PLEASE NOTE:
*
CCNet DIGEST, 21 August 1998
----------------------------
(1) INTERSTELLAR METEOROIDS
Duncan Steel <dis@a011.aone.net.au>
(2) METEORITE DUST TO BE TESTED
The Electronic Telegraph
(3) GREENLAND IMPACTOR MAY HAVE COME FROM INTERSTELLAR SPACE
MSNBC Space News
http://www.msnbc.com/news/189444.asp
(4) DOUBTS ABOUT INTERSTELLAR ORIGIN OF GREENLAND METEORITE
Mike DiMuzio <mdimuzio@cisnet.com>
(5) TASK COMPLETED IN GREENLAND
The Tycho Brahe Expedition
http://www.astro.ku.dk/tycho/tbe98/english/status/
(6) DYNAMICAL EVOLUTION OF COMETARY ASTEROIDS
N.W. Harris & M.E. Bailey, ARMAGH
OBSERVATORY
(7) CCNet FORMAT
Joy Warren <thewarrens@wga.org>
(8) NEW FINDINGS COULD HELP FUTURE COLONISATION OF THE MOON
Andrew Yee <ayee@nova.astro.utoronto.ca>
(9) YAWN, YAWN: ANOTHER END OF THE 'WEEKLY WORLD NEWS' HOAX
Jeremy Tatum <UNIVERSE@UVVM.UVic.CA>
===============
(1) INTERSTELLAR METEOROIDS
From Duncan Steel <dis@a011.aone.net.au>
Dear Benny,
Item from The Daily Telegraph (21 August 1998) appended.
The existence of meteoroids and/or comets arriving from
interstellar
space is a subject which has been contentious for decades; see:
A.D. Taylor, W.J. Baggaley & D.I. Steel, Discovery of
interstellar dust
entering the Earth's atmosphere, Nature, 380, 323-325 (1996).
Duncan Steel
-------
(2) METEORITE DUST TO BE TESTED
From the Electronic Telegraph
International News
Friday 21 August
1998
Issue 1183
Meteorite dust to be tested
DUSTY remains of a meteorite that crashed into Greenland are to
be
tested to see if it came from outside our solar system.
The extreme speed of the object, recorded on video film, suggests
it
may have come from interstellar space, which would mark a first
if
confirmed. A giant fireball was seen on 9 December over a large
part of
southern Greenland. Some reports said that "night was turned
into day"
and others likened it to "a giant millipede of fire with
yellow,
glowing legs".
The meteorite was calculated to weigh at least a ton. An
expedition to
the south-western part of the Greenland ice cap found no large
meteorite fragments, only about 200 samples of dust.
END
Copyright 1998, The Daily Telegraph
=======================
(3) GREENLAND IMPACTOR MAY HAVE COME FROM INTERSTELLAR SPACE
From MSNBC Space News
http://www.msnbc.com/news/189444.asp
Sleuths bring meteorite dust from Greenland: Space rock may have
come
from beyond solar system
REUTERS
COPENHAGEN, Denmark, Aug. 20 A meteorite which crashed
into Greenland
last December may have come from outside our solar system, a
Danish
astronomer said Thursday. He said that would be a world
first in the
meteorite field.
A FOUR-WEEK EXPEDITION to the southwestern part of the Greenland
ice
cap failed to find fragments of the meteorite but returned home
Wednesday with about 200 samples of dust.
Astronomer Lars Lindberg Christensen of Denmarks Tycho
Brahe
Planetarium, a member of the seven-man expedition, said analysis
of the
dust samples could yield clues to the origin of the meteorite.
It may have come with enough speed that it actually
originated outside
our solar system. That would make it a world first, he told
Reuters by
telephone.
The center has collected more than 100 eyewitness reports, three
seconds of videotape and data from a U.S. defense satellite of
the
meteorites plunge through the Earths atmosphere.
Calculations based on the video frames of the meteorites
descent,
which lit up the night sky over Greenland on Dec. 9, put its
velocity
at 35 miles per second, or one and a half times the maximum speed
of
any known meteorite in our solar system, Christensen said.
At such a speed, the object would have disintegrated, and the
only
traces would be dust, he said.
It also means that it is most likely that the snow samples
contain
dust from the meteorite, he said.
The expedition collected enough dust to allow the particles to be
examined thoroughly, revealing their molecular and atomic
composition.
If analysis shows the dust particles are more than 4.5 billion
years
old, that would confirm that the meteorite originated in
interstellar
space, he said. Our solar system is thought to have formed 4.5
billion
years ago.
Preliminary findings from the Niels Bohr astrophysics and
geophysics
institute and the geological institute of the University of
Copenhagen
could be ready in a matter of months, Christensen said.
