paine <mpaine@tpgi.com.au>

(11) DOUBTS ABOUT VOLCANIC CATASTROPHE AD 536
     Steve Zoraster <szoraster@zycor.lgc.com>

(12) SIXTH CENTURY "COMET" VECTOR
     Leroy Ellenberger <c.leroy@rocketmail.com>

(13) AND FINALLY: MEDIA BOO-BOO OF THE DAY
     Jeremy Tatum <UNIVERSE@uvvm.UVic.CA>

===================
(1) DEFENDING OUR PLANET

From ABC News, 3 April 200
http://abcnews.go.com/sections/science/DailyNews/arizonabservatory000403.html

Arizona Observatory Forms Main link In Earth Defense

By Jolyn Okimoto
The Associated Press

FLAGSTAFF, Ariz., April 3 - Science fiction stories are filled with
heroes defending the Earth from collisions with asteroids and comets.
The reality of such a campaign isn't as dramatic as movies portray
them, but no less important to the people involved.

The Near Earth Object Search program at Lowell Observatory is one link
in the Earth's defense chain, with its aim to identify asteroids and comets
approaching our planet.

"We are quite concerned that one could eventually hit the Earth," said
Lowell astronomer Edward "Ted" Bowell.

LONEOS is among five main programs dedicated to the study of near-earth
objects, which is experiencing a golden age due to technological
advancements and growing awareness, said Brian Marsden, the director of
the Minor Planet Center in Cambridge, Mass. The center confirms
astronomical discoveries and serves as an information clearinghouse on
minor planets and near-earth objects.

Comet Spotting Champion

Of the five, Lincoln Near Earth Asteroid Research, or LINEAR, located
at the Massachusetts Institute of Technology, is by far the leader in
the field, Marsden said.

Still, Lowell's program, which operates out of Anderson Mesa about 12
miles southeast of Flagstaff, holds its own, having discovered 29
near-earth objects in the past two years.

While the number may sound small, the following illustrates Bowell's
view that the process is like finding a needle in a haystack: Last
year, LONEOS recorded 276,000 observations, which resulted in 19
discoveries. A new camera installed this month could double the number
of observations this year, program officials say.
    
So far, one of the most successful observers at LONEOS is Bill Ferris,
who has discovered seven comets or asteroids since June 1998. Two of
those comets were named for him. "He's our champion," Bowell said.
That's strong praise for a man whose background is in television, not
astronomy, and coming from Bowell, who has discovered more asteroids
than any other living astronomer.
    
Ferris, 38, downplays his success as a top comet finder. "I'm no better
observer than anyone past or present," he said. "But I certainly have
access to better technology than comet hunters of long ago."

Watching from a Windowless Room

The work of an observer isn't what one might imagine it to be. Ferris
and other LONEOS observers sit in a windowless office - a window would
cause light interference - analyzing computer images generated by a
camera connected to a telescope. They look for movement, since comets
and asteroids move while stars do not.

Observing hours are long in the winter to take advantage of available
darkness, which in Flagstaff is nearly 11+ hours, but they shrink down
to half that in the summer, Ferris said. "We try to observe for every
minute," he said. Ferris said he doesn't mind the hours. He left a
career as a TV producer and director to work in astronomy, which he
said had always been a hobby.

"My love of astronomy led me to Lowell," he said. Ferris said he rarely
thinks about his job as a way of defending the earth from collisions,
but that he's glad to be part of the team keeping an eye out. "If we
were to ever find something like that, we would like to minimize the
loss of life and maybe prevent the event from happening," he said.

Nearly none of the known near-earth objects have any chance of hitting
the earth, and there are just two or three such objects that
researchers can't dismiss yet, said Marsden. What happens in most cases
is that the probability of a collision goes to zero as more is learned
about an object's orbit, composition and other characteristics, he
said.

That's what happened in February when scientists determined that an
asteroid an Italian researcher thought was on a possible
collision-course with Earth will in fact miss by millions of miles. It
was the fifth time in two years that reports of Earth-threatening
asteroids were proven wrong.

Still, a catastrophic collision is possible, Marsden said. A massive
meteor collision is believed to be linked to the extinction of the
dinosaurs, he said. "They weren't making observations like this so they
didn't know what hit them."

