PLEASE NOTE:
*
CCNet 32/2001, 28 February 2001
-------------------------------
"It might sound like an ivory-tower question, but knowing
the makeup
of this asteroid -- both its internal structure and its chemical
composition-- has a practical application. The solar system is
littered
with space rocks more or less like Eros, and many come
uncomfortably close
to Earth. One day we may need to blow one apart (or deflect one
without
blowing it apart) to avoid an unpleasant collision. Near-Earth
asteroids are
also potential mining resources as humans expand into space. In
either
case, knowing more about them is a good idea!"
--NASA News, 27 February 2001
"We think there is too much negative energy floating around
our big
blue space-ship, in the light of a very positive U.K.
position-paper, on the most important technical challenge in
history. It
supports, in a big way, organizing an international team-effort
and that is
clearly where we should go."
--Andy Smith, 27 February 2001
"Discovering NEOs is a matter of some practical importance,
but of
little scientific interest. They're known to be there, their
numbers
are known to well within an order of magnitude. Characterising
their
surface properties is more interesting - but still only to a
relatively
small number. So it's quite reasonable for astronomers as a whole
not to be
particularly interested in the issue from a professional point of
view. It's
not that they are incapable of campaigning -- look at the work
they do on
light pollution, something which directly impacts their lives.
Its just
that most, I suspect, see NEO protection as no more
"their" campaign than
the campaign against nuclear proliferation is "their"
campaign. And
there's good reason for scientists not lending their weight as
scientists,
as opposed to as citizens, to campaigns outside their
field."
--Oliver Morton, 27 February 2001
(1) GAMMA-RAYS FROM AN ASTEROID
Ron Baalke <baalke@jpl.nasa.gov>
(2) NEW ANALYSIS OF METEORITE SHOWS KEY INGREDIENTS FOR LIFE ON
EARTH MAY
HAVE BEEN DELIVERED BY COMETS
Andrew Yee <ayee@nova.astro.utoronto.ca>
(3) MORE EVIDENCE OF LIFE ON MARS ROCK? NOT SO FAST
Space.com, 27 February 2001
(4) STRESS & CHAOS FORM TALLEST MOUNTAINS IN THE SOLAR SYSTEM
Andrew Yee <ayee@nova.astro.utoronto.ca>
(5) ASTEROIDEN: DIE GEFAHR AUS DEM ALL [ASTEROIDS: DANGER FROM
SPACE]
SPIEGEL Online, 27 February 2001
(6) WONDERFUL PROGRESS
Andy Smith <astrosafe@yahoo.com>
(7) WHY MANY ASTRONOMERS ARE NOT BOTHERED ABOUT NEO
PROTECTION
Oliver Morton <abq72@pop.dial.pipex.com>
(8) LIABILITY OF ASTEROID OWNERS FOR IMPACT DAMAGE
Michael Gerrard <Michael_Gerrard@aporter.com>
(9) NAKED-EYE COMET MAY NOT BE VISIBLE WITH NAKED EYE
Jonathan Shanklin <jdsh@bas.ac.uk>
(10) U.S. PLAN TO BUILD LARGE TELESCOPE
Daniel Fischer <dfischer@astro.uni-bonn.de>
(11) MORE ON LAVA ERUPTIONS AND IMPACTS
Michael Paine <mpaine@tpgi.com.au>
(12) BUCKY-BALLS
Bob Kobres <bkobres@uga.edu>
(13) TIME TO MAP NEAR MARS OBJECTS?
Jens Kieffer-Olsen <dstdba@post4.tele.dk>
(14) EARLY TERRESTRIAL LIFE - WHERE SCIENCE ENDS AND PHILOSOPHY
BEGINS:
COMMENTS ON MAX WALLIS' AND PAUL DAVIES' VIEWS.
Andrew Glikson <geospectral@spirit.com.au>
(15) UNUSUAL SEISMIC EFFECTS
Rolf Sinclair <rolf@santafe.edu >
===========
(1) GAMMA-RAYS FROM AN ASTEROID
From Ron Baalke <baalke@jpl.nasa.gov>
http://science.nasa.gov/headlines/y2001/ast27feb_2.htm
Gamma-Rays from an Asteroid
NASA Science News
Perched on the surface of asteroid 433 Eros, NASA's NEAR
spacecraft is
beaming back measurements of gamma-rays leaking from the space
rock's dusty
soil.
February 27, 2001 -- When NASA's Near Earth Asteroid Rendezvous
(NEAR)
spacecraft left for asteroid 433 Eros five years ago, scientists
weren't
certain what they would find when the probe arrived. Was Eros a
30-km
fragment from a planet that broke apart billions of years ago? Or
perhaps a
jumble of space boulders barely held together by gravity? Was
Eros young or
old, tough or fragile ... no one knew for sure.
But now, after a year in orbit and a daring landing on the
asteroid itself,
NEAR Shoemaker is beaming back data that could confirm what many
scientists
have lately come to believe: Asteroid Eros is not a piece of some
long-dead
planet or a loose collection of space debris. Instead, it's a
relic from the
dawn of our solar system, one of the original building blocks of
planets
that astronomers call "planetesimals."
As NEAR Shoemaker was heading for its historic landing on Feb.
12, 2001,
team members hoped the spacecraft --which was designed to orbit,
not land --
would simply survive. When it did survive, they set their sights
a little
higher. From its perch on the surface of the asteroid, NEAR's
gamma-ray
spectrometer (GRS) can detect key chemical signatures of a
planetesimal --
data that scientists are anxious to retrieve.
"The gamma-ray instrument is more sensitive on the ground
than it was in
orbit," says Goddard's Jack Trombka, team leader for the
GRS. "And the
longer we can accumulate data the better." NASA recently
gave the go-ahead
for NEAR's mission to continue through Feb. 28th, tacking four
days onto an
extension granted just after the spacecraft landed.
To do its work the GRS relies partly on cosmic rays, high-energy
particles
accelerated by distant supernova explosions. When cosmic rays hit
Eros, they
make the asteroid glow, although it's not a glow you can see with
your eyes;
the asteroid shines with gamma-rays.
"Cosmic rays shatter atomic nuclei in the asteroid's
soil," explains
Trombka. Neutrons that fly away from the cosmic ray impact sites
hit other
atoms in turn. "These secondary neutrons can excite atomic
nuclei (by
inelastic scattering) without breaking them apart." Such
excited atoms emit
gamma-rays that the GRS can decipher to reveal which elements are
present.
"We can detect cosmic-ray excited oxygen, iron and silicon,
along with the
naturally radioactive elements potassium, thorium and
uranium," says
Trombka. Measuring the abundances of these substances is an
important test
of the planetesimal hypothesis.
Planetesimals came to be when the solar system was just a
swirling
interstellar cloud, slowly collapsing to form the Sun and
planets. Dust
grains condensed within that primeval gas. The grains were small,
but by
hitting and sticking together they formed pebble-sized objects
that fell
into the plane of the rotating nebula. The pebbles accumulated
into
boulders, which in turn became larger bodies, 1 to 100 km wide.
