PLEASE NOTE:
*
CCNet 7/2002 - 10 January 2002
-----------------------------
"This week's alarming close encounter between Earth and a
hurtling
300-metre-wide rock has renewed calls for an insurance policy
against the world's worst conceivable eco-disaster - the
high-speed
impact of an asteroid or comet.... Australia now has a new
minister for
science. The relatively modest sum of $1 million a year would
give this
country a seat at the high table of the UN task force and
kick-start a
revivified observational program. Far greater sums are routinely
earmarked
for insuring this nation against other rare disasters such as
large
earthquakes."
--Paul Davies, Sydney Morning Herald, 10 January 2002
"The only solution to this risk is to set up powerful
telescopes to
study the path of meteors and asteroids, and use space technology
to
destroy or deflect NEOs before they strike Earth. Also, a
forewarning of
a 'hit' can help in shifting the people of that area to another
location
in order to avoid tragedy."
--Sir Crispin Tickell, The Indian Express, 10 January 2002
"Disappointed after failing to take advantage of Earth's
relatively
near miss with a large asteroid on Monday, scientists today
excitedly
unveiled what they called an "asteroid chute" that they
said will direct
the next massive space object directly into Earth's path, where
it can
be studied more closely...."
--SatireWire.com, 9 January 2002
(1) LOOKING OUT FOR THE MOTHER OF ALL COMETS
Sydney Morning Herald, 10 January 2002
(2) SPACE BULLETS HURLING THROUGH THE SKY TICKLE TOP BRITISH
SCIENTIST
The Indian Express, 10 January 2002
(3) ASTEROID'S CLOSE PASS NOT UNUSUAL, BUT DIRECT HIT WAS
UNLIKELY
San Francisco Chronicle, 9 January 2002
(4) LIFE HITCHING A RIDE TO EARTH
Andrew Yee <ayee@nova.astro.utoronto.ca>
(5) NEW BOOK: ACCRETION OF EXTRATERRESTRIAL MATTER THROUGHOUT
EARTH'S
HISTORY
Birger Schmitz <birger@gvc.gu.se>
(6) THE TERRIBLE LIZARD: THE FIRST DINOSAUR HUNTERS AND THE BIRTH
OF A NEW
SCIENCE
Deborah Cadbury
(7) DRAWING OUT LEVIATHAN: DINOSAURS AND THE SCIENCE WARS
Keith M. Parsons
(8) SENATE NATURAL HAZARD CAUCUS AND OTHER NEAR-MISSES
Andy Smith <astrosafe@yahoo.com>
(9) NUMERICAL MISQUOTES
David Morrison <dmorrison@arc.nasa.gov>
(10) TSUNAMI FROM A 300m ASTEROID
Nigel Holloway <nigel.holloway@ukaea.org.uk>
(11) QUADRANTIDS DEBATE
Marco Langbroek <m.langbroek@rulpre.leidenuniv.nl>
(12) WHAT MORE DO THEY WANT?
Jonathan Tate <fr77@dial.pipex.com>
(13) SUPERNOVA I
Oliver Morton <abq72@pop.dial.pipex.com>
(14) SUPERNOVA II
Jonathan R. Ellis <John.Ellis@cern.ch>
(15) SUPERNOVA III
Martin Barstow <mab@star.le.ac.uk>
(16) STONEHENGE: AN EARLY IMPACT WARNING DEVICE?
Worth Crouch <doagain@jps.net>
(17) AND FINALLY: SCIENTISTS TO STUDY GIANT ASTEROIDS - BY
STEERING THEM
INTO EARTH
Are Major Asteroid As Dangerous As
Predicted? The Answer Arrives in
2003
===================
(1) LOOKING OUT FOR THE MOTHER OF ALL COMETS
>From Sydney Morning Herald, 10 January 2002
http://www.smh.com.au/news/0201/10/opinion/opinion1.html
It's time for Australia to get back in the hunt for the asteroid
that could
wipe out life on Earth, writes Paul Davies.
This week's alarming close encounter between Earth and a hurtling
300-metre-wide rock has renewed calls for an insurance policy
against the
world's worst conceivable eco-disaster - the high-speed impact of
an
asteroid or comet. Astronomers have known for a long time that
cosmic
objects occasionally slam into our planet, causing huge
destruction. Most
likely this was the way the dinosaurs met their end 65 million
years ago. It
may be us next.
Direct hits by space rocks are undeniably rare events but are by
no means
unknown. In 1908, thousands of square kilometres of remote
Siberian forest
were flattened when an object the size of an office block
exploded over the
tundra with the power of a 15-megaton bomb. Because the event
occurred in a
region inhabited only by a handful of reindeer herdsmen, the
death toll was
mercifully low. Had it been over Europe, millions would have
perished.
Scientists reckon that explosions like this happen somewhere on
Earth once
or twice a century and are unpredictable. They are even more
worried,
however, about bigger bangs. If a 1km-wide asteroid struck at a
typical
speed of 30km per second, the effects would be awesome. The blow
would
excavate a crater 20km across, spewing huge quantities of dust
and rock into
the atmosphere.
Molten debris would rain down across the globe, igniting
conflagrations that
would make Sydney's recent bushfires seem tame by comparison. The
seismic
shock, blast wave and ensuing super-hurricane would flatten
buildings for
thousand of kilometres. Nuclear winter conditions would follow,
with the sun
blotted out for months, causing worldwide crop failures. Weeks of
acid rain
would complete the picture of ecological calamity.
If the object plunged into the sea, tsunamis hundreds of metres
high would
add to the mayhem by inundating coastal cities across the
hemisphere.
The movie Deep Impact graphically portrayed the aftermath of a
comet strike.
Though the science in the film left a lot to be desired, the
general message
was accurate enough. It's hard to estimate how many people would
eventually
die from such a disaster, but if you include disruption in world
trade,
economic collapse and social breakdown, the figure tops 1billion.
So how likely is a cosmic catastrophe of this horrendous
magnitude?
Astronomers believe about a thousand asteroids of a kilometre or
more in
size are crisscrossing Earth's orbit, each a potential killer. On
average,
our planet takes a hit from one of these large rocks every
100,000 years or
so. This makes it roughly a million-to-one chance that a billion
people will
die this month from a cosmic impact. In actuarial terms, that
translates
into an average expectation of death of about a thousand people a
month,
which leads to the oft-cited statistic that the chance of being
killed by an
asteroid is greater than the chance of dying in a plane crash.
However you cut the numbers, it's clear that Australians worry
far more
about much less dangerous hazards, such as the sudden release of
buried
nuclear waste or an outbreak of anthrax.
The good news is that we have the technology to track down the
most
dangerous of the killer asteroids within a couple of decades,
using a
network of telescopes. For years astronomers have catalogued the
orbits of
stray asteroids they have stumbled across while scanning the
skies for other
objects, but dedicated searches are relatively rare.
Australia once had a flourishing asteroid-detection program led
by Duncan
Steel at the Anglo-Australian Observatory. For a time Steel and
his
colleagues were second only to the United States in finding rogue
objects
threatening Earth. And crucially for determining asteroid orbits,
they were
uniquely based in the Southern Hemisphere. Sadly, the Howard
Government
pulled the funding plug and years of lobbying failed to get the
program
restored. In the meantime, Steel has moved to England.
There is no reason why Australia should shoulder the burden of
planetary
defence alone. The threat of cosmic impact is truly global and
each nation
should play a part.
Several years ago I was invited to debate the topic at the World
Economic
Forum in Davos, Switzerland. I told world leaders that in spite
of its past
track record in the field, Australia was no longer prepared to do
anything
about the impact threat.
Fortunately Britain's science minister, Lord Sainsbury, left that
discussion
in more positive mood. Last year, after a lively debate in the
House of
Lords, he committed the British Government to a £30 million ($82
million)
asteroid-hunting project [what?! Lord Sainsbury must have told
Paul
something which he failed to pass on to the British public -:),
BJP}. Since
then, the OECD and the United Nations have woken up to the threat
and
Britain has agreed to head a multinational task force.
Australia now has a new minister for science. The relatively
modest sum of
$1 million a year would give this country a seat at the high
table of the UN
task force and kick-start a revivified observational program. Far
greater
sums are routinely earmarked for insuring this nation against
other rare
disasters such as large earthquakes.
People often ask what use it would be to know when (and it is
when, not if)
the next big impact is destined to occur. What could we do about
it anyway?
Scientists remain divided about the feasibility of deflecting an
incoming
asteroid. Controlled nuclear explosions near the surface of a
threatening
object could nudge it into a near-miss orbit if it was spotted
soon enough.
At the moment, we would probably get just a few seconds warning
of a
civilisation-destroying impact. Ideally, some decades are needed
to plan and
execute a deflection mission. If an observational program
determined that
the next impact was 2000 years away, we could breathe a sigh of
relief and
leave it to future generations to worry about. But if D-Day
turned out to be
in, say, 2030, we'd need to put our thinking caps on. Nobody
would then
begrudge the cost of the search program.
Our planet is littered with the scars of past impacts. Australia
alone has
more than 20 identified craters. Lake Acraman on the Eyre
Peninsula is the
remnant of a 600-million-year-old collision that left a hole more
than 100km
across. Events of this magnitude would have wiped out the
majority of
Earth's species and reset the evolutionary clock.
Clearly impacts have played a key role in the history of life.
Hunting
killer asteroids and comets is not just a matter of human
survival. It also
casts important light on how life began on this planet, and the
way it
developed over billions of years. For a modest investment in
scientific
resources, Australia could once more play a part in this
important
endeavour.
Paul Davies is a physicist in the Australian Centre for
Astrobiology at
Macquarie University. His latest book is How to Build a Time
Machine
(Penguin).
Copyright 2002, SMH
SEE ALSO: BIG BANG THAT ENDS IT ALL
>From The Age, 10 January 2002
http://www.theage.com.au/news/state/2002/01/10/FFXYLKLZ7WC.html
=============
(2) SPACE BULLETS HURLING THROUGH THE SKY TICKLE TOP BRITISH
SCIENTIST
>From The Indian Express, 10 January 2002
http://cities.expressindia.com/fullstory.php?newsid=6353
Vijay Singh
Mumbai, January 8: 'THE sky is falling'! Say that aloud or in a
whisper, but
Sir Crispin Tickell will not be tickled pink. For he knows about
rocks, as
big as trees, trucks and trains, hurling through space at
monstrous speeds -
sometimes barely scraping past Earth, and occasionally slamming
head on.
Sir Tickell is part of a three-member Task Force set up by the
British
government in January 2000, to study the risks involved due to
Near Earth
Objects (NEOs) such as meteors and asteroids.
And this Chancellor of the University of Kent at Canterbury, is
currently in
the city as one of the visiting British scholars for the
'India-UK Science
Festival 2002'. Like any other environmentalist, Sir Tickell is
worried
about Mother Earth.
A member of the Bombay Natural History Society, he has written
books on
global warming, delved on population explosion, debated on
preservation of
hills and studied the early history of our planet. But what
really gets Sir
Tickell on his toes is ET - the extra-terrestrial.
''Extra-terrestrial objects or 'space bullets' like meteors and
asteroids,
have hit Earth in the past, and will do so in the future. Just a
few days
back most newspapers reported how a giant asteroid was too close
to Earth
for comfort - enough to wipe out an entire country,'' Sir Tickell
told
Newsline.
''Our Task Force has spent over six months travelling around the
globe to
study space and the dangers lurking up there. We also visited the
Pentagon
in the US, as they have also carried out a detailed study on the
subject.
You will be amazed to know that in the year 2000, a space rock of
barely 5
metre diameter exploded in the sky before hitting an icy
terrain,'' he
informed. A huge amount of sulphur was also released in the air
as a result
of the explosion.
In 1908, another huge 60-metre long space rock (the size of
former warship
INS Vikrant) had hit Siberia at the speed of 20 kilometres per
second. ''If
instead of Siberia it were Mumbai, I'm afraid this city would
have been
finished by the impact,'' remarked Sir Tickell, stressing on the
ever-present danger.
The Shoemaker-Levy comet that had rammed into Jupiter in 1994,
for example,
was travelling at a speed of 70 kilometres per second, and had
broken down
into several fragments on entering Jupiter's atmosphere - one of
these
fragments was a big as Earth! (sic)
''The only solution to this risk is to set up powerful telescopes
to study
the path of meteors and asteroids, and use space technology to
destroy or
deflect NEOs before they strike Earth. Also, a forewarning of a
'hit' can
help in shifting the people of that area to another location in
order to
avoid tragedy,'' he said.
Sir Tickell is one of those who believe that the theory of a
giant asteroid
responsible for dinosaurs' extinction holds water.
''A 180-kilometre long asteroid [10-km are big enough to do the
trick, BJP]
had crashed in Mexico over 65 million years ago, leading to a
'nuclear
winter' as the sun's rays could not penetrate down. This killed
hundreds of
species, and dinosaurs were probably one of them,'' said the
scholar.
So should people stop going out to the beaches and nature camps,
lest they
are hit by a
meteor?
"According to an American study, the risk of being killed in
a plane crash
is just one in 2,50,000. And the same risk applies to being hit
by an
extra-terrestrial object," he informed.
However, just this one-in-2,50,000 'space hit' could eliminate
half of
Earth's plant and animal species. Now who is really tickled by
this
probability?