Copyright 2000, AP

===============
(2) BOULDERS ON EROS

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

NEAR image of the day for 2000 April 4

http://near.jhuapl.edu/iod/20000404/index.html

Boulders, Boulders, Boulders

One  of the  most  striking features  in NEAR  Shoemaker images of
Eros' surface is the  abundance of very large boulders. This image of
the  southwestern part  of the saddle region, taken March 6, 2000, from
a range of 201 kilometers (125 miles), shows a particularly
boulder-rich part of the surface. Many of the huge rocks are 50  meters
(164 feet) or  more in diameter. They are believed to be fragments of
Eros' native rock, shattered over the  eons  by  formation of  impact 
craters. The impacting projectiles themselves were pulverized by the
impact process and  survive only as fine  debris mixed into the
regolith.
--------------------------------------------------------
Built and managed by The Johns Hopkins University Applied Physics
Laboratory, Laurel, Maryland, NEAR-Shoemaker was the first spacecraft
launched in NASA's Discovery Program of low-cost, small-scale planetary
missions. See the NEAR web site for more details
(http://near.jhuapl.edu).

===============
(3) ULYSSES, COMET SPOTTER

From ESA <sciweb@estec.esa.nl>

Ulysses, the joint ESA/NASA spacecraft, has added comet spotter to its
list of talents.  Two papers published in Nature today report that on
1 May 1996, the spacecraft flew through the tail of comet Hyakutake whose
nucleus was more than 3.5AU  (one AU equals the Sun-Earth distance) away
at the time. "This makes it the longest comet tail ever recorded", says
Geraint Jones from Imperial College, London who is a member of one of the
two instrument teams that made the discovery. 

Full story: http://sci.esa.int/missions/newsitem.cfm?TypeID=13&ContentID=10011

==============
(4) ULYSSES'S SURPRISE TRIP THROUGH COMET'S TAIL PUTS HYAKUTAKE
    IN RECORD BOOKS

From Jacqueline Mitton <aco01@dial.pipex.com>

ROYAL ASTRONOMICAL SOCIETY
PRESS NOTICE

Ref. PN 00/06

ISSUED BY:

Dr Jacqueline Mitton
RAS Press Officer
Office & home phone: Cambridge ((0)1223) 564914
FAX: Cambridge ((0)1223) 572892
E-mail: jmitton@dial.pipex.com


RAS web: www.ras.org.uk/press/press.htm

* * * * * * * * * * * * * * * * * * * * * * * *
CONTACTS FOR THIS RELEASE

Dr. Geraint Jones
Space and Atmospheric Physics Group, The Blackett Laboratory,
Imperial College, London
Email:     g.h.jones@ic.ac.uk
Telephone: +44 (0) 20 7594 7774
Fax:       +44 (0) 20 7594 7772

Dr. Tim Horbury
Astronomy Unit, Queen Mary and Westfield College, London
Email:     t.horbury@qmw.ac.uk
Telephone: +44 (0) 20 7775 3181
Fax:       +44 (0) 20 8983 3522

Prof. Andre Balogh
Space and Atmospheric Physics Group, The Blackett Laboratory,
Imperial College, London
Email:     a.balogh@ic.ac.uk
Telephone: +44 (0) 20 7594 7770
Fax:       +44 (0) 20 7594 7772

WEB PAGE FOR THIS RELEASE
http://www.sp.ph.ic.ac.uk/Ulysses/comet/
(available from 19.00 BST (2.00 p.m. EDT) on April 5)

* * * * * * * * * * * * * * * * * * * * * * * *

ULYSSES'S SURPRISE TRIP THROUGH COMET'S TAIL PUTS HYAKUTAKE IN
RECORD BOOKS

Comet Hyakutake, a bright comet seen by many people in 1996, developed the
longest comet tail ever recorded. At 570 million km (360 million miles) it
beat the previous claimed record of 330 million km (206 million miles) held
by the Great March Comet of 1843. The discovery was made recently, when Dr
Geraint Jones and Professor Andre Balogh of Imperial College, London,
together with Dr Tim Horbury of Queen Mary and Westfield College, London
analysed 1996 data from the Ulysses spacecraft. Their analysis of the
magnetic field data returned from Ulysses on 1 May 1996 led them to conclude
that Ulysses had passed through a comet's tail on that date. They then found
that the tail belonged to Comet Hyakutake. The discovery is reported in the
journal 'Nature' on 6 April 2000.