These were
planetesimals -- the fundamental building blocks of the planets.
For reasons unknown Eros was never captured by a growing
protoplanet. It
remained a planetesimal even as other worlds in the solar system
grew and
matured.
Fully-developed planets like Earth are chemically segregated --
that is,
they have heavier elements near their cores and lighter ones at
the surface.
Planetary scientists call this "differentiation." If
Eros were a chip from a
planet that broke apart, perhaps in the asteroid belt, it would
exhibit
chemical signatures corresponding to some layer from a
differentiated world.
For example, Eros might be iron-rich if it came from the core of
such a
planet or silicon-rich if it came from the crust.
Instead, "orbital data from the x-ray spectrometer (a
low-energy cousin of
the GRS) showed Eros is very much like a type of undifferentiated
meteorite
we find on Earth called ordinary chondrites," says Andrew
Cheng, the NEAR
project scientist at Johns Hopkins University Applied Physics
Laboratory
(APL), which manages the mission for NASA.
Eros seems to harbor a mixture of elements that you would only
find in a
solar system body unaltered by melting (an unavoidable step in
the process
of forming rocky planets). But, says Cheng, there is a possible
discrepancy.
"The abundance of the element sulfur on Eros is less than we
would expect
from an ordinary chondrite. However, the x-ray spectra tell us
only about
the uppermost hundred microns of the surface, and we do not know
if the
sulfur depletion occurs only in a thin surface layer or
throughout the bulk
of the asteroid."
The GRS can go deeper, as much as 10 cm below the surface.
Although the
instrument can't detect sulfur, it is sensitive to gamma-ray
emissions from
other elements such as radioactive potassium that are indicators
of melting.
Like sulfur, potassium is a volatile element -- it easily
evaporates when a
rock is heated. Finding plenty of potassium would strengthen the
conclusion
that Eros is an unmelted and primitive body.
On the other hand, a widespread dearth of "volatiles"
would hint that Eros
isn't so primitive after all.
It might sound like an ivory-tower question, but knowing the
makeup of this
asteroid -- both its internal structure and its chemical
composition-- has a
practical application. The solar system is littered with space
rocks more or
less like Eros, and many come uncomfortably close to Earth. One
day we may
need to blow one apart (or deflect one without blowing it apart)
to avoid an
unpleasant collision. Near-Earth asteroids are also potential
mining
resources as humans expand into space. In either case, knowing
more about
them is a good idea!
"Our first four data sets are here and they look
great," says Jack Trombka.
"John Goldsten, the lead engineer for the gamma-ray
spectrometer at the
Johns Hopkins Applied Physics Laboratory, has done a fabulous job
making the
instrument work on the surface, which is a different environment
than orbit.
"We're just hoping to get as much data as we can before the
mission ends."
NEAR Shoemaker launched on Feb. 17, 1996 - the first in NASA's
Discovery
Program of low-cost, scientifically focused planetary missions --
and became
the first spacecraft to orbit an asteroid on Feb. 14, 2000. The
car-sized
spacecraft gathered 10 times more data during its orbit than
originally
planned, and completed all the mission's science goals before its
controlled
descent on February 12, 2001. Funding for the mission extension
comes from
the NEAR project.
==============
(2) NEW ANALYSIS OF METEORITE SHOWS KEY INGREDIENTS FOR LIFE ON
EARTH MAY
HAVE BEEN DELIVERED BY COMETS
From Andrew Yee <ayee@nova.astro.utoronto.ca>
University Communications Office
Scripps Institution of Oceanography
University of California-San Diego
Scripps Contacts:
Mario Aguilera or Cindy Clark, scrippsnews@ucsd.edu,
(858) 534-3624
For Release: February 27, 2001
NEW ANALYSIS OF METEORITE SHOWS KEY INGREDIENTS FOR LIFE ON EARTH
MAY HAVE
BEEN DELIVERED BY COMETS
An object that fell to Earth more than 136 years ago has revealed
new clues
about the origin of meteorites in space and new information about
how life
may have started on early Earth. The new study by researchers at
Scripps
Institution of Oceanography at the University of California, San
Diego, and
their colleagues shows that the Orgueil meteorite, which fell in
France in
1864, may be the first meteorite traced to a comet, rather than
from an
asteroid, the source widely believed to produce meteorites.
The contents within Orgueil, the study says, may have been just
the type of
fundamental ingredients necessary to help generate life on Earth.
Scientists
have generally believed that a wide variety of amino acids were
required for
the origin of life on Earth.
"Recent research suggests, however, that only a few types of
simple amino
acids may have been required, and that is exactly what we have
found to be
present in Orgueil," said Jeffrey Bada, a professor of
marine chemistry at
Scripps.
The study appears in the Feb. 27 issue of the Proceedings of the
National
Academy of Sciences and is authored by Bada, Daniel Glavin, and
Oliver Botta
of Scripps; Pascale Ehrenfreund of the Leiden Observatory in the
Netherlands; and George Cooper of the NASA Ames Research Center.
Although the Orgueil meteorite, named after the French town near
where it
fell in 1864, had been analyzed decades ago, Bada and his
colleagues
conducted a new study using sophisticated techniques and
instruments aimed
at detecting trace levels of amino acids. Amino acids are the
fundamental
components of proteins and are synthesized in living cells.
After obtaining a pristine piece of the interior portion of
Orgueil, the
researchers found that it contained a relatively simple mixture
of amino
acids, consisting primarily of glycine and beta-alanine. They
also analyzed
the sample's carbon isotope concentration and found that the
amino acids
were not derived from earthly contamination.
"We found that the amino acids in Orgueil are abiotic. They
were formed
without the help of biology, only chemical reactions," said
co-author Botta.
"We think these amino acids were synthesized in space."
The research team then compared their results with three other
meteorites:
Murchison and Murray, which have been studied extensively, and
Ivuna, a
meteorite that fell in Tanzania, Africa, in 1938 that had not
been analyzed
for amino acids.
The research team broke the meteorites down into two classes. The
Murchison
and Murray meteorites were placed in a category containing a
complex mix of
amino acids made up of more than 70 different types of amino
acids. Orgueil
and Ivuna, however, were categorized with a much simpler
composition made up
primarily of just two amino acids.
Based on the unique amino acid composition within Orgueil, the
researchers
were able to deduce information about the meteorite's past.
Murchison and
Murray are widely believed to be pieces of an asteroid, as are
virtually all
meteorites scientists have studied. However the paper suggests
Orgueil and
Ivuna show evidence that they are likely derived from a comet.
The amino
acid signatures within Orgueil and Ivuna suggest that these
compounds were
likely synthesized from
components such as hydrogen cyanide, which have been recently
observed in
the comets Hale-Bopp and Hyakutake.
"This suggested to us that what we may be seeing in Orgueil
and Ivuna are
the products of reactions that once took place in the nucleus of
a comet,"
said Bada.