© 2001: Indian Express Newspapers (Bombay) Ltd. All rights
reserved
==========
(3) ASTEROID'S CLOSE PASS NOT UNUSUAL, BUT DIRECT HIT WAS
UNLIKELY
>From San Francisco Chronicle, 9 January 2002
http://www.sfgate.com/cgi-bin/article.cgi?f=/chronicle/archive/2002/01/09/MN184722.DTL
Asteroid's close pass not unusual, but direct hit was unlikely
Large meteorites rock Earth every 100,000 years
David Perlman, Chronicle Science Editor
An asteroid big enough to turn the Bay Area into a giant crater
zipped
within 400,000 miles of Earth on Monday, but scientists said
yesterday that
it was never on course to crash -- so no need to worry, at least
not this
time.
The solid chunk of space rock, dubbed 2001 YB5 and nearly 1,000
feet across,
was spotted by telescopes on Maui and Palomar Mountain (San Diego
County)
just after Christmas. Astronomers immediately calculated its
precise orbit,
which will send it past Venus, Mars and Mercury on its journey
around the
sun.
"If it had been on course directly toward Earth and hit the
Peninsula, it
would have made a crater out of the Bay Area and probably take
out most of
California and Nevada too," said astronomer David Morrison,
director of
space research at NASA's Ames Research Center in Mountain View.
"But this one had precisely a zero chance of hitting the
Earth anywhere,"
said Steven Pravdo, project manager of NEAT, the space agency's
Near-Earth
Asteroid Tracking system based at the Jet Propulsion Laboratory
in Pasadena.
The likelihood of any asteroid that size ever (sic) actually
hitting the
Earth is extremely remote, astronomers agree. Although they
consider an
asteroid flying 400,000 miles from Earth as a really close pass,
this one
was actually a lot farther away than the moon, which is 238,000
miles away.
According to Pravdo, the NEAT system has spotted 322 asteroids at
least a
kilometer -- six-tenths of a mile -- in size out of the estimated
500 to
1,000 such objects now estimated to be flying in orbits that
bring them
anywhere near the Earth.
"There's a handful that represent at least a remote
possibility of actually
hitting the Earth in the next tens to hundreds of years,"
Pravdo said, "but
we can't be be sure because there's always some uncertainty to
any
calculation like that."
The NEAT system is actually designed to detect kilometer-size
asteroids,
Morrison said, and its goal is to detect and plot the orbits of
at least 90
percent of all near-Earth asteroids that size in the next five
years.
It was an unexpected break that the NEAT telescopes spotted the
relatively
small one last month. "At least two or three others that
size probably come
just as close every year," he said, "but we just don't
see them."
Morrison maintains an updated asteroid and comet site on the Web
at
www.impact.arc.nasa.gov/index.html.
The Internet site for the NEAT system is
www.neat.jpl.nasa.gov/.
Asteroids are rocky objects -- some partly metallic and many
containing
organic molecules -- that orbit the sun and are considered minor
planets by
astronomers. Most of them lie in a belt between the orbits of
Mars and
Jupiter, although some are orbiting as far out as Saturn.
They range in size from one with a diameter of about 650 miles,
named Ceres,
down to many thousands that are only the size of pebbles. They
have been
bombarding Earth and the moon since they were born.
Astronomers estimate that modest-size asteroids hit the Earth
every century
or so, while potentially (sic) dangerous ones larger than a
half-mile in
size may have hit only once every 100,000 years. Those are large
enough,
however, to be detected and tracked many years before they come
close, the
scientists say, although deflecting one would be a big problem --
requiring
monster rockets fired directly at it in order to change its
orbit.
Scientists consider it virtually certain that a really huge
asteroid more
than six miles across crashed into what is now the Yucatan
Peninsula some 65
million years ago and wiped out the dinosaurs as well as nearly
half of all
other forms of life.
©2002 San Francisco Chronicle
==============
(4) LIFE HITCHING A RIDE TO EARTH
>From Andrew Yee <ayee@nova.astro.utoronto.ca>
New Scientist
http://www.newscientist.com
UK CONTACT:
Claire Bowles, New Scientist Press Office, London
Tel: +44(0)20 7331 2751 or email claire.bowles@rbi.co.uk
EMBARGOED UNTIL WEDNESDAY 9 JANUARY 2002 19:00 GMT
Life hitching a ride to Earth: Bugs could travel to Earth in
comfort
aboard Martian meteorites
FOR the first time, millions of bacterial spores have been
purposely exposed
to outer space, to see how they are affected by solar radiation.
The results
support the idea that life could have arrived on Earth in the
form of
bacteria carried from Mars on meteorites.
The idea that life started elsewhere and spread through space is
called
panspermia. It was first proposed in 1903 by the Swedish chemist
Svante
Arrhenius, who suggested that solar radiation might propel single
spores
across solar systems. Then, in the 1970s, astronomers Fred Hoyle
and Chandra Wickramasinghe studied the infrared spectra of
interstellar
grains of dust and concluded that they were dried, frozen
bacteria. They put
forward the controversial suggestion that life on Earth
originated when such
bacteria arrived from space. But critics of their work said that
cosmic rays
and ultraviolet radiation from the Sun would kill unprotected
spores.
Recent discoveries of Martian meteorites that have reached Earth
have raised
the possibility that bacterial spores could have hitched a ride
on these
rocks (New Scientist, 15 January 2000, p 19). Most meteorites
spend millions
of years in space, but meteorites taking a direct route would
make it from
Mars to Earth in just a few years -- too short a time to
experience much
damage from deadly cosmic rays.
The Sun's UV radiation might still pose a danger, however. To
assess its
effects, Gerda Horneck of the German Aerospace Centre in Cologne
and her
colleagues carried out a series of remote-controlled two-week
experiments
aboard the Russian Foton satellite. They started by exposing
nearly 50
million unprotected spores of the bacterium Bacillus subtilis
outside the
satellite. This is the first time any living organism has been
purposely
released into space. "You are not allowed to do that if you
have a human
mission, but we could do it on a Russian satellite," says
Horneck.
UV radiation from the Sun killed nearly all the spores,
confirming that
single bacteria would not survive long enough in space to travel
from one
planet to another. The same happened when the spores were behind
a quartz
window, so the researchers did the rest of their experiments
with the spores confined under quartz.
To test whether meteorites might protect the bacteria on their
journey
through space, Horneck and her colleagues mixed samples of 50
million spores
with particles of clay, red sandstone, Martian meteorite or
simulated
Martian soil, to make small lumps a centimetre across. In most of
the
samples, between 10,000 and 100,000 spores of the original 50
million
survived. And when mixed with red sandstone, nearly all survived.
The
results suggest that even meteorites as small as a
centimetre in diameter could carry life from one planet to
another, if they
completed the journey within a few years.
"Early in the history of Mars and Earth, there could have
been an exchange
of biological material between the two planets," agrees
Benton Clark, a Mars
exploration specialist at Lockheed Martin in Colorado.
Author: Anil Ananthaswamy
More at: Origins of Life and Evolution of the Biosphere (vol 31,
p 527)
New Scientist issue 12 January 2002
PLEASE MENTION NEW SCIENTIST AS THE SOURCE OF THIS STORY AND, IF
PUBLISHING ONLINE, PLEASE CARRY A HYPERLINK TO:
http://www.newscientist.com
===============
(5) NEW BOOK: ACCRETION OF EXTRATERRESTRIAL MATTER THROUGHOUT
EARTH'S
HISTORY
>From Birger Schmitz <birger@gvc.gu.se>
NEW BOOK: ACCRETION OF EXTRATERRESTRIAL MATTER THROUGHOUT EARTH'S
HISTORY
Edited by B. Peucker-Ehrenbrink and B. Schmitz,
Kluwer Academic/Plenum Publishers, 2001, xxvi + 466 p. (more info
on
www.wkap.com)
Contents:
Foreword, Walter Alvarez
Preface, Bernhard Peucker-Ehrenbrink and Birger Schmitz
I. The Origin and Properties of
Dust Impacting the Earth,
Donald E. Brownlee
II. Sources and Orbital Evolution of
Interplanetary Dust Accreted by Earth,
Stephen J. Kortenkamp,
Stanley F. Dermott, Debra Fogle and Keith Grogan
III. Delivery of Material From the Asteroid
Belt,
Paolo Farinella, David
Vokrouhlicky and Alessandro Morbidelli
IV. The Influx of Comets and their
Debris,
William M. Napier
V. Spacecraft Measurements of the
Cosmic Dust Flux,
Herbert A. Zook
VI. Magnetospheric Effects on the Cosmic
Dust Input into the Earth's Atmosphere,
Antal Juhasz and
Mihaly Horanyi
VII. Atmospheric Entry Heating of
Interplanetary Dust,
George J. Flynn
VIII. Extraterrestrial Material and Stratospheric
Aerosols,
Daniel M. Murphy
IX. Glacial Cycles and Interplanetary
Dust,
Richard A. Muller
X. Iridium and Osmium as Tracers of
Extraterrestrial Matter in Marine Sediments,
Bernhard
Peucker-Ehrenbrink
XI. Extraterrestrial Helium in Seafloor
Sediments: Identification,
Characteristics, and
Accretion Rate over Geologic Time,
Kenneth A. Farley
XII. Seeking Unbiased Collections of Modern and
Ancient Micrometeorites,
Susan Taylor and James
H. Lever
XIII. Cosmic Ray Exposure History of Meteorites,
Rainer Wieler and
Thomas Graf
XIV. Terrestrial Ages of Meteorites,
A. J. Timothy Jull
XV. Quantification of Meteorite Infall
Rates From Accumulations in Deserts,
and Meteorite
Accumulation on Mars,
Philip A. Bland
XVI. The Present-day Flux of Meteorites to the
Earth,
Ian Halliday
XVII. Fossil Meteorites,
Birger Schmitz and
Mario Tassinari
XVIII. The Sedimentary Record of Impact Events,
Christian Koeberl
XIX. The Terrestrial Cratering Record,
Richard A.F. Grieve
XX. The Lunar Record of Recent Impact
Cratering,
Jennifer A. Grier and
Alfred S. McEwen
XXI. Accretion to Earth and Moon 3.85 Ga,
Stephen J. Mojzsis and
Graham Ryder
XXII. Solar System Impact Rates Measured From Lunar
Spherule Ages,
Richard A. Muller,
Timothy A. Becker, Timothy S. Culler and Paul R. Renne
Birger Schmitz (Professor)
Marine Geology,
Earth Sciences Centre,
Box 460,
SE-405 30 Goteborg
Sweden
tel: +46-31-7734902
fax: +46-31-7734903
birger@gvc.gu.se
=============
(6) THE TERRIBLE LIZARD: THE FIRST DINOSAUR HUNTERS AND THE BIRTH
OF A NEW
SCIENCE
By Deborah Cadbury
Henry Holt & Company, Incorporated (2001)
http://shop.barnesandnoble.com/bookSearch/isbnInquiry.asp?sourceid=00001199495281216393&ISBN=0805067728&bfdate=01-06-2002+04:44:04
In this comprehensive narrative, Cadbury (Altering Eden) tells
the story of
the first fossilists, whose discoveries challenged the religious
convictions
of their day as they struggled with the implications of new
science. It
begins with Mary Anning, who unearthed the skeleton of a
monstrous creature beneath the cliffs of Dorset in 1812; Anning
would earn
the respect of her male peers, but not entry into their exclusive
societies.
Men like the eccentric Oxford don William Buckland sought to
reconcile the
biblical account of Noah's flood with the fossil record, while
the brilliant
Georges Cuvier posited a theory of "catastrophes" to
explain the progression
of life while still holding true to scripture.
The ambitious Richard Owen, who coined the term dinosaur and
claimed credit
for the discovery of dinosaurs, used his prestige to discount
early
evolutionary theories in favor of his own backward-looking
notions about a
biblical past. Unlike his rival Gideon Mantell, whose studies in
geology and
paleontology laid the foundation for the new science, Owen rarely
set foot
in a quarry or dig, but he did, according to Cadbury, mine his
share of
fellow scientists' works for ideas he then claimed as his own.
Cadbury makes
much of the rivalry between the two men, and to good effect. Her
focus on
Owen's injustices against Mantell, Owen's corresponding rise to
fame, and
Mantell's ultimately tragic end lends momentum to her narrative,
culminating
in the advent of the evolutionary idea with Darwin's On the
Origin of
Species. This is a must-read book for dinosaur enthusiasts, and
for anyone
who has ever wondered about the source of our present-day
assumptions and
unanswered questions about human origins.
>From the Publisher
"In 1812 a twelve-year-old girl named Mary Anning was
collecting fossils for
her father beneath the cliffs of Dorset when she discovered the
outline of a
lizardlike skeleton embedded in the limestone. Working with a
small hammer,
she unearthed a giant prehistoric animal seventeen feet
in length." "News of her discovery baffled scholars and
attracted the
attention of the Reverend William Buckland, and eccentric Oxford
naturalist
known for his interest in geology or
"undergroundology," as he called it.
Buckland eagerly used Mary's find and other remnant fossils to
set in motion
a quest to understand the world before Noah's flood, though his
inquiry was
in fact an attempt to prove the accuracy of the biblical record
(the
scriptures alone were the key to understanding history in his
view, and
fossils were interpreted in this context)." "Meanwhile,
another naturalist,
Gideon Mantell, a poor country doctor, uncovered giant petrified
bones in a
Sussex quarry and became obsessed with the ancient past that, he
came to
realize, must once have been teeming with creatures up to seventy
feet long.