Traces of more than 10,000 meteorites have been found on Earth,
but the
Greenland find is special because it is one of the few that have
been
seen plunging from space.
© 1998 Reuters Limited. All rights reserved.
====================
(4) DOUBTS ABOUT INTERSTELLAR ORIGIN OF GREENLAND METEORITE
From Mike DiMuzio <mdimuzio@cisnet.com>
Reuters is reporting that the Danish Greenland Meteorite
expedition
has ended without their finding any fragments from the fall last
December.
However, they returned with over 200 dust samples. The scientists
estimate that the meteoroid hit Earth's atmosphere at over 35
miles per
second, 50 percent fster that the speed of any known
meteorite. This
led them to speculate that the meteorite originated outside our
solar
system.
I find this pretty thin evidence, as I believe several meteor
showers
have meteor speeds estimated well in excess of 35 miles per
second, but
I could be wrong. They plan on analyzing the age of the
dust particles
to see if they are older than the solar system. Because of
its speed,
they speculate the meteorite disintegrated upon entry and any
large
pieces may never be found.
Of course, this is only speculation on their part, since they
have yet
to positively identify the dust as meteoritic in origin. A ststus
page
can be found
at http://www.astro.ku.dk/tycho/tbe98/english/status/
Mike
=====================
(5) TASK COMPLETED IN GREENLAND
From The Tycho Brahe Expedition
http://www.astro.ku.dk/tycho/tbe98/english/status/
(August 17)
The participants of the expedition have completed their task as
well as
could be expected under the given circumstances. The line of
directions
from the steering committee were followed, and in spite of the
week
wasted (which is normal in Greenland, because of the changing
weather),
they still managed to cover a larger search area than originally
planned. A week before the end of the expedition new information
was
received from the Czech meteorite expert Ceplecha and some
American
experts that the fall-out zone might be some km more to the
north.
These informations were e-mailed directly to the camp and plans
were
made to cover the new northern search area.
The steering committee is satisfied with the fact, that the
expedition
managed to collect large amount of snow samples for further
studies of
possible dust from the meteorite. The team even had time to
search
large areas inside the search area for fragments - unfortunately
with
no luck. The studies of the snow in the search area were most
important
this summer, before the snow melts or is covered by new snow.
The dust samples now have to go through a long and thorough test
to
determine if the samples contain authentic meteoric material or
not.
This week a team will be appointed to reach a decision hopefully
within
a few months.
==================
(6) DYNAMICAL EVOLUTION OF COMETARY ASTEROIDS
N.W. Harris & M.E. Bailey: Dynamical evolution of cometary
asteroids
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1998, Vol.297,
No.4,
pp.1227-1236
*) ARMAGH OBSERVATORY, COLLEGE HILL, ARMAGH BT61 9DG, NORTHERN
IRELAND
We present results from long-term numerical integrations of
hypothetical Jupiter-family comets (JFCs) over time-scales in
excess of
the estimated cometary active lifetime. During inactive periods
these
bodies could be considered as 'cometary' near-Earth objects
(NEOs) or
'cometary asteroids'. The contribution of cometary asteroids to
the NEO
population has important implications not only for understanding
the
origin of inner Solar system bodies but also for a correct
assessment
of the impact hazard presented to the Earth by small bodies
throughout
the Solar system. We investigate the transfer probabilities on to
'decoupled' subJovian orbits by both gravitational and
non-gravitational mechanisms, and estimate the overall inactive
cometary contribution to the NEO population. Considering
gravitational
mechanisms alone, more than 90 per cent of decoupled NEOs are
likely to
have their origin in the main asteroid belt. When
non-gravitational
forces are included, in a simple model, the rate of production of
decoupled NEOs from JFC orbits becomes comparable to the
estimated
injection rate of fragments from the main belt. The
Jupiter-family
(non-decoupled) cometary asteroid population is estimated to be
of the
order of a few hundred to a few thousand bodies, depending on the
assumed cometary active lifetime and the adopted source region.
Copyright 1998, Institute for Scientific Information Inc.
================
(7) CCNet FORMAT
From Joy Warren <thewarrens@wga.org>
Dear Benny,
The controversy over your CCNet format prompts me to send you
this note.
Though I am a writer, not a scientist, I applaud your efforts and
appreciate the time and work you put in to make this forum a
"happening". Once upon a time Copernicus forced us to
reassess our
place in the universe. Now, as you said, we are on the frontier
of a
new world view based upon new discoveries that both inform and
remind
us of our precarious existence. I join you in your dream - or
dare I
say prayer - that this new understanding will lead us to a unity
of
vision which will transform the world and maybe even save us from
the
fate of the dinosaurs.