"If it's true, this would be the first time that a meteorite
from the
nucleus of a comet has been identified," said co-author
Glavin. "There is
really a lot we don't understand about the chemistry of a comet
nucleus and
this would be our first insight."
Thus, the paper suggests, the amino acids that helped generate
life on Earth
may have been delivered by meteorites that were derived from the
remnants of
comets.
The study was funded by the National Aeronautics and Space
Administration
Specialized Center of Research and Training in Exobiology at
Scripps, the
Austrian Academy of Sciences, and the Netherlands Research School
for
Astronomy.
Scripps Institution of Oceanography, at the University of
California, San
Diego, is one of the oldest, largest, and most important centers
for global
science research and graduate training in the world. The National
Research
Council has ranked Scripps first in faculty quality among
oceanography
programs nationwide. The scientific scope of the institution has
grown since
its founding in 1903 to include biological, physical, chemical,
geological,
geophysical, and atmospheric studies of the earth as a system.
More than 300
research programs are under way today in a wide range of
scientific areas.
The institution has a staff of about 1,300, and annual
expenditures of
approximately $100 million, from federal, state, and private
sources.
Scripps operates the largest U.S. academic fleet with four
oceanographic
research ships and one research platform for worldwide
exploration.
Scripps Institution of Oceanography on the World Wide Web:
scripps.ucsd.edu
Scripps News on the World Wide Web: scrippsnews.ucsd.edu
Note: Image available upon request [or available at
http://www.sio.ucsd.edu/scripps_news/releases2001/bada_comet.html]
=========
(3) MORE EVIDENCE OF LIFE ON MARS ROCK? NOT SO FAST
From Space.com, 27 February 2001
http://www.space.com/scienceastronomy/solarsystem/meteorite_analysis_010227.html
By Robert Roy Britt
Senior Science Writer
After being batted around the solar system like some cosmic
softball, a rock
from Mars ended up on Earth thousands of years ago. Now, 17 years
after its
discovery, it has become science's most studied stone.
Researchers say the rock, known as the Allen Hills meteorite,
provides
compelling evidence that there was life on Mars, at least in the
distant
past. Few questions loom larger in space science today. If Mars
once had
life, than we humans would be faced with the increased likelihood
that life
has sprung up elsewhere, and we that are not alone.
The Latest Evidence for Life
On Monday, scientists announced that further study of "the
Mars meteorite,"
or Allen Hills meteorite, showed more evidence that small
structures in the
rock are in fact of biological origin. Click here to read the
full story.
But after five years of intense scrutiny, the scientific
community is no
closer to agreement on whether the rock tells us anything.
The meteorite, scientifically known as ALH 84001, reentered the
spotlight
yesterday, when researchers said they had developed further
evidence of
structures left in the rock by ancient Martian bacteria.
The evidence revolves around tiny structures called magnetite
crystals, so
small that millions of them could hide within the period at the
end of this
sentence. Researchers suspect these crystals were left behind by
bacteria
that aligned themselves to the magnetic field on the Red Planet.
While
scientists say they have ruled out the possibility that the
structures might
have been created by earthly organisms, a debate continues over
the nature
of the magnetite crystals.
A weak argument
The scientists studying the Mars rock "haven't really
eliminated the
possibility that these structures are inorganic in origin,"
said Jack
Farmer, director of the astrobiology program at Arizona State
University.
"Their argument has been weak from the beginning."
Ralph Harvey, a geologist at Case Western Reserve University, was
part of
the original team that found the rock from Mars stuck in the ice
in
Antarctica in 1984. Harvey said he welcomes the new findings, but
he thinks
the researchers are going too far with their interpretations.
"I certainly do not consider these findings 'proof' of
ancient Martian life
in ALH 84001," Harvey told SPACE.com.
Harvey called the work interesting, and added that the
researchers have done
a good job. But he said neither of the new studies did any tests
to explore
the alternative hypothesis that the magnetites might have been
created by
some inorganic process. Instead, Harvey said, they have merely
stated that
no inorganic process is known to produce similar structures.
"There is currently no known inorganic chemical means of
producing these
magnetite crystals with their unique morphologies," said
Dennis Bazylinski,
a geobiologist and microbiologist at Iowa State University who
coauthored
one of the papers.
"This is a very weak argument," Harvey said. "The
truth of the matter is,
nobody has really looked."
Harvey said a scientific theory can only achieve full strength
after
alternative ideas have been ruled out. And he says the meteorite
has had a
complex history of more than 4 billion years, "including
volcanism, impacts,
travel through space, evaporative processes, re-heating,
mechanical
disruption, time in the Antarctic ice. We should expect to see a
lot of
confusing and mysterious things."
Defense: An extensive search
Kathie Thomas-Keprta, lead author of one of the new papers,
responded that
the researchers have taken a more in-depth look at the structure
of the
magnetites and have done an "extensive" literature
search for other studies
that might show analogous structures created by inorganic means.
"We came up with zero," Thomas-Kperta said in a
telephone interview.
Thomas-Kperta said the detail of the team's original paper,
published in the
December issue of Geochimica et Cosmochimica Acta, was voluminous
and may
not have been read widely or thoroughly by critics.
Meanwhile, the international list of researchers jumping on the
Allen Hills
meteorite bandwagon has grown large. Seventeen researchers were
involved in
three papers made public yesterday. Much of the research into the
rock has
been funded by the National Science Foundation, the Smithsonian
Institution
and NASA's Astrobiology Institute.
NASA geologist David McKay, who was involved in the original
study of the
Allen Hills meteorite and coauthored the recent paper with
Thomas-Kperta,
staunchly defended the work against criticism. But he allows that
final
proof for life on Mars is not yet in.
"These shapes and features and properties that we found in
the Allen Hills
magnetite have been understood for years to indicate biogenic
origin," McKay
said today. "That doesn't mean they couldn't be produced by
non-biological
processes."
But McKay argues that no one has succeeded in producing similar
structures
via inorganic means, despite serious efforts (one such project is
going on
at the Johnson Space Center, where McKay and Thomas-Kperta work).
"At some point you have to...accept that the only way they
could be produced
is by biology," McKay said.
Research will continue. McKay expects proof of life on Mars to
come within
five years, based on study of a dozen or so Mars rocks found on
Earth.
"We're not expecting any one paper or any one line of
evidence to convince
people," McKay said. "But we think that over a period
of time...people will
be convinced by the evidence, not by us, not by claims in the
press."
More rocks, more clues
Meanwhile, more rocks from Mars have been studied by the same
researchers
who originally examined the Allen Hills meteorite.
Two meteorites, called Nakhla and Shergotty, showed the same
evidence of
microfossils and other remnants of early life as Allen Hills,
according to a
team of researchers led by Everett Gibson, a geochemist at JSC.
Gibson is the senior author on a paper discussing Nakhla and
Shergotty in
the Feb. 17 issue of journal Precambrian Research.
Studying our own backyard
Many scientists say we won't have proof of life on Mars until we
go there,
either with robots or humans, and study some rocks that have a
less random
history.