Initially scorned by the scientific establishment, Mantell risked
his
reputation and career to reveal his vision of the lost world of
reptiles."
"Despite their efforts, it was the eminent anatomist Richard
Owen,
patronized by royalty, the prime minister, and the aristocracy,
who claimed
the credit for the discovery of the dinosaurs. Through guile,
political
intrigue, and brilliant scientific insight, Owen rose from a
surgeon's
apprentice in Lancaster to the highest echelons of society and
was feted as
the man who gave the extinct creatures their name, dinosaur, or
"terrible
lizard."" "Deborah Cadbury's lively story
re-creates the bitter feud between
Mantell and Owen, which drove one of them to despair and ruin and
secured
for the other unrivaled international acclaim. Their struggle
brought to
light the age of dinosaurs and created a new science that would
forever
change man's per
>From Kirkus Reviews
An absorbing account of the pioneer 19th-century British
geologists and
fossil collectors. Our hero is Gideon Mantell, of a noble family
long fallen
on hard times. The son of a shoemaker, Mantell was smitten with
fossils at
an early age. Without resources but recognized as a prodigy,
he was apprenticed to a surgeon and became a doctor in London.
For the rest
of his life he would balance his unenthusiastic practice of
medicine with a
passionate devotion to fossils. Enter one Mary Anning, who
supported her
family by gathering fossil "trinkets" from the
dangerous coastal cliffs of
Dorset to sell to tourists. Her keen eye led to her recognition
as a prime
"fossilist" among geologists and collectors, including
Mantell. One of her
major finds was the fossil remains of a giant sea lizard; little
by little, other huge
reptilian bones were unearthed by Mary and others, but not
without controversy.
Mantell waited years before the eminent Baron Cuvier in Paris
agreed that he
had found the remains of a huge herbivorous land reptile
(reversing his
earlier opinion that the fossil was mammalian). But the plot
thickened with
the appearance of the wicked Richard Owen, who rose
to pinnacles of power within the Royal Society and the Geological
Society,
became a social lion, and was an intimate of Queen Victoria and
Prince
Albert. At every step of the way he did his best to discredit and
ridicule
Mantell, at the same time claiming some of Mantell's fossils as
his own. His
comeuppance (and the recognition of Mantell's true worth) was the
result of
both his egregious behavior and his being on the wrong
(creationist) side of
the evolutionary debate as the scientific tide turned to
Darwinian theory.
"He liedfor God and for malice," an Oxford don
declared. "A bad case." A
scholarly account infused with a rare drama and suspense: read it
not only
for the science, but to learn what happened to all these
wonderful
characters.
=============
(7) DRAWING OUT LEVIATHAN: DINOSAURS AND THE SCIENCE WARS
By Keith M. Parsons
Indiana University Press (2001)
http://shop.barnesandnoble.com/bookSearch/isbnInquiry.asp?sourceid=00001199494847004704&ISBN=0253339375&bfdate=01-06-2002+04:50:24
>From the Publisher
" . . . Are dinosaurs social constructs? Do we really know
anything about
dinosaurs? Might not all of our beliefs about dinosaurs merely be
figments
of the paleontological imagination? A few years ago such
questions would
have seemed preposterous, even nonsensical. Now they must have a
serious
answer."
At stake in the "Science Wars" that have raged in
academe and in the media
is nothing less than the standing of science in our culture. One
side argues
that science is a "social construct," that it does not
discover facts about
the world, but rather constructs artifacts disguised as objective
truths.
This view threatens the authority of science and rejects
science's claims to
objectivity, rationality, and disinterested inquiry. Drawing Out
Leviathan
examines this argument in the light of some major debates about
dinosaurs:
the case of the wrong-headed dinosaur, the dinosaur
"heresies" of the 1970s,
and the debate over the extinction of dinosaurs.
Keith Parsons claims that these debates, though lively and
sometimes
rancorous, show that evidence and logic, not arbitrary
"rules of the game,"
remained vitally important, even when the debates were at their
nastiest.
They show science to be a complex set of activities, pervaded by
social
influences, and not easily reducible to any stereotype. Parsons
acknowledges
that there are lessons to be learned by scientists from their
would-be
adversaries, and the book concludes with some recommendations for
ending the
Science Wars.
About the Author:
Keith M. Parsons is Assistant Professor of Philosophy at the
University of
Houston, Clear Lake and author of God and the Burden of Proof. He
is editor
of Philo, Journal of the Society of Humanist Philosophers.
============================
* LETTERS TO THE MODERATOR *
============================
(8) SENATE NATURAL HAZARD CAUCUS AND OTHER NEAR-MISSES
>From Andy Smith <astrosafe@yahoo.com>
Hello Benny and CCNet,
Here are a couple of brief but important inputs.
U. S. Senate Natural Hazards Caucus
The level of this important activity is increasing.
Unfortunately,
asteroid/comet impact (ACI) is not yet on the list of credible
dangers and
we have been urging them to include it. David Applegate
( applegate@agiweb.org
) is the focal-point, at the American Geological
Institute (703-379-2480) and Peter Folger is the contact at the
American
Geophysical Union.
The Working Group is starting to organize a list of important
needs and
funding requirements, in
preparation for the next meeting of the Caucus, which is
co-chaired by
Senators Stevens and Edwards. It is important to communicate with
this key
caucus and to urge them to include the greatest of all credible
natural
disasters (ACI).
It is also important to let them know that the risk of the next
impact
(Tunguska or larger) is a disturbingly high 1 in 100 per year.
Finally, they
need to know how much more vulnerable the coastal cities are. We
urge all
CCNet members to contact these folks. The Caucus and the Working
Group have
good web pages that are easy to find.
Other Near-Misses
The Minor Planet Center (MPC) publishes an excellent list of NEO
near-misses, which shows that there have been 20 NEO approaches
which came
closer than the most recent 2001 YB5. Most of them are smaller
than a
kilometer and most were discovered in the last decade.
All are capable of wide-area destruction, loss-of-life and
suffering.
Because our search capability and global NEO data-base are so
limited, this
number may represent less than 1% of the actual near-misses (NM).
Jim Scotti
(SPACEWATCH) has suggested that there may be a near-miss every
half-hour.
This logic would suggest that there may have been more than
40,000 NM, in
the last ten years. The excellent NEO finding and follow-up
teams, around
the World, are extremely important and we need to find ways to
quickly reinforce their ranks.
This list underscores the fact that we are responding to the
wake-up call,
in 1989 (1989FC), and that is comforting. It also underscores the
need for
larger asteroid telescopes and for an orbiting search system, to
help with
the hunt. We sincerely appreciate what has been done by the Sloan
team and
we hope they will continue to help. We also emplore the other
"big guns" to
join-in.
This list also emphasizes the fact that we can deflect most of
the
intruders, using existing hardware--if we will just start some
serious
preparedness engineering. We should at least identify the
critical launcher,
spacecraft and deflection system components and be
sure they will fit and work-well, togeather and reduce the
critical
emergency response time from years to months, and week, if
possible.
We are urging the Caucus to support such an exercise (which
should be
international, in scope) and we are asking the new NASA/Langley
planetary
protection study effort to address it. We also want to thank our
Russian
colleagues, for the work they have done and continue to do, in
this area.
The MPC near-miss list is at:
http://cfa-www.harvard.edu/iau/lists/closest.html
Once again, we want to thank Brian Marsden and the MPC team, for
the
excellent job they are doing to provide us data and graphics, and
we
continue to value the CCNet for providing an excellent World
electronic
forum.
Cheers
Andy Smith
=============
(9) NUMERICAL MISQUOTES
>From David Morrison <dmorrison@arc.nasa.gov>
Benny:
You were quite correct to point out the two numerical misquotes
from me -- a
lesson to be more careful when giving numbers to the press, to
make sure we
are properly understood!
Dave
=============
(10) TSUNAMI FROM A 300m ASTEROID
>From Nigel Holloway <nigel.holloway@ukaea.org.uk>
Dear Benny,
I was a little surprised by Michael Paine's reassurance that had
2001 YB5
impacted an ocean the tsunami threat would have been relatively
short range,
encompassed by the blast range. He refers to his own paper on the
subject,
which in turn quotes estimates from three recent sources giving
quite a wide range of variation in deep ocean wave heights. For
example, for
200m and 500m objects the quoted deep ocean wave heights at a
1000 km range
are:
Source
200m object 500m object
Crawford & Mader
1998
~0 < 2 m
Hills & Goda
1999 1 (or
5) 11 m
Ward &
Ashphaug
5 15 m
Normally, when assessing risks and faced with a range of
estimates because
of uncertainty about the model, the 'conservative' thing to do is
to use the
worst case rather than the best - at least that's what we do in
the nuclear
industry. Although Crawford and Mader's estimates might turn out
to be the
right ones, the 'reassurance' given would not be at all possible
if either
of the other two were right.
Nigel Holloway
===============
(11) QUADRANTIDS DEBATE
>From Marco Langbroek <m.langbroek@rulpre.leidenuniv.nl>
Dear Benny,
In CCNet 5, Duncan Steel replies to my comment in CCNet 4 about
the age of
the Quadrantid shower. In this, he appears to ignore the true
content of our
paper in Astronomy & Astrophysics (A&A 327 (1997),
1242-1252).
The central argument of our paper is that the observed dispersion
in orbital
elements (i.e. inclination, perihelion and aphelion distance) for
meteoroids
in the Quadrantid shower is very small. It is too small, and the
orbital set
itself too structured, for the shower to have undergone the
evolutionary
trajectory which the models that link the shower to comet
Machholz imply.
Our estimate of 500 years at best as an age for the Quadrantids,
is based on
a direct comparison of the observed dispersion in the shower to
the
dispersion over time given by the model techniques that couple it
to
Machholz. Thus, if our assumptions are wrong (Steel's argument),
then so are
the assumptions behind the very models which Steel defends. If
the models
would be correct, then the observed radiant area and dispersion
in orbital
elements of Quadrantid meteors should have been wider than they
are in
reality, and they should not show the structuring which we
observed.
The dispersion in the Quadrantid orbits and radiants we gathered
is small by
any standard. It is small for example when compared to other
annual streams
like the Perseids or Geminids. Moreover, the data are structured:
they show
a number of interesting correlations between velocity and mass on
the one
hand, and radiant structure and orbital elements on the other
hand. Taken
all together, the suggestion really is that the stream is young,
as we point
out in our paper.
Steel wrote:
"Here I simply mention that rejection of the hypothesis that
96P/Machholz 1
is the parent for the Quadrantids implies that its fitting
against not only
the Quadrantids but also the other showers that the stream
produces is a
matter of chance, the likelihood of which is very slim. This
would
offend against William of Ockham (who of course is not
infallible)."
In answer to this, I want to point out that of the several (6,
8?) predicted
theoretical showers from comet Machholz, according to Jones &
Jones (to
which Steel refers) only 3 (Quadrantids, Arietids and delta
Aquarids) appear
to match observed showers. Of these 3, the match with one one
(Arietids) is
problematic, as Jones & Jones point out, leaving only the
delta Aquarids and
Quadrantids. We in turn question the relation with the
Quadrantids. This
leaves one stream (Aquarids) from the initial lot, with a second
(Arietids)
problematic. Will William of Ockham please stand up?!
Finally, for the benefit of the CCNet reader, I want to point out
that the
Quadrantid orbits of "this DMS group" (quod Steel) are
not only the most
accurate to date, but also one of the largest samples available.
Before we
added our 35 photographic and 29 video orbits, there were only 18
high
accuracy Quadrantid orbits in the IAU photographic meteor
database (and some
100 less accurate). Our dataset showed that what was thought to
represent
true intrinsic dispersal in the shower meteoroid orbits, in
reality is due
to unacknowledged inaccuracies in the orbital determinations, the
results of
our large set of orbits being much tighter constrained in radiant
positions
and orbital elements than the older sets of photographic orbits.
Kind regards,
Marco Langbroek
Dutch Meteor Society (DMS)
============
(12) WHAT MORE DO THEY WANT?
>From Jonathan Tate <fr77@dial.pipex.com>
Benny,
I am appalled by the announcement from Canada involving the
closure of the
Spaceguard Canada observation programme, even after an
endorsement from the
Canadian Space Agency's meteorites and impacts advisory
committee. After the
recent government Task Force in the UK that validated the impact
threat, to
hear of programme in a commonwealth country, and one as usually
enlightened
as Canada, having to close for lack of funding is simply
unbelievable! When
the penny is finally dropping all over the world, one would have
thought
that existing programmes would be getting increased support from
governments
proud to be in the forefront of events. (Mind you,
the accuracy of the reporting leaves something to be desired! The
establishment of a second information centre in the UK hardly
merits the
statement that "U.S. and British astronomers have been
improving efforts to
track potentially hazardous asteroids"! It may apply to the
US, but ..)
I am also interested (and almost encouraged) to hear about
developments in
Australia, but one is forced to ask the question "what more
do governments
need?" Administrations around the world, especially those
who consider
themselves to be more enlightened, can be under no illusion as to
the level
of risk posed to their employers (the electorate) by NEOs. If
they are, it
shows a deplorable lack of research by their civil servants, or a
complete
lack of understanding on the part of the elected officials. So I
ask them,
what more evidence do you want before you do something? Are we
going to have
to wait for an impact event to kill people before you act? Surely
that is
one of the lessons to come out of the tragic events in the USA of
September
last. There's no point in closing the stable door after the horse
has
bolted. The science community has unequivocally alerted
governments to the
hazard - it is hard to see how much clearer the message could be,
and full
responsibility for action has now passed to the politicians. The
excuse that
things take a long time to organise and co-ordinate is simply not
good
enough. There are numerous examples where governments have acted
speedily
and decisively when required to do so - with the proper
motivation
governments can work at speed. What more motivation to they need
before they
address the NEO hazard in a sensible fashion?