The joint European Space Agency-NASA spacecraft Ulysses was launched in
1990, and is in an orbit taking it over the poles of the Sun. It makes
continuous measurements of the stream of charged particles called the solar
wind which flows outwards from the Sun past the spacecraft. On 1 May 1996,
Ulysses was 560 million km (347 million miles) from the Sun, when decidedly
unusual things happened to the solar wind. The first odd feature to be
noticed was a dramatic drop in the number of protons at Ulysses, which was
reported in 1998 by another team of scientists led by Dr Pete Riley, then of
the Los Alamos National Laboratory. They mentioned that a comet could
explain some aspects of the odd results.

Comet nuclei are small bodies that were formed when our solar system was
young. They are typically a few kilometres across, and are composed of a
mixture of ice and dust. When their orbits bring them close to the Sun, the
rise in temperature makes them release gas and dust. The tiny dust particles
are pushed away from the Sun by the pressure of sunlight, forming a dust
tail. The gas particles eventually become electrically charged, forming
ions. These ions join the solar wind flowing away from the Sun, forming an
ion (or plasma) tail. When Jones and colleagues looked closely at the data
returned from Ulysses's magnetometer instrument at the time, they realised
that the solar wind's magnetic field lines displayed a herringbone pattern -
a sign that the centre of whatever Ulysses had crossed had been moving
slower than its edges. This is expected at comets, because the comet's ions
slow down the solar wind when near the nucleus. This convinced them that the
event was indeed due to a comet; so they began to search for the comet to
which the tail belonged.

Finding the comet in question was not simply a case of looking for known
comets between the spacecraft and the Sun on May 1 - as Ulysses was so
distant, the solar wind flowing at 750 kilometres per second could take days
to reach the spacecraft. This gave time for the comet to move away from the
Sun-Ulysses line, making it trickier to find. Comet Hyakutake (official
designation C/1996 B2) had given Earth-bound observers a spectacular display
during late March and early April, 1996, when it approached close to the
Earth. Discovered by Japanese amateur astronomer Yuji Hyakutake in January
1996, the comet was at perihelion (its closest point to the Sun) on May 1 -
the day of Ulysses's tail crossing. When Jones looked at where Hyakutake had
been 8 days earlier, on April 23, it turned out that it had indeed been on
the Sun-Ulysses line, and that from that point, it would take 8 days for the
ion tail to be carried to Ulysses. Using the magnetometer data, the team
found that the tail was the right size to belong to Hyakutake, and that it
was parallel to the comet's orbital plane, as expected. The comet had been
identified.

Apart from the great scientific value of an encounter with a fourth comet
(comets Giacobini-Zinner, Halley and Grigg-Skjellerup have been visited by
other spacecraft), several aspects of the tail crossing are particularly
intriguing. The tail's length is most surprising - Hyakutake's tail was over
570 million km (350 million miles) long. This breaks the record for the
longest measured tail, which is generally regarded to have been previously
held by the Great March Comet of 1843, which had a visible tail around 330
million km (205 million miles) long. Had Hyakutake's tail been visible at
the time from the Earth, it would have stretched over 80 degrees across the
sky - a very impressive length for a comet so far away. However, at this
time, it was invisible from Earth because its head was very close to the Sun
in the sky.

Comets' ion tails are generally thought of as pointing almost straight away
from the Sun. The magnetometer data from Ulysses reveal that at the
spacecraft, the tail was definitely not doing this - it was travelling
almost sideways. Jones and colleagues explain this by the comet's rapid
motion around perihelion. Like the jet of water from a lawn sprinkler,
Hyakutake's tail started out pointing away from the Sun. The further it got
from the Sun however, the more it twisted away from the anti-sunward
direction, as a lawn sprinkler spray twists. Ion tails are therefore curved,
especially when comets are around
perihelion. This has implications for some Earth-based comet observations.
"A few weeks before Ulysses's tail crossing, some observers reported tail
lengths for Hyakutake that were much longer than possible if comet tails are
assumed to be straight, and pointing away from the Sun", says Jones. "The
Ulysses magnetic field measurements show that these assumptions aren't
true.", he continued, "Although it can't quite fully account for some of the
longest tail lengths reported in late March and early April 1996,
Hyakutake's tail would have been curved in the correct way around the Earth
for observers to see a tail longer than previously thought possible."