But Farmer, of the ASU astrobiology program, says an ultimate
answer may
first require a better understanding of life on Earth. He points
out that
though we know terrestrial life goes back several billion years,
it becomes
increasingly difficult to detect its signs the further back one
looks.
The Allen Hills meteorite -- a highly random sample from Mars
that has an
unknown origin -- has "underlined some of the big problems
that we face in
establishing biogenicity in old rocks," Farmer said,"
even on our own
planet."
Unless a sample of material is extremely well preserved,
searching for signs
of organic life within it is very difficult, he said. The trick
on Earth has
always been to find the few rare environments where the
signatures of life
have been preserved.
Missions to Mars, which could bring back samples for study here
on Earth,
need to be targeted to the places most likely to harbor
signatures of life,
Farmer said.
Copyright 2001, Space.com
============
(4) STRESS & CHAOS FORM TALLEST MOUNTAINS IN THE SOLAR SYSTEM
From Andrew Yee <ayee@nova.astro.utoronto.ca>
Washington University in St. Louis
Contact:
Tony Fitzpatrick, (314) 935-5257
Feb. 26, 2001
Stress, chaos form tallest mountains in the solar system
St. Louis, Mo. -- It takes a lot of stress, and a little chaos,
to create
some of the tallest mountains in our solar system. That is the
theory
proposed by earth and planetary scientists at Washington
University in St.
Louis studying mountain formation and volcanic activity on Io,
one of
Jupiter's many moons. The researchers analyzed images taken by
the Galileo
and Voyager spacecraft and found that Io's enigmatic mountains
may be the
combined result of heating, melting, and tilting of giant blocks
of crust.
The origin of Io's prodigious mountains has intrigued planetary
scientists
for over 20 years. Io, about the size of Earth's moon, is the
most
geologically active body in the solar system, with mountains up
to 55,000
feet tall (the summit of Mt. Everest is a meager 29,000 feet).
Io's surface
is dotted with active volcanoes spewing plumes of sulfurous gas
and emitting
vast streams of scorching lava. The heat released from Io -- from
lavas as
hot as 1,800 Kelvin or 2,800 degrees Fahrenheit -- is about 25 to
30 times
greater per square foot than the heat released from Earth. This
makes Io's
mountains, which are not themselves volcanoes, all the more
interesting,
because at these temperatures planetary scientists would expect
the surface
to be liquid or soft, with little topography to speak of.
How, then, can mountains form in such a furnace-like environment?
William B.
McKinnon, Ph.D, professor of earth and planetary sciences and
Andrew J.
Dombard, Ph.D., recent Ph.D at Washington University in St.
Louis, and Paul
M. Schenk, Ph.D., of Houston's Lunar and Planetary Institute,
answer this
geological conundrum in the February issue of the journal
Geology. The paper
is: "Chaos on Io: A model for formation of mountain blocks
by crustal
heating, melting, and tilting". The work was funded by
NASA's Planetary
Geology and Geophysics and Jovian Systems Data Analysis Programs.
"Two things work in concert to produce Io's
mountains,"says McKinnon "These
are compressive stress, due to the general movement or sinking of
the crust
closer to Io's center, and thermal stress which is generated when
regions of
cool crust suddenly become heated."
The combination of compressive and thermal stresses breaks up the
crust and
produces irregular, or chaotic, distributions of mountain peaks.
Slight
changes in the rate of lava flow from Io's mantle and the heating
of cooler
crust below the surface create the mountain-forming faults.
"Heat is actually trying to come out from deep in the
interior of Io, but
the crust is subsiding, or sinking, as new layers of lava are
laid down, all
on the order of one to several centimeters a year," says
McKinnon. "For this
heat, it's like trying to run up a down escalator; you run in
place. But if
the escalator slows down, meaning the lava eruptions slow down,
then you
(the heat) can in fact run to the top."
The researchers used stereoimaging -- a method where
three-dimensional
objects are reproduced by combining two or more images of the
same subject
taken from slightly different angles -- to reconstruct the
physical
topography of much of Io's surface. Maps of all the mountains and
volcanoes
on Io's surface were also made.
"The stereo data and high-resolution pictures taken by the
ongoing Galileo
mission allowed us and others to confirm that Io's mountains were
indeed
tilted fault blocks and not volcanoes," says McKinnon.
"You can see
sequences of mountains in early, middle, and late stages of
collapse; first
tall and steep with landsliding, then intermediate, and then
basically
flat."
Working out the irregular and chaotic distribution of the
mountain peaks --
which is quite different from the linear or arcuate patterns
found on Earth
-- allowed the researchers to propose that Io's mountains are the
result of
natural disturbances in the surface crust.
Io's lava makes it to the surface and normally radiates its heat
into space
(Io has no atmosphere to speak of). Of course, volcanoes are
notoriously
unstable, so if volcanism falters in one region, the surrounding
crust
begins to heat. This causes the crust to expand, generating
compressive
thermal stress in the crust, which in turn forces the crust
apart, forming
faults and mountains. This helps explain why concentrations of
mountains are
seen on Io that are separated from concentrations of volcanoes.
The
researchers propose that similar events may have occurred on
Europa, another
satellite of Jupiter, and the early Earth.
"Even though the moons have different surfaces -- Europa is
ice; Io, rock --
they have common geological phenomena," says McKinnon.
"This combination of
thermal and compressive stresses could operate in other
situations where a
body gets a lot of heat. The early Earth was very hot,
and therefore could have been more like Io in terms of tectonics
and
volcanism than the Earth today."
==========
(5) ASTEROIDEN: DIE GEFAHR AUS DEM ALL [ASTEROIDS: DANGER FROM
SPACE]
From SPIEGEL Online, 27 February 2001
http://www.spiegel.de/sptv/themenabend/0,1518,119605,00.html
Documentary & debate on the impact hazard to be shown on
German and Swiss TV
Sendetermin: Freitag, 2. März, 22.05 - 0.05 Uhr, VOX
Ein britischer Asteroidenforscher prognostiziert eine
alarmierende Häufung
todbringender Einschläge von großen Himmelskörpern in den
nächsten 10.000
Jahren. Bis zu 20 Millionen Menschen könnten dabei sterben.
Was ist dran an Katastrophenszenarios über die geheimnisvollen
Himmelskörper, die in Horrorfilmen den Weltuntergang
verursachen? Ist die
Erde tatsächlich eine "kosmische Schießbude", wie es
ein Wissenschaftler der
Nasa formulierte? Oder ist alles nur übertriebene Panikmache?
Elf Monate lang umkreisten sich der Asteroid Eros und die
Raumsonde
Shoemaker. Dann beendete die US-Raumfahrtbehörde Nasa ihr
Unternehmen mit
einem Finale, das in der Geschichte der Raumfahrt ohne Vorbild
ist. Am 12.
Februar landete die unter dem Namen Near gestartete Sonde direkt
auf dem
verhältnismäßig kleinen Himmelskörper. Der gelungene
"kontrollierte Absturz"
begeisterte nicht nur die amerikanischen Forscher.