2001 YB5 is yet another "wake-up" call, but I am afraid
that our elected
representatives will probably continue to bury their heads in the
sand,
assuring the public that "studies" and conferences will
protect us from
hypervelocity lumps of rock and metal. It's a good thing
that they don't
apply the same criteria to bombs, bullets and jet aircraft.
Jay Tate
The Spaceguard Centre
=============
(13) SUPERNOVA I
>From Oliver Morton <abq72@pop.dial.pipex.com>
At 11:28 am +0000 9/1/02, Peiser Benny wrote:
(7) ANOTHER SCARE OR ANOTHER WORRY? "SUPERNOVA CAUSED MARINE
MASS EXTINCTION
2 MILLION YEARS AGO"
Odd headline, Benny: it's an interesting story, but neither a
scare nor a
worry. This should come as no surprise, as things don't have to
be one or
the other.
The idea that a supernova could do damage to the biosphere has
been around
since at least 1954, when Otto Schindewolf of Tubingen
University, a very
celebrated palaeontologist, suggested that a
supernova might account for the end permian extinction
("Uber die moglichen
Ursachen der grossen erdgeschichtlichen Faunenschnitte"
Neues Jahr. Geol.
Pal. vol10, 457). He revisited the idea in 1962
("Neokatastrophismus?"
Deutsch Geologische Gesellschaft Zeitschrift Jahrgang, 1962,
114,p.430-445)
and I'd be interested to know, if anyone on the list is in a
position to
clarify the matter, whether this is the earliest use of a cognate
of
"neocatastrophism", or whether it was already in use
(eg in "Worlds in
Collision"). In 1972 Russel and Tucker applied the same idea
to the K/T
("Supernovae and the Extinction of the Dinosaurs,"
Nature 229, 553); in 1974
Mal Ruderman put forth the cosmic-ray/ozone-depletion model for
how a
supernova at moderate distance might impact the biosphere
(Science, vol 184
1079) that is currently under discussion.
John Ellis and the late Dave Schramm looked at the issue again in
a general
way in 1993 (CERN preprint CERN-TH.6805/93), with a particular
interest in
the implications of the event that produced Geminga, a gamma ray
source
currently about 60pc away (I seem to recall hearing that Schramm
may have
been influenced by conversations with David Raup, a colleague at
Chicago and
key player in the K/T impact story). They returned to the topic,
with Brian
Fields, in 1996, (astro-ph/9605128) looking in more detail at the
radiogenic
markers that could be expected in ice and sediment cores. Fields
and Ellis
(astro-ph/9811457) looked at the Knie data that's the basis of
this latest
Benitez et al paper (astro-ph/0201018) and found it intriguing,
but could
see no obvious astrophysical candidate event that might serve as
a cause for
the Fe60 excursion. If the work by Benitez et al currently under
discussion
is right in suggesting a plausible nearby candidate at about 2Mya
that must
strengthen the case for such events a fair bit, and fine-scale
sedimentology
may clarify things further.
This looks like very interesting stuff. It could potentially
teach us about
a new mechanism for synchronised extinctions. If there turns out
to be
sedimentary evidence of a supernova-mediated ozone collapse but
it *doesn't*
coincide with the extinction, we could learn something about
biospheric
resilience. As Ellis, Schramm and Fields point out, we might even
learn
something new about supernovae, if we can tease out the remnants
in the
sediments in a useful way. But it is neither a scare nor a worry,
for the
simple reason that we can say with some assuredness that there
are no
just-about-to-be-supernova stars in our vicinity today.
Best for the new year, o
MODERATOR'S NOTE: Oliver, I agree; my headline was odd. But what
the heck.
Sometimes it is such wayward headlines that trigger an
enlightened and
interesting response. BTW: Here is what I found (in Trevor
Palmer's book
"Controversy: Catastrophism and Evolution", Kluwer,
1999, p. 106) about Otto
Schindewolf: "Schindewolf went on to discuss the idea [his
supernova mass
extinction idea] again in a 1963 article entitled
'Neokatastrophismus?',
which did not appear in English translation until 14 years later.
Because of
the title of the article, Schindewolf is very much associated
with the term
"neocatastrophism", although he did not invent it;
indeed, he remained
worried that it might suggest a link with the catastrophists of
earlier
times, and their supposedly unscientific attitudes." Perhaps
Trevor Palmer
can tell us more about the origins of the term
"neocatastrophism"?, BJP
==============
(14) SUPERNOVA II
>From Jonathan R. Ellis <John.Ellis@cern.ch>
Hi again Oliver,
I agree with what you say that we need not get nervous! Now I
have had a
chance to read the Benitez et al paper, and I am a little
disappointed that
they do not acknowledge the fact that (as far as I know) the late
Dave
Schramm and I originated the connection between supernovae and
plankton. I have written to them about this.
For your amusement, here is a short note summarizing some aspects
of the
timeline.
Cheers,
John
------
The idea that nearby supernova explosions might cause mass
extinctions is
not a new one: one of the most influential early papers was by
Ruderman in
1974. He specifically suggested that the most important effect
might be to
disrupt the Earth's ozone layer, a suggestion taken up by Ellis
and Schramm
in 1993. These authors further suggested that a very important
aspect of
this ozone depletion could be to kill plankton, with subsequent
knock-on
effects for other marine life. In 1996, the same authors together
with
Fields explored geological isotope signatures of nearby
supernovae in ice
cores and deep-ocean sediments (including Iron 60).
These papers were referred to by Knie et al in their 1998 paper
reporting an
indication for supernova-induced Iron 60 in deep-ocean sediments
in the
South Pacific. The interpretation of this signal was subsequently
considered, and more detailed calculations also for other
isotopes made by
Fields and Ellis in 1998.
M.A. Ruderman (1974) Science 184, 1079.
J. Ellis and D. Schramm (1993) hep-ph/9303206, published in the
Proc. Nat.
Acad. of Sciences (1995) 92, 235.
J. Ellis, B. Fields and D. Schramm (1996) astro-ph/9605128,
published in the
Astrophysical Journal (1996) 470, 1227.
K. Knie et al (1998) preprint, published in Phys. Rev. Lett.
(1999) 83, 18.
B. Fields and J. Ellis (1998) astro-ph/9811457, published in New
Astronomy
(1999) 4, 419.
=============
(15) SUPERNOVA III
>From Martin Barstow <mab@star.le.ac.uk>
Hi Benny,
I was very interested in Andrew Yee's item in yesterdays CCNET
circular.
(7) ANOTHER SCARE OR ANOTHER WORRY? "SUPERNOVA CAUSED MARINE
MASS EXTINCTION
2 MILLION YEARS AGO"
Andrew Yee <ayee@nova.astro.utoronto.ca>
I had a closer look at the abstract of the AAS paper. I cannot
comment
specifically on the detail of their work, but I believe that
there is a very
interesting tie in with work we did a few years ago on the local
interstellar medium (ISM) and, in particular, the ionization of
the
so-called local bubble. Perhaps you could include this in your
next email.
The gist of the story is this. Surveys of EUV and Soft X-ray
sources reveal
that the solar system resides in a low density cavity, roughly
50pc from the
centre (if taken to be roughly spherical), as discussed by
Warwick et al,
(1993, MNRAS, 262, 289). EUV spectra of white dwarfs lying in the
bubble
reveal that the intervening interstellar He is substantially
ionized (about
30%) and by implication (assuming a cosmic He/H ratio) so is the
hydrogen.
Work by Cheng and Bruhweiler (1990, ApJ, 364, 573) and Lyu and
Bruhweiler
(1996, ApJ, 459, 216) indicates that the level of
ionization observed cannot be explained by photo-ionization from
the
population of hot stars in the vicinity and that the ISM has
probably been
collisionally ionized by the blast wave from a supernova
explosion. Since
the effect of the shock wave is to completely ionize the gas
through which
it passes, the current ionization fraction, as the ions and
electrons
recombine, is essentially a measure of the time since the
explosion. In
1997, we published a survey of the He and H ionization in the
local ISM
(Barstow et al., 1997, MNRAS, 286, 58) finding it to be
effectively uniform
at 27% for He and 35% for H. This represents and elapsed time of
between 2
and 3.5 million years since the onset of the recombination phase,
since the
shock wave passed though the ISM.
It is intriguing that location (about 50pc away) and the
timescale
(2-3.5Myr) match the values reported by Benitez et al.
Best wishes,
Martin Barstow
---------------------------------------------------------------------------
Martin
Barstow,
Internet - mab@star.le.ac.uk
Dept of Physics &
Astronomy, WWW - http://www.star.le.ac.uk/~mab
University of
Leicester,
Phone +44 116 252 3492 (home 286 2330)
Leicester, LE1 7RH,
UK.
Fax +44 116 252 3311
=================
(16) STONEHENGE: AN EARLY IMPACT WARNING DEVICE?
>From Worth Crouch <doagain@jps.net>
Dear Dr. Peiser:
On January 8, 2002 Mr. Chichikov asked discussion group members
to share
with him speculations, meditations, hunches etc. concerning this
idea.
Consequently, I would like to contribute the little that I know
about
Stonehenge and the possibility that it was an early impact
warning device.
Many Native American's were quite interested in astronomy and the
predictability of asteroid or comet impacts. Among others the
Olmecs, Mayas,
Toltecs, and Aztecs all built observatories and devoted
considerable
resources to astronomy. I personally have visited ruins of
well-developed
observatories in the Yucatan and know that the three surviving
Aztec
codices, sheltered today in the Vatican, were concerned with
astronomy and
mathematics.
Below I offer my response, published June 5, 2001 in CCNet, to
Edward A.
Bryant's book TSUNAMI: THE UNDERRATED HAZARD. However, my
contribution to
Pavel Chichikov is even more "iffy" than my June
response to Bryant's book.
The speculation is that if the American Maritime Archaic were
able to
colonize parts of coastal Western Europe after a devastating NEO
ocean
impact. And if they brought their circular stone calendar
constructions
along with other megalithic type tombs and structures, then
Stonehenge could
have been an attempt to predict another devastating impact using
a gigantic
monolithic stone calendar.
If Mr. Chichikov is writing a novel my speculation certainly is
intriguing
especially if the Native American hero falls in love with a
surviving blond
British girl played by possibly Katie Price wearing her famous
Union Jack
Bikini.
Sincerely,
Worth F. Crouch (Talako)
Society of Choctaw Astrobiologists
cosmiccatastrophe.com
-----------
CCNet 6/5/01
Dear Dr. Peiser:
I was pleased to read the May 31, 2001 extract taken from Edward
A. Bryant's
new book TSUNAMI: THE UNDERRATED HAZARD. For many years I have
been a
proponent of the historical and anthropological evidence
indicating a
maritime seafaring people from America, that built megalithic
type tombs and
structures, discovered and inhabited parts of coastal Europe
about 7000
years ago. However, a question has remained in my mind even
though evidence
gathered by Dr. William Fitzheau of the Smithsonian Institute in
1980, and
Erich Brinch Petersen of the Danish National Museum indicate
American
Maritime Archaic people probably migrated to Europe at least 7200
years ago.
I have always questioned how the Maritime Archaic, or Red Paint
People as
they were called by the American anthropologist Dr. Moorhead,
were able to
get a foothold in a Europe composed of folks with a different
complexion,
culture, and competing for similar resources. I know the Norsemen
or Vikings
tried to colonize America for at least 200 years without success
and were
eventually stopped by Native Americans. Moreover, Norse
technology in AD 800
-1000 was superior to the Native American's as well as the
earlier Maritime
Archaic technology. Until now I have wondered how the Red Paints
could
colonize even a few sights on the European coast successfully
considering
the Maritime Archaic in Europe, like the Vikings in America, must
have been
terribly outnumbered. Evidence from excavations in Nuilliak Cove
Labrador,
Vedbaek Norway, Port au Cvhoix Newfoundland, Teviec Brittany,
L'Anse Amour
Newfoundland, and Muge Portugal all indicate the communities were
probably
populated by Red Paint People. The oldest Maritime Archaic sight
in Europe
is Teviec prospering about 7200 years ago, off the coast of
Brittany in
France, and the artifacts, method of burial, artistic designs,
and evidence
of shamanistic rituals of the Maritime Archaic in Europe are
amazingly
similar to the other Red Paint sights in America.
The purpose of this correspondence is not to argue the merits of
the Red
Paint People's claim to Europe, but instead to use information
from Edward
A. Bryant's new book and answer my previously unanswered
question. He
writes, "One of the more disturbing accounts has been
compiled from these
legends by Edith and Alexander Tollmann of the University of
Vienna, who
believe that a comet circling the sun fragmented into seven large
bodies
that crashed into the world's oceans 8,200 ± 200 years ago. This
age is
based on radiocarbon dates from Vietnam, Australia and Europe.
The impacts
generated an atmospheric fireball that globally affected society.
This was
followed by a nuclear winter characterised by global cooling.
More
significantly, enormous tsunami swept across coastal plains and,
if the
legends are to be believed, overwashed the centre of continents.