Thank you for your vision and for your work.
Joy Warren
====================
(8) NEW FINDINGS COULD HELP FUTURE COLONISATION OF THE MOON
From Andrew Yee <ayee@nova.astro.utoronto.ca>
University of New Hampshire
Contact:
Toni Galvin can be contacted at 603-862-3511 or at 603-431-0492.
August 20, 1998
UNH Researcher Examines Moon's Atmosphere
Findings could help future colonization of the lunar surface
By Carmelle Druchniak, UNH News Bureau
DURHAM, N.H. -- A University of New Hampshire space scientist
examining
the atmosphere of the Moon says new findings might prove useful
in
future colonization of the lunar surface.
Antoinette Galvin, UNH research associate professor in the
Institute
for the Study of Earth, Oceans and Space, is co-author of a
research
paper detailing the discovery of small amounts of oxygen, silicon
and
aluminum in the moon's atmosphere. The findings are based on
observations by the Suprathermal Ion Composition Spectrometer
(STICS)
aboard the WIND spacecraft and appear in the American Geophysical
Union's publication "Geophysical Research Letters."
Galvin, who recently joined the UNH faculty from the University
of
Maryland, is the lead co-investigator of the STICS sensor.
She explains that the moon does not have an atmosphere like
Earth. "If
you look in almost any textbook listing planetary atmospheres,
the moon
will be listed as having 'none' or 'essentially none,'" she
points out.
The low lunar gravity (one-sixth that of Earth) means that the
moon has
a smaller "escape velocity" -- 1.5 miles per second
compared to the
Earth's 7 miles per second -- "so almost any atmosphere the
moon gets,
it immediately drifts off or escapes into space. That means the
atmosphere must be continuously replenished."
The lunar atmosphere is also only 1/100,000,000,000,000 that of
Earth,
and in fact is often called the exosphere. For planets, the
exosphere
is the tenuous part of the atmosphere beyond the ionosphere that
blends
into space, says Galvin. "The Earth's exosphere starts at
480
kilometers up. For the moon, you have the surface of the moon and
--
bang! -- the exosphere right next to it."
The lunar atmosphere was first found by the Apollo 17 crew, which
detected helium and argon. Ground-based observations later found
sodium
and potassium, but the question remained: since these elements
made up
less than 10 percent of the moon's atmospheric density, what
other
elements were there?
In answer to that question, STICS detected what are called
"lunar
pick-up ions." Galvin explains that when atoms are struck by
ultraviolet radiation from the Sun, they absorb the energy and
kick out
an electron, becoming ions. "Ions are subject to the solar
wind
electric and magnetic fields -- we call it being 'picked up' by
the
solar wind," says Galvin. The pick-up ions can receive quite
a boost in
speed this way and accelerate up to twice the
400-kilometer-per-second
solar wind speed.
It was through its detection of pick-up ions that STICS
discovered
oxygen, silicon and aluminum.
"But where does this atmosphere come from?" asks
Galvin. "The
composition gives us a clue."
The helium probably comes from the solar wind hitting the moon,
she
explains. "In this way, some of the solar wind becomes part
of the
lunar atmosphere. But the other elements observed, both on the
ground
and by STICS, are either from objects impacting the moon and
vaporizing, or from the moon itself." Some may be due to
out-gassing
from the lunar interior. As for the aluminum and silicon seen by
STICS,
the origin is most like sputtering: the solar wind hits the lunar
surface, and knocks out atoms from that surface.
The STICS paper does not speculate as to the original source of
the
lunar oxygen. It may come from the disassociated molecules that
contain
oxygen, such as water, or like the aluminum and silicon may come
from
sputtering off the surface. Galvin points out that NASA's Lunar
Prospector recently confirmed the presence of ice on the moon,
and some
theorize that the ice seen at the lunar poles may be accumulated
from
this thin atmosphere.
Scientists now believe that water molecules -- whether out-gassed
or
left from comet impacts -- migrate to colder regions, where they
condense as ice back into the ground. They suggest this is the
most
likely way that ice may have collected in the polar shadows.
"So if the moon was really airless, there would be no
collected H2O as
ice," says Galvin. "This ice may be used by future
colonists."
She adds, "The surface itself may be a colony's source for
metals, such
as the aluminum seen by STICS, so these aspects also could be
important
for colonization of the moon."
Lunar exploration also can help us learn more about other
heavenly
bodies, says Galvin.