Man erhoffte sich detaillierte Kenntnisse über die
Zusammensetzung und das
Alter der Asteroiden. Mehr über diese Planetoiden zu wissen sei
wichtig,
sollte es jemals nötig werden, einen solchen Himmelskörper vom
gefährlichen
Anflug auf die Erde abzubringen, erklärt Andrew Cheng vom
Near-Projekt an
der Johns-Hopkins-Universität in Baltimore im US-Bundesstaat
Maryland.
Astronomen und Impaktforscher aus aller Welt beschäftigen sich
seit Jahren
verstärkt mit dieser Thematik. In Tagungen, Projekten und
Veröffentlichungen
werden Wahrscheinlichkeiten, Folgen und Abwehrmaßnahmen eines
drohenden
Asteroideneinschlags auf die Erde diskutiert. Selbst die Nasa hat
ein
eigenes Komitee für die Überwachung der "erdnahen
Objekte" eingerichtet. Ist
die so genannte "Gefahr aus dem All" also doch realer,
als etliche Menschen
glauben wollen?
Der Themenabend von SPIEGEL TV dokumentiert in
Hintergrundberichten und
Studiogesprächen die Ergebnisse und Kontroversen der
Asteroiden-Forschung.
See also: http://de.news.yahoo.com/010226/71/1doop.html
============================
* LETTERS TO THE MODERATOR *
============================
(6) WONDERFUL PROGRESS
From Andy Smith <astrosafe@yahoo.com>
Hello Benny and CCNet,
We think there is too much negative energy floating around our
big blue
space-ship, in the light of a very positive U.K. position-paper,
on the most
important technical challenge in history. It supports, in a big
way,
organizing an international team-effort and that is clearly where
we should
go.
We want to thank all of our British colleagues for the effort put
into the
excellent study which was given to the government.
Tremendous Progress.
NEAR is sitting on EROS. How is that for progress?
LINEAR has presented another year of three digit NEO discovery
and we have
reduced the Critical Discovery Time (CDT - the time needed to
find and start
to track each of the 100,000 or so really dangerous objects up
there) from
about 10,000 years, in 1990, to about 300 years, last year. And
now, thanks
to our National Research Council (in it's new Decade Report) we
have a
proposal, on the table, to build a Super Terrestrial Asteroid
Telescope
(STAT - our name for it) which could reduce the CDT to a single
decade. What
are we waiting for? Let's build it and let's make it an
international
facility - funded by both public and private organizations and
individuals.
We're talking about $180 Million (US) and that's petty-cash for
the more
than 500 billionaires, in the World, and for scores of
governments. We need
that STAT, as soon as possible (or STAT) and we need the orbiting
early-warning system....and it all starts with a well-founded
international
program.
More Good News
We have several excellent interception/deflection systems
available to us,
now. Zenit and Delta are two good examples. We also have proven
asteroid/comet spacecraft and launch/control teams and
facilities.
International Planetary Protection Treaty (IPPT)
Our Planetary Protection Alliance is starting to take shape and
one of our
activities involves drafting a proposal for an international
planetary
protection agency. We are staring to list the important elements
and we want
to include all of the ideas in the CCNet brain.
We see clear roles for the IAU, Spaceguard, Space Shield, CCNet
and all of
the organizatons and
individuals, from around the world, who are working toward
asteroid/comet
emergency prevention and preparedness. Please send us any ideas
you have. We
plan to propose this as the first ammendment to the Outer-Space
Treaty of
1967, in accordance with Article 15.
U.S. Experience
The U.S. Congress started to talk about the need for
asteroid/comet
emergency preparedness, in the early 1990's and NASA was soon
involved.
Meetings were held and it looked like we were not making
progress...but
great progress is being made and good programs are now moving
ahead in the
U.S., Russia, Japan and elsewhere.
Now the United Kingdom is starting the important debate and may
well
spearhead the formation of a sound and needed international
program...supported by many countries and agencies. It is time.
So be of
good cheer and please keep up the good-work.
Cheers
Andy Smith
=============
(7) WHY MANY ASTRONOMERS ARE NOT BOTHERED ABOUT NEO
PROTECTION
From Oliver Morton <abq72@pop.dial.pipex.com>
Jay Tate <fr77@dial.pipex.com>
wrote:
"The bottom line is that, with the noble few exceptions
known to us
all, I see an amazing lack of support from the astronomical
community for
a project that has, unlike most, a direct relevance and appeal to
the
general public who, after all, pay the wages. I wonder why? It
can't be
ignorance, I sincerely hope it isn't a case of "I want that
money for my
pet project", so what can it be? Without more support
from the likes of
PPARC and the BNSC, the Spaceguard project will end up dead in
the water,
killed by endless tittle- tattle. That would be a case of gross
negligence of the highest order."
FWIW I've wondered about this myself, and my conclusion is that
it's not
negligence, it's just the effect of academic discipline.
Discovering NEOs is
a matter of some practical importance, but of little scientific
interest.
They're known to be there, their numbers are known to well within
an order
of magnitude. Characterising their surface properties is more
interesting -
but still only to a relatively small number. So it's quite
reasonable for
astronomers as a whole not to be particularly interested in the
issue from a
professional point of view.
It's not that they are incapable of campaigning -- look at the
work they do
on light pollution, something which directly impacts their lives.
Its just
that most, I suspect, see NEO protection as no more
"their" campaign than
the campaign against nuclear proliferation is "their"
campaign. And there's
good reason for scientists not lending their weight as
scientists, as
opposed to as citizens, to campaigns outside their field. That's
especially
true when it means funding might be moved away from their own
work (not a
negligible issue) and when at the same time any lobbying could be
misconstrued as self-interested (eg a call for new telescopes).
It's worth
remembering that when a scientific community *does* become
associated with a
cause, its methods, independence and good faith will be
relentlessly
questioned and impuned: see Benny's climate change specials,
passim.
Oliver Morton
========
(8) LIABILITY OF ASTEROID OWNERS FOR IMPACT DAMAGE
From Michael Gerrard <Michael_Gerrard@aporter.com>
Graham Richard Pointer wrote:
Re: U.S. COMPANY CLAIMS IT OWNS EROS http://www.OrbDev.com
My office-mates and I were trying to work out the legal
implications
- if Eros crashed into the Earth, could those affected sue this
company for
the damage caused? Any lawyers out there?
Here is a response from one lawyer.
A mere claim of ownership probably does not have much effect on
liability
for a purely natural event. If I claim to own a particular
asteroid, and
for some reason a governmental body agrees, then if that asteroid
collides
with the Earth and causes damage, this declaration of ownership
alone
probably won't give me liability (though my legal fees in
defending myself
against the million or so people who would sue me might well
bankrupt me).
However, if any of my actions contributed to the crash, it would
be another
story entirely.
The 1972 Convention on International Liability for Damage Caused
by Space
Objects (an international agreement pursuant to the Outer Space
Treaty of
1967) states in Article II: "A launching State shall be
absolutely liable to
pay compensation for damage caused by its space object on the
surface of the
earth or to aircraft in flight." The term
"launching State" is defined as
the State that launches or procures the launching of a space
object (such as
a rocket ship), or a State "from whose territory or facility
a space object
is launched."