The latter
phenomenon, if true, most likely was associated with the splash
from the
impacts rather than with conventional tsunami run-up. Massive
floods then
occurred across continents. The event may well have an element of
truth.
Figure 8.9 plots the location of the seven impact sites derived
from
geological evidence and legends. Two of these sites, in the
Tasman and North
Seas, have been identified as having mega-tsunami events around
this time.
The North Sea impact centre corresponds with the location of the
Storegga
slides described in Chapter 6. Here, the main tsunami took place
7,950 ±190
years ago."
If the before mentioned information in Bryant's book is correct
it would
explain why the Red Paints did not face a formidable European
population
opposing their coastal colonization. In fact the coastal European
population
would have been washed away by the results of a comet's North Sea
impacting
tsunami 700 years before the Red Paints discovered Europe. Also
if the
actions of New Zealand Aboriginal Coastal tribes surviving a
comet's
resulting tsunami in AD 1178, can be superimposed on those
Europeans
surviving the resulting North Sea tsunami around 7950 years ago
the
Europeans would probably have avoided the coast as did the New
Zealand
Aboriginals for hundreds of years. Thus, allowing the Red Paints
to colonize
without much opposition, and build their fragile coastal
communities along
with their sturdy megaliths, the origins of which continue to
frustrate
future generations of historians.
Sincerely,
Worth F. Crouch
===========
(17) AND FINALLY: SCIENTISTS TO STUDY GIANT ASTEROIDS - BY
STEERING THEM INTO EARTH
Are Major Asteroid As Dangerous As
Predicted? The Answer Arrives in 2003
London (SatireWire.com) - Disappointed after failing to take
advantage of
Earth's relatively near miss with a large asteroid on Monday,
scientists
today excitedly unveiled what they called an "asteroid
chute" that they said
will direct the next massive space object directly into Earth's
path, where
it can be studied more closely.
POTENTIAL OUTCOMES
"We don't know what will happen," said one NASA
astrophysicist. "It's all so
very exciting." Scientists hope the redirected asteroid, now
expected to
strike Earth by June of 2003, will also settle a pair of
long-running
debates: Did an asteroid cause the extinction of the dinosaurs 65
million
years ago? And what size must an asteroid be in order for it to
render a
planet uninhabitable?
According to Michael Banio of Great Britain's Royal Astronomical
Society,
asteroid "2001 YB5" passed within 375,000 miles of
Earth on Monday, but it
was still too far away for useful studies to be conducted. And
because YB5
was not discovered until December, scientists did not have time
to prepare
for its arrival. However, using electron particle impulses
emitted by a
modified NASA satellite early this morning, British and American
astrophysicists said they successfully nudged the next asteroid,
a
kilometer-wide giant they've labeled 2002 CUL8R, directly into
Earth's path.
Asked what impact CUL8R will have, NASA astrophysicist Karen Lurg
excitedly
hesitated to speculate.
"Well, we're not sure, and that's the beauty of it,"
she said. "What we
think will happen is, the ECO (Earth Crossing Object), which most
likely has
an iron/nickel core, will slam into Earth with the force of
roughly 1
million nuclear bombs. But now we'll be able to test that
hypothesis."
"The 1 million nuclear bombs is an average postulation, by
the way," she
added. "Some say 2 million. Others, believe it or not, say
only 15,000. I
think those folks are going to have egg on their faces when it's
all said
and done."
The non-scientific community, however, failed to share Lurg's
interest.
Moments after the announcement, the United Nations Security
Council demanded
that CUL8R be directed away from Earth immediately, and dozens of
international leaders called the chute "catastrophically
irresponsible" and
"just bad science."
Scientists were quick to label the reaction "typical
laymen's myopia."
"Every 10 million years, an object at least 1km across
smashes into Earth,
so it's inevitable that someday it's going to happen," said
Banio. "By
steering such objects toward us now and studying the results
close up, we
will be better prepared for that eventuality."
Meanwhile, Heinrich Voom, director of the Los Alamos National
Laboratory, bristled at the charges of capriciousness. "Far
from being
irresponsible, we plan to strictly adhere to the Scientific
Method; that is:
Observe. Hypothesize. Predict. Test. Repeat until there are no
discrepancies
left," he said.
"It's the 'no discrepancies left' part that bothers
me," countered U.S.
Homeland Security Director Tom Ridge.
Voom acknowledged that CUL8R may not settle every question. Three
years ago,
scientists at Los Alamos predicted an asteroid three miles across
that
strikes the mid-Atlantic Ocean would produce a tidal wave that
would cover
the East Coast of the United States to the Appalachian Mountains.
It would
also envelop the coasts of France and Portugal. Voom conceded
CUL8R is not
large enough to adequately test this model. However, he insisted,
even a
small tidal wave that only destroys Portugal would be useful in
devising
further experiments with the asteroid chute.
Portuguese President Jorge Sampaio, however, said he would rather
the model
remain in the hypothetical stage. "I do not want to be a
resolved
discrepancy," he said.
Sampaio added that if the asteroid must come, he wished it would
come now
and "get it over with," but Voom said the rock should
not be rushed.
"If we were to increase the asteroid's speed, we would not
have enough time
to apply for several multi-million-dollar grants we'll need to
study its
impact," he explained. "That is what I would call bad
science."
Copyright © 1999-2002, SatireWire.
>From http://www.satirewire.com/news/jan02/asteroid.shtml
------------------------------------------------------------------------
SatireWire is intended for use by those age 18 and older. All
stories
are fictional and satirical and should not in any way be
construed as fact.
Please read our disclaimer. All contents Copyright © 1999-2002,
SatireWire, LLC. All rights reserved.
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*
CCNet SPECIAL: 2001 YB5 SCHLAEGT EIN IN DEUTSCHEN MEDIEN:
BERICHTERSTATTUNG
& REAKTIONEN
----------------------------------------------------------------------------
------------
MODERATOR'S NOTE: This special CCNet edition has been compiled by
Christian
Gritzner (Dresden University of Technology) and myself. It
documents the
level of increased media interest about the impact hazard and
ongoing NEO
research in Germany. It is addressed to our German-speaking
members on
CCNet. Apologies to all the others, and many thanks to Christian
for his
assistance. BJP
-------------------
"Das hätte schief gehen können. Die meisten Bewohner der
Erde waren
ahnungslos, als am Montag ein Himmelskörper - ein so genannter
Asteroid
- mit einem Durchmesser von 300 Metern an diesem Planeten knapp
vorbeisauste.... Da wird es langsam Zeit, dass sich
Internationale
Organisationen Gedanken über eine Abwehr machen."
--Andreas Oswald, Der Tagesspiegel, 9. Januar 2002
«2001 YB5» war unter anderem von den tschechischen
Sternforschern
Jana Ticha und Milos Tichy beobachtet worden. «Der Asteroid war
sehr sehr
nahe», sagte Ticha. Lenka Sroubkova vom Planetarium in Oldrichov
(Mittelböhmen) sagte, «die hohe Geschwindigkeit des Asteroids
löst im
Observatorium eine automatische Kamera aus - das ist das gleiche
Prinzip,
das ein Polizei-Radar bei Rasern benutzt». Im Jahr 2027 werde
der
ein Kilometer große Asteroid «1999 AN10» sogar noch näher an
der Erde
vorbeirasen."
--Deutsche Presse Agentur, 8. Januar 2002
"Treffe ein Asteroid von 300 Metern Durchmesser auf die
Erde, würde
er einen Krater von ungefähr sechs Kilometern Durchmesser
schlagen,
erläuterte Raumfahrtingenieur Christian Gritzner von der
Technischen
Universität Dresden. Im Umkreis von 50 bis 100 Kilometern gäbe
es schwerste
Zerstörungen durch Trümmer und Erdbeben. Unabsehbar seien die
Folgen, falls
Kernkraftwerke oder Chemieanlagen betroffen seien. Ein Einschlag
ins Meer
könne tatsächlich zu Flutwellen wie im Film «Deep Impact»
führen,
erläuterte Asteroiden-Experte Gritzner. Generell gehe von diesen
Brocken eine Gefahr für die Erde aus."
--Deutsche Presse Agentur, 8. Januar 2002
"Ein langer einschlagsbedingter Winter, wie er einst zum
Aussterben
der Dinosaurier geführt haben soll, wäre aber nicht zu
befürchten
gewesen. "Dazu war er nicht groß genug", sagt Gerhard
Hahn,
wissenschaftlicher Mitarbeiter des Instituts für
Weltraumsensorik und
Planetenerkundung in Berlin-Adlershof. Dieses Institut ist das
einzige, das
in Deutschland die Gefahr durch Himmelskörper beobachtet und
untersucht.
"Am größten ist die Wahrscheinlichkeit, dass ein Asteroid
ins Meer
fällt. Dann drohen Riesenwellen, die auf die Küsten zurasen
würden", sagt
Hahn. Sie könnten sich je nach Küstenbeschaffenheit bis zu 100
Meter
auftürmen und große Verwüstungen verursachen. Bilder wie in
dem
Katastrophenstreifen "Deep Impact" könnten durchaus
der Realität
entsprechen. Da wird es langsam Zeit, dass sich Internationale
Organisationen Gedanken über eine Abwehr machen."
--Der Tagesspiegel, 9. Januar 2002
(1) ASTEROID FLY-BY TRIGGERS MEDIA INTEREST IN GERMANY
Christian Gritzner <christian.gritzner@mailbox.tu-dresden.de>
(2) 300 METER GROSSER ASTEROID RAST AN DER ERDE VORBEI
Yahoo.de, 8. Januar 2002
(3) RIESEN-ASTEROID RAST AN ERDE VORBEI
focus.de, 8. Januar 2002
(4) BEINAHE-KOLLISION - Asteroid verfehlte Erde knapp
Spiegel Online, 7. Januar 2002
(5) METEORIT RASTE AN DER ERDE VORBEI
sueddeutsche.de, 7. Januar
2002
(6) KNAPP DANEBEN
netzeitung.de, 7. Januar 2002
(7) 300 METER GROSSER ASTEROID RAST AN DER ERDE VORBEI
Die Welt, 8. Januar 2002
(8) SZENARIEN, DIE FURCHT EINFLOESSEN: Forscher studieren
frühere Einschläge
Bremer Nachrichten, 9. Januar 2002
(9) ASTEROID FLIEGT NAHE AN ERDE VORBEI
Frankfurter Allgemeine Zeitung, 7. Januar 2002
(10) DAS WAR KNAPP
Der Tagesspiegel, 9. Januar 2002
(11) KOSMISCHE HAARESBREITE: DAS FRUEHWARNSYSTEM HAT VERSAGT
Der Tagesspiegel, 9. Januar 2002
(12) DIE ERDE SCHRAMMT KNAPP AM CRASH VORBEI
Die Tageszeitung, 9. Januar 2002
==================
(1) ASTEROID FLY-BY TRIGGERS MEDIA INTEREST IN GERMANY
>From Christian Gritzner <christian.gritzner@mailbox.tu-dresden.de>
Dear Benny,
The fly-by of asteroid 2001 BY5 caused a lot of media interest in
Germany,
too. Please find attached some German articles that I have
discovered in the
www. Some articles are based on the dpa (deutsche Presse-Agentur)
news.
Best wishes,
Christian
Dresden University of Technology
Institute for Aerospace Technology
Dr.-Ing. Christian Gritzner, Senior Engineer
D-01062 Dresden, Germany
Please note my new phone number:
phone: +49-(0)351-463-38234 (Fax: -38126)
E-mail: christian.gritzner@mailbox.tu-dresden.de
Homepage: www.tu-dresden.de/mw/ilr/space/space.htm
===============
(2) 300 METER GROSSER ASTEROID RAST AN DER ERDE VORBEI
Yahoo.de: http://de.news.yahoo.com/020108/3/2irdd.html
Dienstag 8. Januar 2002, 11:58 Uhr
300 Meter großer Asteroid rast an Erde vorbei
Pasadena/Oldrichov (dpa) - Ein Asteroid mit einem Durchmesser von
300 Metern
ist am Montag knapp an der Erde vorbeigerast. Der mehr als 100000
Kilometer
pro Stunde schnelle Himmelskörper «2001 YB5» sei mit 833000
Kilometern nur
etwa doppelt so weit entfernt gewesen wie der Mond, berichtete
Donald
Yeomans vom Jet Propulsion Laboratory der NASA in Pasadena
(Kalifornien).
Objekte
dieser Größe kämen nur alle paar Jahre der Erde derart nahe.
Er würde diesen
Asteroid nicht als
gefährlich bezeichnen, aber als interessant, sagte Yeomans.
«2001 YB5» war unter anderem von den tschechischen
Sternforschern Jana Ticha
und Milos Tichy beobachtet worden. «Der Asteroid war sehr sehr
nahe», sagte
Ticha. Lenka Sroubkova vom Planetarium in Oldrichov
(Mittelböhmen) sagte,
«die hohe Geschwindigkeit des Asteroids löst im
Observatorium eine automatische Kamera aus - das ist das gleiche
Prinzip,
das ein Polizei-Radar bei Rasern benutzt». Im Jahr 2027 werde
der ein
Kilometer große Asteroid «1999 AN10» sogar noch näher an der
Erde
vorbeirasen.
