PLEASE NOTE:
*
Date sent: Tue, 03 Mar 1998 14:49:33 -0500 (EST)
From: Benny J Peiser B.J.PEISER@livjm.ac.uk
Subject: CC DIGEST, 03/03/98
To: cambridge-conference@livjm.ac.uk
Priority: NORMAL
CAMBRIDGE-CONFERENCE DIGEST, 3 February 1998
--------------------------------------------
(1) ABSTRACTS OF 29th LUNAR & PLANETARY SCIENCE CONFERENCE
AVAILABLE
Peter Abrahams telscope@europa.com
(2) VISUAL OBSERVATIONS OF METEOR STORMS
Sirko Molau molau@informatik.rwth-aachen.de
(3) MUIRHEAD TO LEAD DEEP SPACE 4/CHAMPOLLION MISSION
Ron Baalke BAALKE@kelvin.jpl.nasa.gov
(4) WHY GOD NEVER GOT TENURE
Benny J Peiser b.j.peiser@livjm.ac.uk
==================================
(1) ABSTRACTS OF 29th LUNAR & PLANETARY SCIENCE CONFERENCE
AVAILABLE
From: Peter Abrahams telscope@europa.com
Subject: Papers on Impact at LPSC
See http://cass.jsc.nasa.gov/meetings/LPSC98/pdf/sess42.pdf
for abstracts of papers to be presented at the 29th Lunar &
Planetary
Science Conference, March 1998 (Adobe Acrobat required)
Some of the more interesting papers on impact phenomena include:
Impacts of meteroids on the moon produce a light flash that was
modeled
to estimate duration, spectra, and shape; for objects of
different
velocities, sizes, and compositions. Impacts release vapor, and
if that
vapor condenses, the temperature of the impact plume remains
constant
for an extended time as evaporation produces a release of energy.
If
there is no condensation, adiabatic cooling causes rapid
temperature
drop. The vapor will be opaque or transparent, depending on the
composition of the soil and the meteoroid. IR detectors would be
much
better than visual light detectors, because often only 10-20% of
the
radiation is at visible frequencies. (Nemtchinov)
Two very intriguing papers concern lunar chondrules, crystalline
spherules under 1 mm in diameter, found in samples returned by 4
lunar
missions. These chondrules have various textures &
mineralogies,
including relict grains and sulfide rims. Most seem to have
crystallized from a melted state while in in free flight. There
is
evidence that these might have been formed as impact melt. These
lunar
chondrules have compositional similarities to lunar highland
samples.
There is no evidence for a meteoritic origin, since they differ
in
mineralogy and composition. Their crystalline qualities seem to
be
related more to cooling rates than composition. An important
conclusion is the possibility that some chondrules in meteorites
formed
from impact events. (Ruzika)
Impact craters on the moon give us a view into the layers of
basalts
that underlie the mare. The Clementine mission provided images at
11
wavelengths. Four craters, 18 to 28 km. in diameter and over 2
km.
deep, were mapped, charting iron content as an indicator of mare
thickness. The crater ejecta was also measured. Evidence was
gained
concerning the thermal and resurfacing history of the moon.
(Thomson)
Verification of the comprehensive test ban treaty (forbidding
underground nuclear bomb tests) includes seismic detectors that
could
be triggered by a meteorite impact. 50 of these detectors, across
the
globe, can detect seismic magnitudes of 3 or 4. This has already
been
an issue of concern; in 1993, a seismic event of mag 3.6 in W.
Australia occurred just north of "where members of the Aum
Shinrikyo
terrorist cult had been trying to mine uranium, and carrying out
tests
with chemical weapons." The conclusion was that the seismic
event was
probably an iron meteorite, creating a crater over 100 meters in
diameter [no mention of discovery of such a crater]. Ablation
&
deceleration in the atmosphere, frequency of iron & stony
meteorites,
water surface of the earth, and other factors were considered.
It is concluded that meteorite impacts that could trigger the
seismic
detectors occur on a time scale of decades. The existing seismic
records probably include meteorite impacts misidentified as
earthquakes. (Chyba)
165 impact craters on Mars were studied from Mariner and Viking
photographs. ‘Unique styles of ejecta’ were noted,
volume of cavity
estimated, later erosion measured, The shapes of the craters were
mathematically analyzed. They are conical and paraboloidal, and
as
diameter increases, they become more spherical. (Garvin)
Unrelated to impact but worthy of mention are some predictions on
Martian caves. Whether formed from underground water flow or
tectonic
activity, caves on Mars might be a likely place to look for
biological
activity. The types of caves that might exist, and the varieties
of
sediment they might contain, are discussed. There are dozens of
papers
on Mars, and there appears to have developed a terminology for
geological eras on Mars; as this article mentions the "Late
Amazonian".
(Grin)
================================
(2) VISUAL OBSERVATIONS OF METEOR STORMS
From: Sirko Molau molau@informatik.rwth-aachen.de
Even though it is still the basic meteor observation technique,
visual
observation has a number of disadvantages and limitations. One of
the
limitations became obvious during the spectacular Leonid meteor
storm
of 1966. When the number of meteors exceeded several shooting
stars per
second, human observers were not able anymore to follow the
activity
with the standard observing techniques.