If the asteroid collided with the Earth because of human
intervention, that
intervention probably involved a launch somewhere along the way.
(This is
reminiscent of Carl Sagan's cosmic billiards scenario.) Thus the
collision
would be seen as "damage caused by [a] space object,"
because causation need
not always be direct. Therefore the launching State would
probably be
liable in the first instance. In turn the launching State
could (unless it
had waived its rights to do so) bring legal action against any
private
entities that actually took the actions that led to the
collision. Since
presumably the private entities' assets would quickly be
exhausted by the
damage from any collision, the launching State would be left with
the
remaining liability.
---
This communication may contain information that is legally
privileged,
confidential or exempt from disclosure. If you are not the
intended
recipient, please note that any dissemination, distribution, or
copying of
this communication is strictly prohibited. Anyone who
receives this
message in error should notify the sender immediately by
telephone or by
return e-mail and delete it from his or her computer.
----------------------------------------------------------------------
Michael
Gerrard
Michael_Gerrard@aporter.com
Arnold &
Porter
Telephone: (212) 715-1000
399 Park
Avenue
Fax: (212) 715-1399
New York, NY
10022-4690
http://www.arnoldporter.com
=========
(9) NAKED-EYE COMET MAY NOT BE VISIBLE WITH NAKED EYE
From Jonathan Shanklin <jdsh@bas.ac.uk>
Dear Benny,
The prediction of a naked eye comet for Christmas 2001 rests
entirely on the
same principle that comet Kohoutek was expected to be a brilliant
naked eye
object. Comet LINEAR 2000 WM1 was discovered a long way from the
Sun and has
not been observed for very long. Its absolute magnitude is
therefore highly
dependent on the form of the magnitude law that is used.
Assuming a
'standard' value of 10 leads to an expectation of a naked eye
comet. Using a
more conservative value of 7.5, which is actually more standard
for long
period comets such as Kohoutek and Hale-Bopp, leads to a
reasonably easy to
see binocular comet of around 6th magnitude. In reality it is far
too early
to make any accurate predictions of the likely brightness and the
best we
can
say is that it could be anything from naked eye to
binocular.
Another major problem with the prediction is that it fails to
look at where
the comet will be in the sky. From the UK it will be totally
impossible to
see it at Christmas as the comet will be too far south in the
sky. This
means that there is no (that is zero!) chance of it being a naked
eye comet
for Christmas as far as UK readers are concerned. If you do want
to see it
(whatever magnitude it is) then you will need to be somewhere
between about
30 north and 50 south latitude.
Jonathan Shanklin
British Astronomical Association, Comet Section
http://www.ast.cam.ac.uk/~jds
========
(10) U.S. PLAN TO BUILD LARGE TELESCOPE
From Daniel Fischer <dfischer@astro.uni-bonn.de>
Why so excited now? The LSST was a key proposal in the Decadal
Survey when
it was published last May, and its role in hunting NEOs was made
clear then
- see http://www.astro.uni-bonn.de/~dfischer/mirror/190.html
for my own
coverage back then. While it is not guaranteed that every project
proposed
in these Decadal reports will eventually become reality, in the
past there
have
been more hits than misses.
Regards, Daniel
MODERATOR'S NOTE: The LSST was indeed mentioned months ago in the
U.S.
astronomy decadal report - and on CCNet. Mind you, the telescope
is to
observe changes in distant galaxies and the solar system - NEOs
are only
thrown in as an eye-catching afterthought. It's certainly not
intended as
integral part of an international Spaceguard programme.
===========
(11) MORE ON LAVA ERUPTIONS AND IMPACTS
From Michael Paine <mpaine@tpgi.com.au>
Dear Benny,
I recently heard from Franco Pirajno, from the Geological Survey
of Western
Australia. He advised me to add to my "extinction
graph" the Antrim Plateau
basalts, which is a major igneous province (LIP), recently dated
at about
511 Ma. This is close to the Cambrian/Ordovician mass extinction
(~505 Ma).
So far no sign of a large crater of this age. I have therefore
extended the
graph to 600 Ma. Franco is working on a possible Neoproterozoic
LIP 1070Ma
but there is too little evidence of impacts or extinctions going
back that
far to include it on the graph at
this stage.
See the update at http://www4.tpg.com.au/users/tps-seti/crater.html
Also the March 2001 issue of Scientific American has an article
on lava
eruptions and impacts:
http://www.sciam.com/2001/0301issue/0301scicit3.html
regards
Michael Paine
-----------------------
Scientific American, March 2001
http://www.sciam.com/2001/0301issue/0301scicit3.html
Volcanic Accomplice
Deadly impacts may have exacerbated massive eruptions
RENO, NEV.--The Chicxulub Crater, sprawled across the Gulf of
Mexico and the
Yucatán Peninsula, is an approximately 180-kilometer-wide
remnant of the
impact of a 10-kilometer-wide meteorite. It has been called the
smoking gun
in the extinction of the dinosaurs between the Cretaceous
and Tertiary periods 65 million years ago.
Some geologists, though, are starting to believe the meteorite
didn't act
alone. Volcanic phenomena known as superplumes may have been
accomplices in
that and other mass extinctions. "The general idea is that
plumes are
strengthened by impacts," says Dallas Abbott, a researcher
at Columbia
University's Lamont-Doherty Earth Observatory. At the Geological
Society of
America meeting in Reno last November, she showed a correlation
between the
timing of purported superplumes and large impact events--and
their possible
association with mass extinctions.
A plume can be visualized as a rising glob of liquid in a slowly
warming
lava lamp: material hotter than the surrounding rock of the
earth's mantle
pushes toward the surface in a concentrated stream. The funnel
ends below
the earth's outer crust, where the plume material spreads and
ponds. If the
molten rock erupts through the earth's surface, it releases gas
and
particulates into the air and produces lava flows. A superplume
may be a
gathering of small plumes, the size of those under the Hawaiian
Island chain
and Iceland, or one very large plume.
Abbott and her co-worker Ann Isley of the State University of New
York at
Oswego have catalogued remnants of possible superplumes,
including the
Deccan Traps in India, the Columbia River flood basalts in the
Pacific
Northwest and the Siberian Traps. These basalt flows and other
associated
rocks have large amounts of magnesium, indicating their origin in
the depths
of the mantle.
The researchers have also logged the probability of large impacts
occurring
at the same time as plume events. There are about 36 craters more
than 10
kilometers wide that formed over the past 120 million years,
Abbott says:
"It's a small sample of the potential number." Using
the record of earth and
lunar impacts, she calculates that of the estimated 400 large
impactors in
the earth's history, 40 percent should have hit continental
crust. The rest
should have struck ocean crust, in which case their craters would
have been
subducted into the mantle. "Therefore, we've found only 19
percent of the
big ones," Abbott concludes. Of those, "there's one
definitely associated
with the Permo-Triassic," she says of the mass extinction
250 million years
ago. The timing of the other five main mass extinctions, impacts
and plume
events is close, but you could argue about them, Abbott admits.