Treffe ein Asteroid von 300 Metern Durchmesser auf die Erde,
würde er einen
Krater von ungefähr sechs Kilometern Durchmesser schlagen,
erläuterte
Raumfahrtingenieur Christian Gritzner von der Technischen
Universität
Dresden. Im Umkreis von 50 bis 100 Kilometern gäbe es schwerste
Zerstörungen
durch Trümmer und Erdbeben. Unabsehbar seien die Folgen, falls
Kernkraftwerke oder Chemieanlagen betroffen seien. Ein Einschlag
ins Meer
könne tatsächlich zu Flutwellen wie im Film «Deep Impact»
führen, erläuterte
Asteroiden-Experte Gritzner. Generell gehe von diesen Brocken
eine Gefahr
für die Erde aus.
Eine globale Katastrophe könne ein Asteroid von einem Kilometer
Durchmesser
auslösen. «Es ist nur eine Frage der Zeit, bis das nächste
derart große
Objekt die Erde direkt trifft», erläuterte Gritzner. Ein
Asteroid von einem
Kilometer Durchmesser schlage statistisch gesehen alle 300000
Jahre in die
Erde ein. «Demnach gibt es ein Risiko von 1:3000, dass wir in
den nächsten
100 Jahren durch Asteroiden eine globale Katastrophe bekommen,
mit
Klimaänderungen und Missernten». Der Asteroid, der vor rund 65
Millionen
Jahren die Dinosaurier ausgelöscht hatte, sei zehn Kilometer
groß gewesen.
Der nächste bereits bekannte Asteroid von ähnlicher
Größenordnung und
Entfernung zur Erde soll laut NASA am 2. Weihnachtsfeiertag 2011
an der Erde
vorbeirasen. «2000 YA» wird dann von der Erde rund drei Mal so
weit entfernt
sein wie der Mond. Insgesamt beobachtet die NASA derzeit 363
potenziell gefährliche Asteroiden. Als potenziell gefährlich
gelten
Gesteinsbrocken, die größer als etwa 150 Meter sind und der
Erde näher als
etwa 7,5 Millionen Kilometer (etwa 20-fache Mondentfernung)
kommen.
Internet: Homepage des JPL-Near-Earth-Objects-Programm:
http://neo.jpl.nasa.gov/
==========
(3) RIESEN-ASTEROID RAST AN ERDE VORBEI
focus.de: http://focus.de/G/GN/gn.htm?snr=99979&streamsnr=9
Riesen-Asteroid rast an Erde vorbei
Gefährlich nah ist ein Asteroid mit einem Durchmesser von 300
Metern der
Erde gekommen. Der Himmelskörper namens "2001 YB5" sei
mit 833 000
Kilometern nur etwa doppelt so weit entfernt gewesen wie der
Mond, teilte
die US-Raumfahrtbehörde Nasa am Montag mit. Objekte dieser
Größe kämen nur
alle paar Jahre der Erde derart nahe. Der Asteroid sei erst
vor wenigen
Wochen entdeckt worden.
Wenn ein Asteroid von dieser Größe auf die Erde träfe, so
würde er einen
Krater von ungefähr sechs Kilometern Durchmesser schlagen,
erläuterte
Raumfahrtingenieur Christian Gritzner von der Technischen
Universität
Dresden. Im Umkreis von 50 bis 100 Kilometern wären schwerste
Zerstörungen
durch Trümmer und Erdbeben die Folge. Unabsehbar seien die
Folgen, falls
Kernkraftwerke oder Chemieanlagen betroffen wären. Und ein
Einschlag ins
Meer könne tatsächlich zu Flutwellen wie im Film "Deep
Impact" führen, sagte
Gritzner.
07.01.02, 19:33 Uhr
===========
(4) BEINAHE-KOLLISION - Asteroid verfehlte Erde knapp
spiegel.de: http://www.spiegel.de/wissenschaft/0,1518,175808,00.html
BEINAHE-KOLLISION - Asteroid verfehlte Erde knapp
In kurzer Entfernung hat ein Asteroid am Montag die Erde
passiert. Die
Begegnung mit dem Felsbrocken, der bei einem Volltreffer ein
ganzes Land
hätte auslöschen können, betrachten Astronomen als Warnung. In
astronomischen Begriffen verlief das Rendezvous, das die Erde am
Montag ohne Schaden überstand, äußerst eng: Ein Asteroid von
etwa 300 Metern
Größe passierte den Planeten um 8.37 Uhr MEZ in einer
Entfernung, die etwa
dem doppelten Abstand zwischen Erde und Mond entspricht. Zwar
bestand für
die Menschheit keine Gefahr, Astronomen nutzen jedoch die
Gelegenheit, um
vor der Gefahr aus dem Weltraum zu warnen. Besorgnis
erregend ist vor
allem, dass der Himmelkörper, dessen stark elliptische Bahn die
von Mars,
Erde, Venus und Merkur schneidet, erst im Dezember entdeckt
wurde. Das
Objekt mit dem Namen 2001 YB5, das die Sonne einmal in 1321 Tagen
umkreist,
war Anfang des Monats Asteroidenjägern des Suchprogramms Neat
(Near Earth
Asteroid Tracking) aufgefallen.
Dass der Fund erst kurz vor der Annäherung an die Erde gelang,
gibt
Astronomen zu denken. Die späte Entdeckung führe zu der Frage,
"ob wir
genügend Zeit zum Handeln gehabt hätten, wenn sich das Objekt
auf einem
Kollisionskurs befunden hätte", sagte Benny Peiser von der
Liverpool
John Moores University gegenüber "BBC News Online".
Die Antwort steht für
den Forscher bereits fest: "Natürlich nicht, wir hätten
nichts daran ändern
können."
Bei einem Einschlag hätte 2001 YB5 wohl nicht die gesamte
Menschheit
ausgelöscht - um solch eine Energie freizusetzen, müsste das
Einschlagsobjekt etwa einen Kilometer Durchmesser besitzen.
Allerdings würde
auch schon ein 300-Meter-Felsbrocken fürchterliche Verwüstungen
anrichten:
Wie Astronomen vermuten, könnte ein solches Geschoss ein
gesamtes Land
vernichten, wobei es noch in über 800 Kilometer Entfernung
schwere Schäden
hervorrufen würde. Gebannt ist die Gefahr eines solchen
Aufpralls nicht:
2001 YB5 könnte, so spekulieren die Forscher, der Erde in
Zukunft noch
einmal gefährlich werden, auch wenn das Risiko dafür relativ
gering ist.
Dennoch haben
ähnlich große Himmelskörper die Erde in der Vergangenheit
vermutlich schon
häufig getroffen. Im Schnitt kommt es alle
5000 Jahre zu einer Kollision mit einem 300-Meter-Objekt, so die
grobe
Schätzung der Wissenschaftler. Auch eine lebensauslöschende
Katastrophe
durch ein mindestens kilometergroßes Einschlagsobjekt ist für
Astronomen nur
eine Frage der Wahrscheinlichkeit: Nach neuesten Hochrechnungen
betragen die
Chancen, dass so ein Felsen in den nächsten hundert Jahren auf
die Erde
prallen wird, eins zu 5000.
Derartige Prognosen sind zwar kein Grund, in Panik zu verfallen.
Forscher
halten es jedoch für nötig, Vorsorgemaßnahmen zu
ergreifen. Für Peiser ist
die spät bemerkte Annäherung von 2001 YB5 deshalb ein
Warnzeichen: "Sie
erinnert uns daran, was passieren könnte, wenn wir
Asteroiden nicht genauer
überwachen und bessere Vorbereitungen treffen, um unseren
Planeten zu
schützen."
===========
(5) METEORIT RASTE AN DER ERDE VORBEI
sueddeutsche.de:
http://www.sueddeutsche.de/index.php?url=/wissenschaft/naturwissenschaft/33757&datei=index.php
07.01.2002 14:38
Meteorit raste an der Erde vorbei: Das Himmelgeschoss hatte 300
Meter
Durchmesser und wurde erst im Dezember entdeckt.
Ein Meteorit, den die Astronomen erst im vergangenen Monat im All
entdeckt
haben, raste heute morgen um 7.57 Uhr mitteleuropäischer Zeit an
der Erde
vorbei. Die Entfernung entsprach nur zweimal der Distanz zwischen
dem Mond
und unserem Planeten, meldet der Online-Dienst des
britischen Nachrichtensenders BBC. Das ist nach kosmischen
Maßstäben sehr
knapp. Wissenschaftler nehmen das Ereignis zum Anlass, auf die
mögliche
Gefahr, die der Erde durch Meteoriteneinschläge drohen könnte,
hinzuweisen.
300 Meter Durchmesser
Astronomen von NEAT (Near Earth Asteroid Tracking), das dem
amerikanischen
Jet Propulsion Laboratory in Pasadena im Kalifornien
angeschlossen ist,
haben den Meteoriten im Dezember entdeckt. Sie sprechen von einem
"Apollo-Objekt". Denn der Meteorit, der als 2001 YB5
bezeichnet wird, hat
eine stark elliptische Bahn, die die Flugbahnen von Mars, Erde,
Venus und
Merkur kreuzt. Er umrundet die Sonne alle 1,321 Tage.
Großes Zerstörungspotential
Tschechische Forscher vom Klet Observatorium in Ceske Budejovice
haben den
Meteoriten während seines Flugs an der Erde vorbei beobachtet.
2001 YB5 hat
ungefähr 300 Meter Durchmesser und hätte, wenn es zu einem
Aufprall gekommen
wäre, ein ganzes Land auslöschen können, heißt es bei BBC.
150 Kilometer im
Umkreis wäre alles dem Erdboden gleichgemacht worden. Noch bis
800 Kilometer
um den Einschlagsort wäre alles stark verwüstet gewesen. Ein
Aufprall in
einem Ozean hätte Flutwellen verursachen können, die eine
verheerende
Wirkung auf Küstenstädte haben.
Was die Statistik sagt
Wissenschaftler weisen nun darauf hin, dass laut Statistik alle
5000 Jahre
ein Meteorit der Größenordnung von 2001 YB5 auf die Erde
treffen könnte. Das
sei jedoch eine Annahme, die sich in historischer Zeit nicht
bestätigt habe.
(sueddeutsche.de/BBC)
=======
(6) KNAPP DANEBEN
netzeitung.de:
http://www.netzeitung.de/servlets/page?section=5681&item=173633
Knapp daneben, 07. Jan 10:53
Ein 300 Meter großer Asteroid hat die Erde nur knapp verfehlt.
In Zukunft
könnte er zu einer Gefahr für unseren Planeten werden.
Von Thomas Trösch
Es war ein knappe, aber ungefährliche Begegnung: In den
Morgenstunden des
heutigen Montag passierte der Asteroid 2001 YB5 die Erde in knapp
600.000
Kilometern Distanz - für kosmische Maßstäbe weniger als ein
Steinwurf. Der
Asteroid war erst Anfang Dezember letzten Jahres entdeckt
worden. Mit einer Größe von 300 Metern hätte er bei einem
Einschlag auf der
Erde ein Gebiet von der Größe der Bundesrepublik komplett
verwüstet.
Überraschung im Dezember
Astronomen des Observatoriums auf dem kalifornischen Mount
Palomar hatten
2001 YB5 bei einer Durchmusterung im Rahmen des NEAT-Projekt(Near
Earth
Asteroid Tracking) entdeckt. Berechnungen ergaben, dass sich der
Asteroid
auf einer Umlaufbahn um die Sonne befindet, die ihn in 1321 Tagen
einmal um
unser Zentralgestirn führt. Dabei kreuzt er die Bahnen von
Merkur, Venus,
Erde und Mars.
Schnell war den Astronomen klar, dass der Asteroid unserer Erde
extrem nahe
kommen würde - weniger als die doppelte Monddistanz. Solche
nahen
Begegnungen sind recht selten. Eigentlich rechneten die
Astronomen erst für
August 2027 mit einem derartigen Ereignis. Dann wird sich der
Asteroid 1999 AN 10 ähnlich nah an die Erde heranarbeiten. Doch
das
Auftauchen von 2001 YB5 zeigt, mit welchen Überraschungen die
Asteroidenforscher rechnen müssen.
«Potenziell gefährlich»
Zwar sind weltweit zahlreiche Teleskope auf der Suche nach
kleinen Objekten
in Erdnähe, die unserem Planeten gefährlich werden könnten.
Wegen ihrer
geringen Größe und ihren oft exzentrischen Umlaufbahnen sind
solche Objekte
jedoch nur schwer zu entdecken. Und auch bei einer
Sichtung bleibt die Frage, ob sich im Falle eines
Kollisionskurses überhaupt
etwas tun ließe.
Im Falle von 2001 YB5 etwa lautet die Antwort «Nein» - so die
knappe
Einschätzung von Benny Peiser von der Universität Liverpool in
einem
Gespräch mit der BBC. Der Asteroid wird denn auch von Astronomen
als
«potenziell gefährlich» eingestuft. Schon eine kleine
Änderung seiner Bahn
könnte ihn zur Gefahr für die Erde werden lassen. Etwa alle
5000 Jahre, so
die Schätzung von Astronomen, wird unser Planet von einem Objekt
in der
Größe von 2001 YB5 getroffen. Grund genug, den Asteroiden und
ihrer
möglichen Bekämpfung auch in Zukunft besondere Aufmerksamkeit
zu widmen.