"The moon is not the only 'airless' body that in fact has a
thin
atmosphere. Some planets, asteroids and other moons have similar
atmospheres. Any flyby or orbit of these objects by other
spacecraft
should look for pick-up ions. Then one will get an idea of the
origin
of the atmosphere and even some information on the composition of
the
surface."
=====================
(9) YAWN, YAWN: ANOTHER END OF THE 'WEEKLY WORLD NEWS' HOAX
From Jeremy Tatum <UNIVERSE@UVVM.UVic.CA>
From Weekly World News, August 25, obtained at my friendly
grocery
check-out counter.
----------
ARMAGEDDON COMET SPEEDING TOWARDS EARTH - & COULD STRIKE IN
OCTOBER!
NASA is hush-hush - but sources say they're scared to death!
NASA ON TOP SECRET RED ALERT!
DOOMSDAY COMET SPEEDING TOWARDS EARTH!
ESTIMATED COLLISION DATE: OCT. 29, 1998!
Experts are warning Clinton: 3 billion people will die!
Paris - A massive comet as big as Europe is speeding toward Earth
and
unless we can find some way to stop it, 3 billion people will die
when
the giant space rock hits - possibly as early as October!
That's the word from a team of frantic scientists who've secretly
met
with leaders of the world's major powers at least six times since
America's Hubble Space Telescope first photographed the runaway
comet
in April.
In their emotion-charged and often grim meetings here, scientists
have
urged leaders of the United States, Russia, England, France,
Germany,
Japan and China to fund the use of nuclear weapons to attempt to
vaporize the comet while it is safely out in space - though most
experts concede that this plan has little, if any, chance of
success.
"The chilling fact is, most scientists now agree that any
attempt to
shoot a comet or an asteroid out of the sky, or even to alter its
course, with nuclear weapons is a virtual impossibility.,"
insisted
famed astronomer Dr Robert Clemson, one of nine scientists who've
been
busy spurring the world's political leaders to action.
"But it's also
a fact that at this point, the use of nuclear weapons is the only
plan
anyone has come up with that has any chance at all of ending this
threat to life as we know it."
Dr Clemson said President Clinton, who has slipped out of
Washington
to attend at least three of the Paris conferences, is so
concerned about
the impending disaster that he has authorized the expenditure of
the
more than $4 billion that NASA and the Pentagon say they'll need
to
modify land-based missiles for an assault on the killer comet.
"Mr Clinton is gravely concerned, as are all the leaders who
met in
Paris," the scientist said. "We may have our
political and ideological
differences among nations here on Earth, but now that the human
race is
threatened with extinction, the world's leaders seem willing to
set
aside these differences in an attempt to save the lives of every
man,
woman and child on the planet. The trouble is, right now we
simply
don't have a clue what to do next."
But experts say unless we find some way to stop it, there is a 93
per
cent chance that the gigantic chunk of ice, rock and space debris
will
slam into Earth at a mind-boggling 141,000 m.p.h. on or around
October
29.
"At that point, one of two things could happen," Dr
Clemson said. "In
the first scenario, the impact would smash Earth to bits, sending
fragments hurtling into space and killing us all. Or it's
possible
Earth would remain intact. But in that case, the collision
would no
doubt kick millions of tons of dirt and debris into the
atmosphere,
veiling the Sun and plunging us into a temporary but devastating
deep-freeze - much like the one believed to have wiped out the
dinosaurs after a comet collided with Earth 65 million years ago.
It's likely that to us as human beings, it won't much matter
which
scenario takes place, however - because it's very likely that
either
way, the human race will cease to exist."
It was Dr Clemson, a world-renowned astronomer with close ties to
NASA,
who first discovered the so-called Clemson Comet while examining
Hubble
photographs last spring. After identifying a tiny point of
light
appearing on one the photos as a comet, the scientist began to
monitor
its speed and trajectory with an earthbound telescope and
determined
that it was on a collision course with Earth. Dr Clemson
immediately
alerted NASA and fellow astronomers around the world, who
persuaded
world leaders to gather for the series of "red-alert"
meetings that
began here in May.. "We're really struggling because
no one knows what
we can do to ward off the comet," Dr Clemson said.
"But we will do
something, that's for certain, because we must do
something."
----------------------------------------
THE CAMBRIDGE-CONFERENCE NETWORK (CCNet)
----------------------------------------
The CCNet is a scholarly electronic network. To subscribe, please
contact the moderator Benny J Peiser at <b.j.peiser@livjm.ac.uk>.
Information circulated on this network is for scholarly and
educational
use only. The attached information may not be copied or
reproduced for
any other purposes without prior permission of the copyright
holders.
The electronic archive of the CCNet can be found at
http://abob.libs.uga.edu/bobk/cccmenu.html