When Ulysses crossed the tail, the comet's head was being observed by the
LASCO coronagraph aboard the SOHO spacecraft, even though it could not be
seen from Earth. "At this time," says Jones, "what was happening at the head
of the comet didn't have any relevance to the tail at Ulysses. If you want
to study the part of the tail crossed by Ulysses, you need to look at images
of Hyakutake obtained around April 23. Unfortunately, few images were
obtained then, as Hyakutake was sinking into twilight as seen from Earth."
Nevertheless, the Ulysses results are providing unique information on the
magnetic structures of ion tails.

The discovery, and identification of the parent comet by Jones and
colleagues are only the beginning of the event's analysis. The study of the
data returned from other Ulysses instruments will undoubtedly lead to a
fuller picture of what happened when a distant spacecraft crossed an
incredibly long tail. In the same issue of 'Nature', colleagues of Jones and
co-workers, led by Professor George Gloeckler of the University of Maryland,
report their independent discovery of cometary ions during the same event
using another instrument aboard the spacecraft.

The research that led to the discovery is supported by the UK Particle
Physics and Astronomy Research Council.

Further background information on the tail crossing, including images and
animations, can be found from 19.00 BST (2.00 p.m. EDT) on April 5, at:

http://www.sp.ph.ic.ac.uk/Ulysses/comet/

=============
(5) COSMIC HERETICS GET A HEARING: DISCOVERY CHANNEL PLANS  
    DOCUMENTARY ON PANSPERMIA & PERIODIC IMPACTS

From Iana Porter <Inewpony@aol.com>
[as posted on the Minor Planet Mailing List]

Dear minor planet enthusiasts and professionals -

I hope it is appropriate for me to post my request on this list:

We are producing a Discovery Channel documentary special on meteors
which is scheduled to air at the end of 2001. We are in the early
research phases and are exploring the following theories as a possible
focus for our program: that asteroids & comets may have originally
brought life to earth, that major extraterrestrial impacts may be
cyclical rather than random (Nemesis theory), and that our moon may
have resulted from the impact of a mars-sized planet with earth. We are
scheduled to begin filming in the next couple of months and continue
over a period of about six months. I am eager to find researchers who
are embarking on fieldwork expeditions or projects to prove or disprove
these ideas, to investigate mysterious geology, or at least to uncover
a piece of the puzzle ( any expeditions to impact craters, to
interesting layers in stratigraphy, meteorite fields, etc?) - or
researchers who are eloquent and outspoken about these theories.  Also,
I welcome any suggestions for other recent and intriguing discoveries
related to asteroids, comets (meteors). Please contact me via email at
inewpony@aol.com if you are involved or may be able to point me in some
interesting directions! I would appreciate any suggestions you can
offer. 

Many thanks for your attention to my inquiry.

Kindest regards,

Iana Porter
Associate Producer
New Pony Productions
PO Box 989
10397 Hills  Road
Mendocino, CA  95460  USA
707/937-9210 tel
707/937-9212 fax
inewpony@aol.com

========================
(6) BALLOONING TO MARS

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

University Relations
University of Arkansas

CONTACT:
Larry Roe, assistant professor of mechanical engineering
(501) 575-3750, lar@engr.uark.edu

Carolyne Garcia, science and research communication officer
(501) 575-5555, cgarcia@comp.uark.edu

FOR RELEASE: APRIL 4, 2000

Ballooning To Mars

FAYETTEVILLE, Ark. -- Every day Larry Roe grapples with questions like:
How do you inflate what does not exist, under unknown conditions, using
unknown materials, for an unknown application? Roe, a mechanical
engineering professor at the University of Arkansas, faces these
problems in his work with NASA and the Jet Propulsion Laboratory to
invent inflation devices for space missions.

"Some people see these questions as insurmountable obstacles," Roe
laughs. "Those kinds of questions can drive them crazy. But to me they
are creative challenges."

Roe's current challenge is designing systems to inflate structures for
near-term space missions that are in various stages of planning. For
near-term missions, Roe's designs are grounded in known engineering
principles and existing hardware. He is looking at structures that
range in size from a baseball to 50 meters (161 feet) across.
Subsequent missions may call for inflatables that are 3 to 5 kilometers
(2 to 3 miles) across.