===========
(7) 300 METER GROSSER ASTEROID RAST AN DER ERDE VORBEI
welt.de:
www.welt.de/wissenschaft/
(siehe: news ticker, 8.1.02)
300 Meter großer Asteroid rast an Erde vorbei
Pasadena/Oldrichov (dpa) - Ein Asteroid mit einem Durchmesser von
300 Metern
ist am Montag knapp an der Erde vorbeigerast. Der mehr als 100
000 Kilometer
pro Stunde schnelle Himmelskörper «2001 YB5» sei mit 833 000
Kilometern nur
etwa doppelt so weit entfernt gewesen wie der Mond, berichtete
Donald
Yeomans vom Jet Propulsion Laboratory der NASA in Pasadena
(Kalifornien).
Objekte dieser Größe kämen nur alle paar Jahre der Erde derart
nahe. Er
würde diesen Asteroid nicht als gefährlich bezeichnen, aber als
interessant,
sagte Yeomans.
«2001 YB5» war unter anderem von den tschechischen
Sternforschern Jana Ticha
und Milos Tichy beobachtet worden. «Der Asteroid war sehr sehr
nahe», sagte
Ticha. Lenka Sroubkova vom Planetarium in Oldrichov
(Mittelböhmen) sagte,
«die hohe Geschwindigkeit des Asteroids löst im Observatorium
eine
automatische Kamera aus - das ist das gleiche Prinzip, das ein
Polizei-Radar
bei Rasern benutzt». Im Jahr 2027 werde der ein Kilometer große
Asteroid
«1999 AN10» sogar noch näher an der Erde vorbeirasen.
Treffe ein Asteroid von 300 Metern Durchmesser auf die Erde,
würde er einen
Krater von ungefähr sechs Kilometern Durchmesser schlagen,
erläuterte
Raumfahrtingenieur Christian Gritzner von der Technischen
Universität
Dresden. Im Umkreis von 50 bis 100 Kilometern gäbe es schwerste
Zerstörungen durch Trümmer und Erdbeben. Unabsehbar seien die
Folgen, falls
Kernkraftwerke oder Chemieanlagen betroffen seien. Ein Einschlag
ins Meer
könne tatsächlich zu Flutwellen wie im Film «Deep Impact»
führen, erläuterte
Asteroiden-Experte Gritzner. Generell gehe von diesen Brocken
eine Gefahr
für die Erde aus.
Eine globale Katastrophe könne ein Asteroid von einem Kilometer
Durchmesser
auslösen. «Es ist nur eine Frage der Zeit, bis das nächste
derart große
Objekt die Erde direkt trifft», erläuterte Gritzner. Ein
Asteroid von einem
Kilometer Durchmesser schlage statistisch gesehen alle 300 000
Jahre in die
Erde ein. «Demnach gibt es ein Risiko von 1:3000, dass wir in
den nächsten
100 Jahren durch Asteroiden eine globale Katastrophe bekommen,
mit
Klimaänderungen und Missernten». Der Asteroid, der vor rund 65
Millionen
Jahren die Dinosaurier ausgelöscht hatte, sei zehn Kilometer
groß gewesen.
Der nächste bereits bekannte Asteroid von ähnlicher
Größenordnung und
Entfernung zur Erde soll laut NASA am 2. Weihnachtsfeiertag 2011
an der Erde
vorbeirasen. «2000 YA» wird dann von der Erde rund drei Mal so
weit entfernt
sein wie der Mond. Insgesamt beobachtet die NASA derzeit 363
potenziell
gefährliche Asteroiden. Als potenziell gefährlich gelten
Gesteinsbrocken,
die größer als etwa 150 Meter sind und der Erde näher als etwa
7,5 Millionen
Kilometer (etwa 20-fache Mondentfernung) kommen.
Internet: Homepage des JPL-Near-Earth-Objects-Programm:
http://neo.jpl.nasa.gov/
11:58 am 08.01.2002 - Ressort: Wissenschaft
==============
(8) SZENARIEN, DIE FURCHT EINFLOESSEN: Forscher studieren
frühere Einschläge
Bremer Nachrichten, 9. Januar 2002
http://www.bremer-nachrichten.de/aus_aller_welt/fs_bn_ausallerwelt.html?id=261433
Von unserem Redakteur
Jürgen Wendler
Bremen. Asteroiden beflügeln die Fantasie - umso mehr, weil seit
einiger
Zeit auch das Aussterben der Dinosaurier vor etwa 65 Millionen
Jahren mit
dem Einschlag eines solchen Kleinplaneten in Verbindung gebracht
wird.
Apokalyptische Visionen haben die Menschen schon immer gefesselt,
und das weiß natürlich auch die Filmindustrie: Streifen wie
"Armageddon"
oder "Deep Impact" sind das Ergebnis. Doch es ist
keineswegs nur Panikmache,
was die Profiteure der menschlichen Sensationslust präsentieren.
Wissenschaftler lassen keinen Zweifel daran, dass
Asteroideneinschläge
verheerende Folgen für das Leben auf der Erde haben können. Was
genau dabei
passiert, studieren Forscher an verschiedenen Punkten auf der
Erde.
Besondere Aufmerksamkeit genießt der so genannte
Chicxulub-Krater, der vor
65 Millionen auf der Halbinsel Yucatan in Mexiko entstand. Ein
internationales Forschungsprogramm, an dem auch das
Geoforschungszentrum
Potsdam beteiligt ist, soll unter anderem grundlegende
Erkenntnisse über die
Größe und stoffliche Beschaffenheit des Asteroiden, die Menge
der
freigesetzten Energie und die physikalischen sowie chemischen
Prozesse beim
Einschlag liefern. Dazu müssen mit Hilfe von Bohrungen tief
liegende
Bodenschichten untersucht werden.
Wie das Geoforschungszentrum betonte, hatte der Asteroid einen
Durchmesser
von mehr als zehn Kilometern. Er traf mit einer Geschwindigkeit
von über 25
Kilometern pro Sekunde auf die Erdoberfläche - damals befand
sich an der
Aufschlagstelle eine flaches Meer - und
drang einige Kilometer tief in die Erdkruste ein. "Die
enorme
Einschlagsenergie entsprach mehr als dem Zehntausendfachen des
gesamten
Arsenals an Nuklearwaffen der Welt", erklärte das Potsdamer
Zentrum. Der
Krater, der erst vor einigen Jahren unter einer dicken Schicht
von
Sedimenten aufgespürt werden konnte, hat einen Durchmesser von
etwa 200
Kilometern.
Die Folgen des Einschlags waren gewaltig. Die Wissenschaftler
gehen davon
aus, dass Wasser und Gestein verdampften beziehungsweise
zerfielen.
Wahrscheinlich wurden innerhalb weniger Minuten einige Hundert
Milliarden
Tonnen Kohlendioxid, Schwefeldioxid und Wasserdampf in die
Atmosphäre
geschleudert. Feiner Staub schirmte das Sonnenlicht ab, eine
Flutwelle raste
um die Erde, das Klima wurde instabil. Das alles könnte der
Grund dafür
sein, dass damals, an der Grenze der Kreidezeit zum Tertiär, ein
Artensterben von gigantischem Ausmaß begann. Was schon sehr viel
kleinere
Asteroiden anrichten können, zeigte sich im Juni des Jahres
1908, als ein
etwa 60 Meter großer und 15 Kilometer pro Sekunde schneller
Asteroid in etwa
neun Kilometern Höhe über Sibirien explodierte. Dabei wurde die
Energie von
zehn Megatonnen TNT freigesetzt. Die Schockwelle verwüstete ein
Gebiet von
mehr als 2200 Quadratkilometern, ein Areal also, das mit dem
Großraum Berlin
vergleichbar ist. Weil das damals betroffene Gebiet fast
menschenleer war,
gab es wahrscheinlich kaum Todesopfer. Nach Angaben des Potsdamer
Geoforschungszentrums ist in Berichten von zwei Toten die Rede.
© 2000 nordwest.net
=============
(9) ASTEROID FLIEGT NAHE AN ERDE VORBEI
Frankfurter Allgemeine Zeitung, 7. Januar 2002
http://www.faz.net/IN/INtemplates/faznet/default.asp?tpl=uptoday/content.asp&doc={141F34E1-41F3-4E4D-94B7-BEE5BE1845EE}&rub={32ADA522-4834-4401-88D5-934
A2B06A26B}
7. Jan. 2002 Mit seinen 300 Metern Länge hätte der Asteroid,
der am Montag
nach astronomischen Verhältnissen nahe an der Erde vorbeiflog,
große
Zerstörung anrichten können. Doch 833.000 Kilometer trennten
ihn am nächsten
Punkt seiner Flugbahn von der Erde, das ist doppelt so weit
wie die Entfernung Erde-Mond.
"2001 YB5" tauften die Astronomen den Himmelskörper,
der der größte Asteroid
in Erdnähe seit 1937 war. Und erst am 7. August 2047 wird
"1999 AN10" dem
Planeten ähnlich nahe kommen. Dieser Asteroid wird Berechnungen
zufolge
389.000 Kilometer an uns vorbeifliegen.
Riesiger Krater und Verwüstung
Falls "2001 YB5" die Erde getroffen hätte, mäße sein
Krater zwölf Kilometer.
Die Energie, die der Aufschlag freisetzte, entspräche mehreren
hundert
Atombomben und verwüstete einen Umkreis von 50 bis 100
Kilometern mit
Trümmern und Erdbeben. Falls Kernkraftwerke oder Chemieanlagen
getroffen
würden, sei die Gefahr für die Menschheit ungleich größer,
sagte Christian
Gritzner von der Technischen Universität Dresden. Bei einem
Einschlag ins
Meer könne tatsächlich Flutwellen wie im Film "Deep
Impact" geben.
Erst 1903 traf ein 60 Meter langer Asteroid Sibirien und
verwüstete ganze
Landstriche. Einen Asteroideneinschlag vor 65 Millionen Jahren
auf der
mexikanischen Halbinsel Yucatan machen Astronomen für einen
Klimawechsel und
das Aussterben der Dinosaurier verantwortlich.
Allgemein besteht die Theorie, dass Asteroiden für die
Entstehung des Lebens
auf der Erde extrem wichtig waren, weil sie chemische
Verbindungen aus dem
All mitbrachten, die es auf der Erde nicht gab.
Copyright 2002, FAZ
===========
(10) DAS WAR KNAPP
Der Tagesspiegel, 9. Januar 2002
http://195.170.124.152/archiv/2002/01/08/ak-we-6611633.htmlhttp://195.170.124.152/archiv/2002/01/08/ak-we-6611633.html
Am Montag raste ein Asteroid an der Erde vorbei, der eine Stadt
wie Berlin
hätte auslöschen können
Andreas Oswald
Das hätte schief gehen können. Die meisten Bewohner der Erde
waren
ahnungslos, als am Montag ein Himmelskörper - ein so genannter
Asteroid -
mit einem Durchmesser von 300 Metern an diesem Planeten knapp
vorbeisauste.
Nur 833 000 Kilometer trennten uns von dem gewaltigen Geschoss,
das eine
Geschwindigkeit von mehr als 100 000 Kilometer in der Stunde hat.
Die
Entfernung zwischen der Erde und dem Asteroiden war gemessen an
kosmischen
Relationen denkbar gering. Nur eine winzig veränderte Umlaufbahn
hätte ihn
auf die Erde lenken können. Das ist vergleichbar mit einem
Porsche, der mit
200 km/h bei Rot über die Ampel an einer Gruppe wartender
Fußgänger
vorbeirast. Eine kleine Abweichung, und es gibt eine Katastrophe.
Hätte der Asteroid mit dem Namen "2001 YB5" die Erde
getroffen, er hätte
unermessliche Schäden verursacht. Ein Stadt wie Berlin wäre im
Falle eines
Treffers vollständig zerstört worden, auch das Umland wäre
großflächig
verwüstet. Eine dicke Staubschicht würde in die Atmosphäre
geschleudert, der
Himmel würde sich verdunkeln, das Wetter würde sich verändern
mit großen
Konsequenzen für ein großes Terrain. Die Sonne käme nicht mehr
durch, es
würde eiskalt werden.
Ein langer einschlagsbedingter Winter, wie er einst zum
Aussterben der
Dinosaurier geführt haben soll, wäre aber nicht zu befürchten
gewesen. "Dazu
war er nicht groß genug", sagt Gerhard Hahn,
wissenschaftlicher Mitarbeiter
des Instituts für Weltraumsensorik und Planetenerkundung in
Berlin-Adlershof. Dieses Institut ist das einzige, das in
Deutschland die
Gefahr durch Himmelskörper beobachtet und untersucht. In den USA
gibt es
mehrere Institutionen und auch das dortige Militär hat erkannt,
dass sich
mit dieser Gefahr neue Projekte finanziell legitimieren lassen.
100 Meter große Riesenwellen
"Am größten ist die Wahrscheinlichkeit, dass ein Asteroid
ins Meer fällt.
Dann drohen Riesenwellen, die auf die Küsten zurasen
würden", sagt Hahn. Sie
könnten sich je nach Küstenbeschaffenheit bis zu 100 Meter
auftürmen und
große Verwüstungen verursachen. Bilder wie in dem
Katastrophenstreifen "Deep
Impact" könnten durchaus der Realität entsprechen.
Da wird es langsam Zeit, dass sich Internationale Organisationen
Gedanken
über eine Abwehr machen. Die Nasa ist elektrisiert und hat
umgehend
Informationen über den jüngsten Asteroiden ins Internet
gestellt. Ein
Himmelskörper dieser Größe nähert sich nur sehr selten der
Erde, beruhigt
Donald Yeomans vom Jet Propulsion Laboratory der NASA im
kalifornischen
Pasadena. Aber niemand weiß, ob der Einschlag in 5000 Jahren
stattfindet,
oder schon übermorgen.