One of those events is Chicxulub--and its relation to the Deccan
Traps. Mark
Boslough of Sandia National Laboratories modeled the so-called
seismic
focusing that would occur from an impact event on the earth's
innards.
A large energy release on one side of the earth would set off
seismic waves,
which would travel through the mantle and converge at the
opposite side, or
antipode, creating another energy peak. That energy would be
converted to
heat, raising temperatures in the mantle and increasing melting
of the rocky
material--thereby heightening the effects of any plume already
there and
further contributing to conditions that lead to extinctions.
Abbott is unsure of the exact mechanisms that would strengthen an
existing
plume, but one possibility is that increasing temperature
differentials
between the core and the mantle would cause fingerlings of hot
core rock to
enter the earth's crust. The subsequent increase in volcanism and
release of
climate-affecting gases would be more than expected for a
superplume or
impact event alone.
Thanks to plate tectonics, however, the Deccan Traps may not have
been
antipodal at the time of the Chicxulub impact. If they weren't,
Boslough
says, "you would have to propose a second impact,"
directly opposite the
Traps, "in the eastern Pacific, on seafloor that's been
subducted." Any
geological evidence would be gone.
"You have to figure out what is in the geological
record" to draw any firm
conclusions, Boslough says. From his models, an impact might
produce the
same kinds of surface manifestations attributed to superplumes:
flood
basalts, large changes in sea level, radically increased
mechanical erosion
that alters ocean water chemistry, and sediment deposits that
indicate a
global change has occurred.
But Abbott and Isley think there is hard evidence for
impact-enhanced
superplumes: certain types of rocks associated only with
superplumes, say,
or some kind of universal, physical characteristic in the earth
consistent
only with major plume events. For now, though, not enough
evidence exists to
indict superplumes as an extinction accomplice.
Naomi Lubick
c2001 Scientific American
============
(12) BUCKY-BALLS
From Bob Kobres <bkobres@uga.edu>
Though evidence that two major extinction events were set into
motion by
abrupt extraterrestrial input should add force to the argument
for planetary
protection, there is still apt to be the illusion of a general
security due
to infrequency of truly dangerous impacts. Perhaps
the most immediate boon
to come from the Becker team's outstanding work will be funding
to look for
more recent samples of what might come to be accepted as
definitive proof of
cosmic crashes--layered caches of Bucky-Balls containing exotic
elements.
See: http://abob.libs.uga.edu/bobk/ccc/cc092900.html#BB
Stratified.
bobk
Bob Kobres
bkobres@uga.edu
http://abob.libs.uga.edu/bobk
706-542-0583
Main Library
University of Georgia
Athens, GA 30602
==============
(13) TIME TO MAP NEAR MARS OBJECTS?
From Jens Kieffer-Olsen <dstdba@post4.tele.dk>
David Morrison <dmorrison@arc.nasa.gov>
wrote:
Large-aperture Synoptic Survey Telescope: Quotes from the NRC
Astronomy & Astrophysics Survey Committee (2001)
[snip] By surveying the visible sky every week to a much fainter
level than can be achieved with existing optical surveys, LSST
will
open a new frontier in addressing time-variable phenomena in
astronomy. This 6.5-m-class optical telescope will detect 90
percent of the
Near-Earth Objects larger than 300 meters within a decade, and
will
enable assessment of the potential hazard each poses to Earth. .
. (p
38-39)
The Near-Earth Objects (NEOs) are asteroids with orbits that
bring
them close to the Earth. The orbits of many NEOs actually cross
that
of the Earth, making NEOs an impact threat to our planet.
Extrapolations
from existing data suggest that about 1000 NEOs are larger than 1
km
in diameter, and that between 100,000 and 1 million are larger
than 100 m. .
. . it is estimated that the probability of an NEO larger than
300 m
will strike the Earth during this century is [only] about 1
percent.
Nonetheless, it behooves us to learn much more about these
objects. Over a
decade, the LSST will discover 90 percent of the NEOs larger than
300 m,
providing information about the origin of these objects in the
process. . .
(p 58-61)
Dear Benny Peiser,
As the inevitability of rising to the challenge of mapping all
dangerous
objects in space has now become obvious to NASA decision-makers
the time has
come to ask, when should we aim to map NMOs (Near Mars Objects ).
Not only is Mars hit much more often than is Earth, but I gather
that stones
much smaller that 40m or so in diameter - below which
threshold our
atmosphere acts as an umbrella - can still create
havoc on Mars. Some of
the violent dúst-storms hampering earlier landing attempts may
well have
been caused by small impactors.
It is generally believed that this century will see the first
manned
expeditions to the surface of Mars. It has been seriously
proposed that
these early expeditions should dig in on Mars for a year or so
before
returning. I submit that it is irresponsible to launch such
an expedition,
unless it has been established beyond reasonable doubt that no
asteroid
impact - large or small - is due on Mars over the period of human
presence.
A programme to map Near Mars Objects must be initiated at least
20 years
before a proposal to launch a manned expedition is taken!
Yours sincerely
Jens Kieffer-Olsen, M.Sc.(Elec.Eng.)
Slagelse, Denmark
=============
(14) EARLY TERRESTRIAL LIFE - WHERE SCIENCE ENDS AND PHILOSOPHY
BEGINS:
COMMENTS ON MAX WALLIS' AND PAUL DAVIES' VIEWS.
From Andrew Glikson <geospectral@spirit.com.au>
Dear Benny,
I respond to Max Wallis' critical note "Panspermia science
vs
Ockham/Drake/Davies philosophy" (CCNet, 11-01-01), which
criticises
suggestions made in my essay "Extraterrestrial vs
terrestrial biogenesis:
when the total is greater than the sum of the part" (CCNet,
1.12.00), and to
comments made by Paul Davies' in his contribution "On
science and philosophy
in astrobiology" (CCNet, 11-01-01).
Wallis refers to the Hoyle-Wickramasinghe notion of comet-borne
and/or space
dust-borne microbe populations or microbe spores as
"panspermia science".
The distinction between the scientific method, philosophy and
fiction is
essential in an age in which the boundaries between these fields
are
progressively blurred, not least when the far reaching
achievements of
science result in confusion between what is consistent with
scientific
knowledge and understanding and what is not (Carl Sagan, The
Demon-Haunted
World - Science as a Candle in the Dark, 1997, Headline Books).
Of course,
the advance of unconfirmed suggestions is an essential tool of
science - so
long as this is acknowledged and suitable tests are suggested.
The onus of
proof is on the proponents.
Max Wallis states "He (Andrew Glikson) accepted that
panspermia is a
"testable" idea, so satisfies Popper's criterion for a
scientific
hypothesis.". However, in itself, that a suggestion is
testable is not a
sufficient basis for its view as scientific. Wallis' is
likely to reject
the following analogy, but does the fact that UFO notions are
testable - for
example through the search for relics in alleged landings sites -
render
them scientific??? Clearly not - the reason being that,
although there is
no lack of UFO proponents, no documented hard evidence is at
hand. As a
direct corollary to the pre-biotic nature of amino acids,
panspermia
life-in-comets notions must be regarded as pre-scientific
until-and-unless
they are subjected reality tests, namely the FALSIFYABILITY
principle - the
heart of the scientific method.