For missions to Mars or other planets with sufficient atmosphere, Roe
envisions reconnaissance balloons. These small, lightweight devices
could collect and transmit data or carry cameras to provide additional
views of the planet.

A number of inflatable other devices have also been identified for
these missions, according to Roe. These structures include data
collection and communication antennas, solar shields, thermal
radiators, solar concentrators, light sails, landing systems, rover
tires and habitats. Although vastly different in design and purpose,
they all have a common need for some type of inflation gas.

"Currently, devices such as antennas and reflectors are expensive,
heavy and prone to failure," noted Roe. "Inflatable devices can
overcome these obstacles, making space explorations more reliable and
affordable."

Inflatable structures are classified according to the type of inflation
they require, regardless of their size. The three main categories are
continuously inflated (CI) structures, rigidized inflatable (RI)
structures, and single-inflation (SI) devices. The gas used to inflate
all three types must be light, non-contaminating to the spacecraft
instruments, non-condensing under given pressure and temperatures,
non-reactive with structural elements and able to be delivered reliably
and controllably.

SI and RI devices are only inflated once. SI devices, such as landing
bags are then discarded. RI structures, such as communication antennas,
light sails or solar shields, are made of materials that can be folded
and packaged, but harden once inflated and exposed to sunlight.

CI structures, such as data collection antennas, rover tires or
habitats present a different set of problems. They must be continuously
inflated throughout the life of the mission, and they invariably leak.
In addition, some CI devices can be very large. A reflecting membrane
currently envisioned for the ARISE (Advanced Radio Interferometry
between Space and Earth) mission may be 25 meters (around 83 feet) in
diameter.

"Preliminary characterizations studies show that either a tanked-gas or
systems that generate inflation gas via chemical reaction are
indicated," Roe explained. "Our prime candidate is the catalytic
decomposition of hydrazine, which produces a mixture primarily of
hydrogen and nitrogen."

Roe is doing conceptual designs for projects that are about 10 years in
the future. He is focusing both on determining good ways to inflate
devices and eliminating things that don't work. For example, subliming
solid systems used in the Echo series of balloons have contamination
and control issues that must be addressed before they could be used
reliably.

Optimization is another key issue, Roe indicated. Once a viable process
is determined, it must be made more efficient. Inflation systems have
already been reduced in size by 50 percent, but Roe believes that
further efficiencies and size reductions are possible.

"For the near-term the primary development focus is on RI and CI
structures," said Roe. "Inflation technology can be incorporated into
deployable solar arrays for power, solar shields for spacecraft thermal
management and antennas for data collection and communication."

Roe is presenting his findings in Atlanta on April 4, 2000, at the
American Institute of Aeronautics an Astronautics Joint Conference on
Structures, Structural Dynamics, and Materials.

==================
(7) ASTROBIOLOGY FIELD DRAWS RESEARCHERS

From Space.com, 5 April 2000
http://www.space.com/science/searchforlife/ames_astrobiology_000405_wg.html

By Martha Mendoza
Associated Press Writer

MOFFETT FIELD, Calif. (AP) -- Two years ago, NASA took a chance and
launched a new field of research christened "astrobiology" with a bold
Nobel laureate at the helm and about $10 million for research.

This week, at the first ever Astrobiology Science Conference, NASA
organizers were surprised when 600 scientists -- three times as many as
expected -- showed up brimming with research papers, new ideas and
enthusiasm about the questions of origins and evolution of life in the
universe.

"This is an irresistibly exciting field," said Baruch Blumberg,
director of the NASA Astrobiology Institute who won the 1976 Nobel
Prize for physiology and medicine. "It's like when Galileo first looked
through a telescope and everything he saw was new."

FULL STORY at
http://www.space.com/science/searchforlife/ames_astrobiology_000405_wg.html


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

(8) MARTIAN MAGNETIC FIELD AND ALH84001

From Everett Gibson <everett.k.gibson1@jsc.nasa.gov>

The martian magnetic field died during the first 500,000 to 700,000
years (Acuna et al., 1999 SCIENCE).  This was the same period when the
martian carbonates were formed (3.94 billion years ago, Borg et. al.,
1999, SCIENCE) in which the magnetites from the magnetotactic bacteria
were entrapped.