In 1966, the observers switched to a different method near the
time of
maximum of the Leonid storm. They did not count the individual
meteors
anymore, but opened their eyes for only a second and tried to
estimate
the numbers of meteors at this moment. Until now it is not
perfectly
clear, in how far this change of technique influenced the rates
derived
from the observations afterwards (EZHR>100.000). A recent
A&A paper of
Peter Jenniskens suggested, for example, that the activity may
have
been overestimated by an order of magnitude. There was an
argument in
recent WGN issues, whether human observers are able to give
precise
activity estimates at all, when the equivalent ZHR becomes bigger
than
10.000.
So, one of the main scientific goal for the possible return of
the
storm in 1998 is to calibrate the old observations with new data.
The
idea is to use the same observing techniques as in 1966, but
operate
video systems in parallel to have the 'ground truth'. If the
rates will
be high enough we may find out, whether visual estimates under
these
conditions are systematically in error, and if they are reliable
at
all.
In Germany, a group of about 15 observers is preparing for an
expedition to Mongolia. In one of the preparation meetings the
idea was
born, to write a computer simulation of a meteor storm. This may
give
us a first clue, what to expect and how the chances for accurate
visual
observations are. In addition, different visual methods may be
tested
in advance to find out, which observing technique is most
appropriate
for observations under very high activity.
We started with a simple program of H. Luethen. It displayed an
arbitrary number of lines for just one second, similar to the
1966
observing technique. Later the estimates were compared with the
true
number of lines displayed. The tests have been repeatedly carried
out
by different German observers in the last few weeks. The results
were
promising - usually the relative error was not larger than about
25%. A
detailed analysis will be published in WGN later on.
The major drawback of this first simulation was, that it had only
little in common with reality. It was a good test, whether humans
are
able to estimate a larger number of objects at one instance, but
under
clear skies the job is much more difficult.
This is why I decided to develop an improved simulation. Now,
meteors
are not anymore simple lines, but elongated moving objects. They
do
have different brightnesses, light curves, velocities,
directions,
persistent trains, etc. as in reality. Furthermore, the sequence
of
shooting stars is computed with an exponential distribution.
Thus, the
often reported 'cluster effects' become clearly visible. A number
of
background stars helps to improve the display.
To run the program, a fast PC / graphics card is necessary. The
simulation should be executed under DOS.
The software is available via anonymous from IMO’s ftp
server at
ftp.imo.net, directory /pub/software/metsim, or via our WWW
homepage at
http://www.imo..net/visual/major03.html.
Please, send your questions, data files, suggestions for
improvements,
and other comments to the author
(molau@informatik.rwth-aachen.de).
Enjoy the simulation!
Sirko Molau
----------------------------------------
Sirko Molau -- Video Commission Director
International Meteor Organization
e-mail: video@imo.net
WWW : http://www.imo.net/video
----------------------------------------
==========================
(3) MUIRHEAD TO LEAD DEEP SPACE 4/CHAMPOLLION MISSION
From: Ron Baalke BAALKE@kelvin.jpl.nasa.gov
MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov
Contact: Franklin O'Donnell
FOR IMMEDIATE RELEASE February 26, 1998
MUIRHEAD TO LEAD DEEP SPACE 4/CHAMPOLLION MISSION
Brian K. Muirhead, project manager for NASA's Mars Pathfinder
mission
that delivered a lander and rover to the surface of Mars, has
been named
project manager for the Deep Space 4/Champollion mission to a
comet.
Planned for launch in 2003, the Deep Space 4/Champollion
spacecraft
will rendezvous with Comet Tempel 1 in 2005 and spend several
months
orbiting the comet nucleus making high-resolution maps of its
surface.
The spacecraft will deploy a lander with a 1-meter-long
(3.3-foot)
drill to collect samples that will be analyzed on-site; an
attempt will
be made to return a sample to Earth in 2010.
The project is part of the Deep Space mission series under the
NASA/JPL
New Millennium Program, designed to perform flight demonstrations
of
new spacecraft technologies for solar system and Earth-orbiting
missions.
A native of Chicago, Muirhead joined JPL in 1978 and has worked
on
missions including Galileo to Jupiter and the Earth-orbiting
Spaceborne
Imaging Radar (SIR-C). Muirhead also managed JPL's Advanced
Spacecraft
Development Group and Mechanical Systems Integration Section. He
joined the Mars Pathfinder mission as flight system manager and
was
responsible for the design, development, test and launch of the
spacecraft. After launch, he served as deputy project manager
before
being named project manager upon Pathfinder's successful landing
in
July 1997.
Muirhead holds a bachelor's degree in mechanical engineering from
the
University of New Mexico and a master's degree in aeronautical
engineering from the California Institute of Technology.
JPL is managed for NASA by Caltech.
=======================
(4) WHY GOD NEVER GOT TENURE
From: Benny J Peiser b.j.peiser@livjm.ac.uk
1. Only one major publication...
2. ...in Hebrew
3. No references.
4. It wasn't published in a refereed journal.
5. There are some doubts that he wrote it himself.
6. May be true he created the world, but what has he done since
then?
7. Scientific community has had a hard time replicating his
results.
8. Never applied to the ethics board for permission to use human
subjects.
9. When experiment went awry, tried to cover it by drowning
subjects.
10. When subjects didn't behave as predicted, deleted them from
sample.
11. Rarely came to class and just told students to read the book.
12. Expelled first two students for learning too much.
13. Only had ten requirements, but most of his students failed
them.
--------------------------------
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