Referring specifically to the microbes-in-comets idea, central
questions
include (1) all known terrestrial microbes require liquid water;
(2) severe
radiation damage in outer space and solar grazing of comets, with
consequent
genetic disintegration. The existence of terrestrial
bacteria beneath ice
sheets and in deep crustal fractures does not constitute evidence
to the
contrary since both types of environments contain liquid
water. In so far
as some form of life may exist in comets and/or interstellar
dust, it would
have to be based on different biological principles than
recognised to date.
Paul Davies is correct in emphasising the hidden assumptions,
even wishful
thinking, which underlie philosophical sentiments of the day.
Examples
abound - inherent in early pantheistic world-views are
projections of living
forms and spirits on the universe, as in astrology. Central
to
Judeo-Christian religions is the domination of nature by a divine
human-like
mind. Nowadays, anthropocentric sentiments are perpetuated
by suggestions
that humans can - godlike - redesign terrestrial genetics and
engineer the
solar system. Inherent is the question free will, namely
whether humans
have a choice or are biologically-driven as other species with
whom we share
the bulk of our genes. As a student of natural history, I tend
more toward a
sense of reverence for the intelligence which underlies four
billion years
of terrestrial evolution rather than toward an ego-driven
arrogance of
self-anointed demigods.
Nowadays notions of bio-transport can be traced to a
semi-conscious cargo
cult mentality - Von Daniken-type "Chariots of the
Gods" - as well as a wish
to escape from an overpopulated, polluted and ozone-depleted
planet to a new
frontier - greenfields in space.
We do not know whether life has been transported through
intergalactic space
or not, nor is the question central to the understanding of life,
as
compared to the questions of the origin of bio molecules and
their evolution
all the way to technological civilisation. Should the
philosophical notion
of panspermia ever mature into science, I suspect it will do
little more to
explain the origin of biological complexity than do historical
inter-continental seafaring voyages explain the origin of the
human brain!
Andrew Glikson
Australian National University
Canberra, ACT 0200
24-02-01
==========
(15) UNUSUAL SEISMIC EFFECTS
From Rolf Sinclair <rolf@santafe.edu
>
Hi Benny --
This shows one source of acoustic and seismic signals that could
be mistaken
for meteoritic impacts -- or a possible weather-warning network
that could
be used to sense impacts.
Rolf
From "Newsday" Feb. 27, 2001
http://www.newsday.com/coverage/current/discovery/tuesday/nd2376.htm
Feeling for Funnels
Scientists offer proof that tornado touchdowns have seismic
effects
by Robert Cooke
Staff Writer
IT WAS A CLASSIC scene in old westerns: an Indian with one ear to
the ground
listens intently for the thunder of distant hoofbeats.
Pursuing that same idea, researchers in Alabama and Michigan find
that
seismic instruments can "listen" for the sound of
tornadoes touching down.
Thus a network of seismometers might give timely warning as a
deadly twister
draws near.
"We've found that there is a signal in the ground that is
generally related
to the strength of the tornado," said engineer Frank Tatom.
And the
tornado's seismic signal becomes detectable when it is truly
dangerous, when
its whirling funnel hits the ground, he said.
The winds in a tornado's business end "are going 200 or 300
miles an hour
over a rough surface, so it should have tremendous pressure
variations" that
produce a seismic signal in the ground, he added. After
calculating how much
vibrational energy would be pumped into the ground by a tornado's
funnel,
"we decided it [the signal] should be there." Proving
the signal exists was
difficult, however, because no one had seriously studied the idea
before.
Years earlier, a professor at the University of Mississippi had
raised the
possibility of tornadoes' making seismic "noise" but
didn't produce a
scientific paper on the idea. The State Technological University
in
Houghton, Mich., published its researchers' findings in a recent
issue of
the journal Seismological Research Letters.
Tatom, employed by Engineering Analysis, Inc., in Huntsville,
Ala., his home
state, said he was naturally interested in tornadoes, because
these deadly
storms are so prevalent where he lives. He was also working on
vibration
problems for the National Aeronautics and Space Administration,
and so the
two subjects came together for him.
He bounced the vibration idea off several people who work in the
sciences,
Tatom said, "but they said I didn't have any proof. So I
started looking for
eyewitnesses, and I found some here in Huntsville." One
report came from an
auto mechanic who told of feeling something coming as the sky
darkened. He
ducked under a desk in the gas station, with two other people,
and later
woke up out in the middle of the highway. A tornado had smashed
the gas
station to smithereens.
"He said there had been no wind and no sound, but the sky
looked a little
bit funny" before the twister hit, Tatom said. "So I
asked him how he knew,
and he responded, 'I could feel the vibrations through my
feet.'" Further
research uncovered other people who had "felt"
tornadoes coming in Texas,
Oklahoma, Connecticut and Pennsylvania. "We got them all
over the country,"
Tatom said.
The problem was that all the evidence was anecdotal -people
feeling
things-rather than scientific observations. So the next step was
to look
into historic records to see where tornadoes had touched down
near seismic
recording stations.
"We drew 10-mile circles around each station and then
searched for tornadoes
within 10 miles," Tatom explained. "We checked the
times and then looked at
the [seismic] files for those times." They hit paydirt;
there were clear
records of seismic signals that coincided with tornadoes
thrashing across
the countryside. "But even that was argued as not being
proof" of the
connection, he recalled.
"So we built our Snail, a seismometer hooked up to a
computer, which could
be put out near tornadoes. We have six of them, and we
interviewed storm
chasers," who would be out pursuing violent storms anyway.
Within three storm seasons "we had three successful
hits," proving that big
tornadoes begin shaking the ground when their funnels touch down,
Tatom
said.
Success at last.
That achievement, he said, led to creation of instruments-called
Owl and
Mole-that have the potential to become parts of tornado warning
networks.
Tatom explained that Moles would be seismic stations buried at
strategic
locations.
When triggered by appropriate shaking, Moles would radio a
central station,
and these would send signals to Owls in people's homes. Like
smoke alarms,
the Owls would sound a signal loud enough to awaken people.
At present, the U.S. Weather Service's warning system -based on
the radar
system called Nexrad-can warn of storms coming, but it cannot
tell whether a
tornado has touched down. The result, Tatom said, is that four
out of five
warnings turn out to be false alarms.
Because of that, people don't always react swiftly to warnings.
In contrast, "our signal doesn't occur unless a tornado is
on the ground,"
and that would mean the danger is real and immediate." No
government agency
or private corporation has yet offered to finance such a system.
Two
government agencies-the National Oceanic and Atmospheric
Administration and
the Federal Emergency Management Agency-have expressed interest,
Tatom said.
Private funding is also being sought.
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