Everett Gibson

=================
(9) MARTIAN BACTERIAL MAGNETITE

From Oliver Morton <abq72@pop.dial.pipex.com>

Two points on Martian bacterial magnetite. One is that early Mars had  
one hell of a magnetic field, judging by the very strong magnetic bands
in the southern highlands seen by MGS, which are taken to be relics of
that era. Though the field is thought to have shut down early on (4bya
or so), the ALH84001 sample is itself from very early in Martian
history. Magnetotaxis could thus have been useful to bugs from the
ALH84001 era.

The other is that though bacterial magnetite is used in magnetotaxis,
it's not necessarily the case that that is all it has ever been used
for. In fact, that seems unlikely. Remembering that a biological
innovation needs to be beneficial at each stage of its evolution,
it's hard to see how magnetosomes would evolve from scratch as sensory
organelles, since there must be some size threshold below which a lump
of magnetite is not useful as a detector. It seems more likely that
bacteria found it useful to sequester away iron in magnetite for some
other reason, and then found a secondary sensory use for the magnetite
crystals they found themselves making. I seem to remember Joe
Kirschvink making arguments along these lines. So its quite feasible to
imagine the evolution of  biological magnetite with no magnetic field
to provide an environmental spur.

That said, Everett would probably have been better advised to have said
"magnetites highly similar to those seen in magnetotactic bacteria and
unlike any known non-biological forms".

Not that any of this means they are in fact bacterial.

best,

Oliver

=============
(10) METEORITE CONTAMINATION & A NULL HYPOTHESIS

From Michael Paine <mpaine@tpgi.com.au>

Dear Benny,

Abstracts for the 'First Astrobiology Conference', held this week at
NASA Ames Research Centre are online at
http://www.astrobiology.com/asc2000/program.html

The abstract of a paper by Andrew Steele et al. is below.

regards
Michael Paine

The Microbiological Contamination of Meteorites; A Null Hypothesis

A. Steele, University of Portsmouth, UK, NASA Johnson Space Center,
andrew.steele@easynet.co.uk; K. Thomas-Keprta, NASA Johnson Space
Center; F. W. Westall, NASA Johnson Space Center; R. Avci, Montana
State University; E. K. Gibson, NASA Johnson Space Center; C. Griffin,
University of Liverpool, UK; C. Whitby, University of Liverpool, UK; D.
S. McKay, NASA Johnson Space Center; J. K. W. Toporski, NASA Johnson
Space Center

During in the course of our investigations into the microbial
contamination of meteorites (including ALH84001, Nakhla, Murchison and
Allende) we have used 4 separate technique groups (Imaging, Surface
analysis, microbial culturing and direct DNA isolation) to detect the
presence of a wealth of heterotrophic microbial species. Undoubtedly 
the presence of these organisms in meteorites potentially has grave
implications for the organic and inorganic species within these
meteorites. Experiments with a contaminated chip of the Murchison
meteorite show that bacteria can mediate significant damage to the
surface of meteorites. Surface analysis shows that masses in the mid
400 AMU range in meteorites exactly resemble those found in terrestrial
biofilms and fossilised bacterial cells. By combining surface specific
Time of Flight secondary Ion Mass Spectrometry of fresh fracture
surfaces followed by (after analysis), SEM imaging of the same samples,
we have, in the case of ALH84001, been able to match certain high mass
peaks in the mid 500 AMU range with cellular features and the 441 peaks
with what appears to be a polymeric coating on the surface. We conducted
this analysis of a depth profile of ALH84001 and Nakhla and found both
to contain possible biomarkers and in the case of Nakhla living cells
all through the core of the meteorites. We have cultured several
organisms from Nakhla, ALH84001, Allende and Murchison and completed
16srDNA analysis of a number of bacterial and fungal species from
Allende, by direct isolation of DNA from the meteorite.
In the case of ALH84001 the techniques used to deny the McKay et al.,
(1996) hypothesis all failed to detect terrestrial micro-organisms
living within the meteorite. This is an obvious cause for concern in
the light of the Mars sample return mission. We contend that the reason
for this is that meteorites become contaminated on immediate contact
with the terrestrial biosphere at which time heterotrophic microbial
species begin to reprocess any organic material within the meteorite.
Subsequent analysis of the organic material would include microbial
products as well as intrinsic organic material. Our conclusions are
that a null hypothesis which states that ëall high molecular weight
organic material in these meteorites is terrestrial in originí, should
be applied to organic meteorite research. Undoubtedly this is not the
case but it hoped that through this approach and this hypothesis, we can
clarify the nature of any microbial action/contamination within
meteorites.