Beunruhigend in diesem Zusammenhang ist die Tatsache, dass der
Asteroid vom
Montag erst im Dezember entdeckt worden war. Das heißt, dass es
nicht
genügend Zeit gegeben hätte, gefährdete Gebiete zu warnen.
"Es dauert Tage
und Wochen, nach der Entdeckung die Bahn präzise
vorherzuberechnen", sagt
Hahn.
Von manchen Himmelskörpern weiß man schon heute, dass sie sich
in zehn oder
20 Jahren der Erde nähern werden. Und man weiß, ob eine Gefahr
von ihnen
ausgeht, weil ihre Bahn längst genau berechnet ist. Derzeit gibt
es keinen
einzigen bekannten Himmelskörper, der gefährlich werden kann.
Aber das muss nichts heißen. Das Universum ist groß, jeden Tag
kann ein
neuer entdeckt werden, der wenige Tage darauf mit
Riesengeschwindigkeit die
Erdumlaufbahn passiert. Die wenigen Institutionen, die sich
bislang mit der
Beobachtung von Himmelskörpern beschäftigen, reichen bei weitem
nicht aus,
alle potentiell gefährlichen Himmelskörper zu beobachten.
Da ist es ein Glück, dass es überall auf der Welt Leute gibt,
die aus
privatem Interesse Sterne gucken. Solche Privatastronomen sind es
häufig,
die einen Himmelskörper als erste entdecken und ihn sogar
fotografieren. Das
Internet ist voll von Websites und Foren, in denen sich diese
Freaks
untereinander verständigen.
Mit Atomraketen abschießen
Der jetzige Asteroid "2001 YB5" war unter anderem von
den tschechischen
Sternforschern Jana Ticha und Milos Tichy beobachtet worden.
"Der Asteroid
war sehr sehr nahe", sagte Ticha. Lenka Sroubkova vom
Planetarium in
Oldrichov (Mittelböhmen) sagte, "die hohe Geschwindigkeit
des Asteroids löst
im Observatorium eine automatische Kamera aus - das ist das
gleiche Prinzip,
das ein Polizei-Radar bei Rasern benutzt". Im Jahr 2027
werde der ein
Kilometer große Asteroid "1999 AN10" sogar noch näher
an der Erde
vorbeirasen.
Der nächste bereits bekannte Asteroid von ähnlicher
Größenordnung und
Entfernung zur Erde soll laut NASA am 2. Weihnachtsfeiertag 2011
an der Erde
vorbeirasen. "2000 YA" wird dann von der Erde rund drei
Mal so weit entfernt
sein wie der Mond. Insgesamt beobachtet die NASA derzeit 363
potenziell
gefährliche Asteroiden. Als potenziell gefährlich gelten
Gesteinsbrocken,
die größer als etwa 150 Meter sind und der Erde näher als etwa
7,5 Millionen
Kilometer (etwa 20-fache Mondentfernung) kommen.
Kann das Militär Asteroiden abwehren? Warum schicken die USA
nicht schon
heute ganz viele Atomraketen zu anderen Himmelskörpern, um zu
testen, ob es
funktioniert? Diese Idee gibt es seit längerem. Doch es ist ein
schwieriges
Unterfangen. Nicht nur politisch. Würde eine Atomrakete einen
Asteroiden
treffen und ihn zerstören, dann käme der Himmelskörper als
Schrotladung auf
die Erde, dazu noch in verstrahltem Zustand.
Der atomare Sprengkopf müsste in gehöriger Entfernung
explodieren, um einen
Druckimpuls zu erzeugen, der die Bahn des Asteroiden um einige
Millimeter
ändert, damit er die Erde nicht mehr treffen kann.
Doch davon sind wir weit entfernt, Es gibt bislang lediglich
Projekte wie
die "Eros-Mission", die eine Sonde auf Himmelskörpern
landen lassen, um
weitere Erkenntnisse zu gewinnen. Aber andere Pläne gehen schon
weiter. Die
USA planen eine Mission, bei der ein Himmelskörper beschossen
werden soll.
Das wird aber noch ein paar Jahre dauern, sagt Hahn. Dafür steht
der Name
der Misson schon fest.
Er kommt aus Hollywood: "Deep Impact".
Copyright 2002, Der Tagesspiegel
==============
(11) KOSMISCHE HAARESBREITE: DAS FRUEHWARNSYSTEM HAT VERSAGT
Der Tagesspiegel, 9. Januar 2002
http://195.170.124.152/archiv/2002/01/08/ak-mn-5512766.html
Alexander S. Kekulé
Es geschah am frühen Morgen, kurz nach Sonnenaufgang.
Augenzeugen
beobachteten einen grellen Lichtblitz am Horizont, dann gab es
eine
gewaltige Detonation von der Stärke mehrerer hundert
Hiroshima-Bomben: Ein
riesiger Meteorit war mit über fünffacher Schallgeschwindigkeit
in die
Atmosphäre eingedrungen und in etwa 8,5 Kilometern Höhe
explodiert. Die
Detonation machte 2150 Quadratkilometer Wald - die
zweieinhalbfache Fläche
Berlins - dem Erdboden gleich, die Schockwelle raste zweimal um
den Globus.
Die apokalyptische Szene, die wie ein Ausschnitt aus dem
Hollywood-Schocker
"Deep Impact" anmutet, ist keine Fiktion: Die
gigantische
Meteoriten-Explosion ereignete sich am 30. Juni 1908,
glücklicherweise in der kaum besiedelten Tunguska-Region
Zentralsibiriens.
Vergangenen Montag, am 7. Januar 2002, entging die Menschheit nur
knapp
einer schlimmeren Katastrophe: Um 7 Uhr 57
mitteleuropäischer Zeit verfehlte der Asteroid "2001
YB5" die Erde um nur
830 000 Kilometer, etwa der doppelten Entfernung des Mondes - in
kosmischen
Maßstäben eine winzige Haaresbreite. Bei einem Einschlag auf
dem Festland
hätte der etwa 300 Meter große Gesteinsbrocken einen
Zerstörungsradius von
800 Kilometern hinterlassen - genug, um ein kleineres Land zu
vernichten.
Bei einem Sturz ins Meer hätte die gewaltige Flutwelle immerhin
noch eine
verheerende Wirkung auf küstennahe Regionen gehabt.
Mit seinem Vorbeiflug im Abstand von 0,0056 Astronomischen
Einheiten (AE)
lag der Asteroid weit unterhalb der Warnschwelle für "close
encounters" von
0,2 AE (eine AE ist die mittlere Entfernung zwischen Erde und
Sonne).
Trotzdem blieb die in der Vergangenheit durch Asteroiden auf
Beinahe-Kollisionskurs ausgelöste, weltweite Panikstimmung
diesmal aus. Der
Grund hierfür ist das eigentlich Besorgnis erregende: 2001 YB5
wurde erst am
27. Dezember entdeckt - gegen einen Asteroiden auf Kollisionskurs
wäre bei
einer Vorwarnzeit von knapp 11 Tagen absolut nichts auszurichten
gewesen. Im
Gegensatz dazu wurden die anderen "potenziell gefährlichen
Asteroiden", die
in den letzten Jahren die Weltuntergangs-Stimmung anheizten,
vergleichsweise
frühzeitig entdeckt: Der 1999 gesichtete "1999 AN10"
wird erst im Jahre 2027
haarscharf an der Erde vorbeifliegen, der im vergangenen Jahr
entdeckte
"2000 BF19" wird für diesen Juli erwartet.
Der wichtigste Grund für das Versagen des Frühwarnsystems bei
2001 YB5 ist
seine ungünstige Größe. Nach gegenwärtiger Auffassung würde
ein Meteorit mit
mehr als einem Kilometer Durchmesser eine globale Katastrophe
auslösen - wie
der gewaltige Einschlag in Mexiko, der vor 65
Millionen Jahren zum Aussterben der Dinosaurier führte. Diese
Riesenbrocken,
deren Zahl in Erdnähe kürzlich auf 1200 geschätzt wurde,
lassen sich
vergleichsweise leicht verfolgen. Die Wahrscheinlichkeit, dass
einer von
ihnen in den kommenden 100 Jahren die Erde trifft, ist
aber verschwindend gering.
Im Gegensatz dazu wurde die Gefahr durch mittlere Asteroiden von
einigen
hundert Metern Durchmesser bisher unterschätzt: Sie gehen der
Weltraum-Überwachung NEAT (Near Earth Asteroid Tracking) durch
die Lappen.
Eine vergangenen November veröffentlichte Studie ergab, dass im
zwischen den Bahnen von Mars und Jupiter gelegenen
"Asteroidengürtel" durch
Kollisionen ständig mittelgroße Gesteinstrümmer neu entstehen,
die
unvermittelt in Richtung Erde geschleudert werden können. Ein
Frühwarnsystem
könnte Asteroiden und aus den äußeren Regionen des
Sonnensystems
heranfliegende Kometen rechtzeitig genug erkennen, um sie -
zumindest
theoretisch - durch Abwehrraketen vom Kollisionskurs abzulenken.
Wäre solch
ein Projekt nicht allemal sinnvoller, als ein
"Star-Wars"-Programm gegen
irdische Widersacher?
Der Autor ist Direktor des Instituts für Medizinische
Mikrobiologie an der
Martin-Luther-Universität in Halle-Wittenberg.
2001 © Tagesspiegel Online Dienste Verlag GmbH
==========
(12) DIE ERDE SCHRAMMT KNAPP AM CRASH VORBEI
Die Tageszeitung, 9. Januar 2002
http://www.taz.de/pt/2002/01/09/a0077.nf/text
Gegnerischer Brocken war 300 Meter dick und könnte ein kleines
Land
auslöschen. Briten gründen Zentrum, um künftig
Einschlagsgefahr zu bannen
BERLIN taz Ziemlich knapp raste diese Woche ein Asteroid an
der Erde
vorbei: Ein Steinbrocken von rund 300 Meter Durchmesser passierte
uns am
Montag in einem Abstand von - astronomisch gesehen - winzigen
830.000
Kilometern Distanz. Das entspricht rund dem doppelten Abstand zum
Mond. Das
Objekt wurde erst im Dezember entdeckt und trägt den Namen
"2001
YB5".
Der Asteroid, auch Planetoid genannt, bewegte sich mit 100.000
Stundenkilometern und löste durch sein Tempo in diversen
Sternwarten der
Welt automatische Kameras aus - ähnlich wie bei einer
Radarkontrolle auf der
Autobahn. Würde ein Steinbrocken dieser Größe auf die Erde
stürzen,
schlüge er zwar nur einen Krater von etwa sechs Kilometern
Durchmesser, doch
Druckwelle und Erschütterungen würden schwere Verwüstungen
anrichten. Seine
Sprengkraft entspricht der von rund 50.000 Hiroschima-Bomben.
Träfe er ins
Meer, entstünden gewaltige Wellen, die ganze Küstenstädte
überfluten
könnten. Dass so ein Geschoss die Erde trifft, kommt nach
Schätzungen von
Astronomen vielleicht alle 100.000 Jahre vor.
Ab 2.000 Meter Dicke hat ein Asteroid das Potenzial, das globale
Klima stark
zu beeinträchtigen, die Ozonschicht zu zerstören und ein Land
so groß wie
Deutschland zu vernichten. Ab rund 10.000 Meter Durchmesser muss
man mit der
Zerstörung des getroffenen Kontinents und weltweitem
Artensterben rechnen.
"2001 YB5" kam genau pünktlich, um den jüngsten
Beschluss der britischen
Regierung zu unterstreichen. Deren Wissenschaftsminister, Lord
Sainsbury,
verkündete zum Jahresbeginn, bis Ostern ein Beobachtungszentrum
am
Nationalen Raumfahrtzentrum in Leicester einrichten zu wollen:
das Near
Earth Objekts Centre (NEO Centre; NEO = Objekte nahe der Erde).
Damit will
man dort nun die Gefahr von Asteroideneinschlägen ähnlich ernst
nehmen wie
in den USA, für die die
Nasa ein entsprechendes Programm unterhält. Die offizielle
britische
NEO-Expertenkommission regt darüber hinaus an, "gemeinsam
mit anderen
Regierung Studien in Auftrag zu geben, die mögliche Wege
analysieren, wie
die Schäden eines Einschlages vermindert und eintreffenden
Objekts abgelenkt
werden können". In diesem Jahr wird auch das
Wissenschaftsforum der OECD
über ein mögliches Vorgehen beraten.
Der letzte größere Einschlag fand 1908 in Sibirien statt, wo
ein 60 Meter
dicker Stein beim Eintritt in die Atmosphäre so sehr erhitzt
wurde, dass er
acht Kilometer über dem Boden explodierte: 2.000 Quadratkilomer
Wald wurde
umgelegt, viele Brände entstanden.
Der berühmteste Einschlag fand vor 65 Millionen Jahren in Mexiko
statt,
schlug einen 180 Kilometer großen Krater und ließ
möglicherweise die
Dinosaurier aussterben. Inzwischen wird auch spekuliert, ob nicht
am Anfang
der Saurierherrschaft ein Einschlag stand, der ihre Konkurrenten
vernichtete.
Das müsste dann so um die 230 Millionen Jahre her sein. Ein
passender Krater
wird noch gesucht. MATTHIAS URBACH
© Contrapress media GmbH
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