=============
(11) DOUBTS ABOUT VOLCANIC CATASTROPHE AD 536

From Steve Zoraster <szoraster@zycor.lgc.com>

Benny:

Although I enjoyed David Key's "Catastrophe: A Quest for the Origins of
the Modern World," I ended up doubting the volcanic eruption
explanation at the end of the book. Among the scientific "facts" I had
trouble with were:

1) The claim that "Up to ninety-six thousand cubic miles of gas, water
vapor, magma, and rock were hurled into the atmosphere." (Page 267 of
the American edition.) This sounds more like a Chicxulub scale event
than a larger Tambora.

2) The lack of reported tsunami impacts recorded in already literate
China, Japan, or India.  Krakatoa killed mainly through a tidal wave,
and it is hard to understand how an event so much larger, which
supposedly sundered Java from Sumatra, would not have caused a much
larger tsunami, with results recorded across vast distances in the
Pacific and Indian Oceans.

3) Fixing the date of the eruption at 535 when the calibrated C14 dates
are between 6600BC and 1300AD. (Note 1, Chapter 32. Page 316 of the
American edition.)

By the way, I would like to ask Mr. Key about these issues, but don't
know his e-mail. Can you or one of your readers help?

Steve Zoraster

=============
(12) SIXTH CENTURY "COMET" VECTOR

From Leroy Ellenberger < c.leroy@rocketmail.com >

Dear Joel,

I read your comments in 5 April CCNet and offer the following remarks:

1. I've read Saunders' review in New Scientist, but not Keys' book, and
cannot imagine how Keys could go so far down the "volcano road" in face
of the fact that there is no major volcanic acidity signal in the
Greenland ice cores at ca. A.D. 540 as there is a corresponding acidity
signal in Greenland for every other known major volcanic eruption in
the past 2000 years, while Baillie makes a good case in Exodus to
Arthur (1999), which was reviewed by New Scientist in their first issue
for 1999, for a cosmic vector associated with the climate crisis in the
sixth century.

2. The cosmic vector is NOT the close passage, or even an impact, of a
comet, per se, but the cumulative effects of successive atmospheric
accretion events over a number of years as Earth repeatedly intercepts
large amounts of cometary debris from the dense portion of a meteor
stream (in the case the Taurids, if Clube and Napier's model is on
point, as I believe it is), whose most spectacular manifestation would
be a succession of Tunguska-like detonations high in the atmosphere
which greatly attenuates surface-level insolation. Baillie makes the
case that much of the sixth century "dragon" lore associated with
Arthur and Beowulf was inspired by such events, at which time accounts
from China refer to dragons fighting at night and leaving the forests
trampeled as they passed, which is not too bad for a folk-impression of
a Tunguska-like event. Clube has documented the fact that every period
of millennial or eschatological concerns in the past 2000 years prior
to the 19th century, marked by portents in the sky, occurred at
times when Chinese records tell us the Taurid firefall flux was
enhanced. Cromwell rode the Taurid stream portents to fame and lost
favor when the payoff did not turn out as he predicted. But this aspect
of Cromwell's career is not dwelled upon recently nor evident in the
1960s film "Cromwell". I invite you to read my "Are Comets Evil?" at
the end of the file < http://abob.libs.uga.edu/bobk/velidelu.html > for
more of the flavor of Clube & Napier's model and how its impact on
culture has been largely overlooked, if not ignored.

Cheers,

Leroy Ellenberger

==============
(13) AND FINALLY: MEDIA BOO-BOO OF THE DAY

From Jeremy Tatum < UNIVERSE@uvvm.UVic.CA >

RE: Will a Killer Asteroid Hit the Earth?
http://www.time.com/time/reports/v21/science/asteroid.html

Wow! The Arizona Meteor Crater is 34-miles wide! Gosh, I must go down 
and see that sometime!

Jeremy Tatum

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