PLEASE NOTE:


*
Date sent:        Wed, 22 Oct 1997 09:39:55 -0400 (EDT)
From:             Benny J Peiser <B.J.PEISER@livjm.ac.uk
Subject:          CAMBRIDGE-CONFERENCE DIGEST
To:               cambridge-conference@livjm.ac.uk
Priority:         NORMAL

CAMBRIDGE-CONFERENCE DIGEST, 22 October 1997

1) SCIENTISTS DISCOVER POSSIBLE IMPACT CRATER IN YEMEN

2) MISSIONS TO GATHER SOLAR WIND SAMPLES AND TOUR THREE COMETS
   SELECTED AS NEXT DISCOVERY PROGRAM FLIGHTS

3) SEND YOUR NAME TO A COMET ON A STARDUST SPACECRAFT
 

In view of the constantly increasing information, research and
the growing number of news stories about neo-catastrophism, mass
extinctions, NEOs and related topics, I intend to reduce the number
of separate postings on the CC-network. In order to reduce the
overall number of electronic mail send out on the CC-network, I will
try to compile a regular digest with a list of interesting
information. This digest, I hope, will further help to stem the flood
of electronic information from which we are all suffering, one way or
another.

Benny J Peiser
========================================================================

1) SCIENTISTS DISCOVER POSSIBLE IMPACT CRATER IN YEMEN

from: Ron Baalke <BAALKE@kelvin.jpl.nasa.gov

PUBLIC INFORMATION 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: Mary A. Hardin

FOR IMMEDIATE RELEASE
OCTOBER 20, 1997

SCIENTISTS DISCOVER POSSIBLE IMPACT CRATER IN YEMEN

    Scientists using a variety of spaceborne remote-sensing images,
combined with limited ground research, have discovered what they think is a
possible impact crater in a dry river bed in the Yemen Arab Republic.

    "On the remote-sensing images, the proposed crater appears as a
770-meter-diameter (2,525-foot) circular feature centered on a small wadi or
dry river channel. Although sharp on the remote- sensing images, the feature
is unremarkable in the field," said Dr. Ronald Blom, a research geologist at
NASA's Jet Propulsion Laboratory. "This is another example of how
remote-sensing tools help us see things we wouldn't normally be able to
detect, or might overlook, on the ground."

    Blom and his colleague Dr. Robert Crippen, also of JPL, are
presenting their findings this week at the annual meeting of the Geological
Society of America, being held in Salt Lake City. The image is available at
http://www.jpl.nasa.gov/news .

    They used radar images from the Spaceborne Imaging Radar C/X-Band
Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the space shuttle
in 1994, and enhanced visible and near- infrared images from the Landsat
Thematic Mapper satellite.

    "A very brief field reconnaissance in January 1997 indicates, but
does not confirm, that the feature may well be an impact crater," Blom
explained. "The crater is in a wadi that is filled with sediment and
windblown sand. No direct evidence of an impact, such as overturned rims,
shatter cones, or meteoritic material, were observed. However, large
circular features are uncommon. Other potential explanations for this
circular feature include a sinkhole or volcanic crater. But there was no
field evidence of volcanic or sinkhole activity. Thus, neither seems likely
in this case."

    SIR-C/X-SAR, a joint mission with NASA and the German and Italian
space agencies, is managed by JPL, a division of the California Institute of
Technology, for NASA's Office of Mission to Planet Earth, Washington, DC.
Blom's field work was sponsored by New Wave International and the Kaplan
Fund.

======================================================================= 2)
MISSIONS TO GATHER SOLAR WIND SAMPLES AND TOUR THREE COMETS
   SELECTED AS NEXT DISCOVERY PROGRAM FLIGHTS
 

from: David Morrison <dmorrison@mail.arc.nasa.gov

NEO News (10/21/97)

Dear friends and students of NEOs:

NASA has announced the selection of another NEO mission, to provide
multiple comet flybys.  The Discovery mission called Contour is led
by PI Joseph Veverka of Cornell University.  This is the third NASA
Discovery mission to study small bodies.  Currently the first
Discovery mission, Near Earth Asteroid Rendezvous (NEAR), is en route
to Eros, while under development is the mission Stardust to return
samples of the coma of comet Wild-2.  More details of this Discovery
selection are given in the NASA press release below, taken from the
NASA homepage at http://www.nasa.gov.

David Morrison

------------------------------------------------------
Headquarters, Washington, DC                  October 20, 1997
(Phone:  202/358-1753)

RELEASE:  97-240

MISSIONS TO GATHER SOLAR WIND SAMPLES AND TOUR THREE COMETS
SELECTED AS NEXT DISCOVERY PROGRAM FLIGHTS

      A mission to gather samples of the wind flowing from the Sun
and a mission to fly by three near-Earth comets have been selected
as the next flights in NASA's Discovery Program of lower-cost,
highly focused scientific spacecraft.

      The Genesis mission is designed to collect samples of the
charged particles in the solar wind and return them to Earth
laboratories for detailed analysis.  It is led by Dr. Donald
Burnett from the California Institute of Technology, Pasadena, CA,
at a total cost to NASA of $216 million.  Due for launch in
January 2001, it will return the samples of isotopes of oxygen,
nitrogen, the noble gases, and other elements to an airborne
capture in the Utah desert in August 2003.  Such data are crucial
for improving theories about the origin of the Sun and the
planets, which formed from the same primordial dust cloud.

      The Comet Nucleus Tour (CONTOUR) will take images and
comparative spectral maps of at least three comet nuclei and
analyze the dust flowing from them.  CONTOUR is led by Dr. Joseph
Veverka of Cornell University, Ithaca, NY, at a total cost to NASA
of $154 million.  It is scheduled for launch in July 2002, with
its first comet flyby to occur in November 2003.  This flyby of
Comet Encke at a distance of about 60 miles (100 kilometers) will
be followed by similar encounters with Comet Schwassmann-Wachmann-
3 in June 2006 and Comet d'Arrest in August 2008.

      "This was a very difficult selection, given the first-class
science proposed by all five teams," said Dr. Wesley Huntress,
Associate Administrator for Space Science at NASA Headquarters,
Washington.  "We picked two based on our distribution of resources
and the excellent fit of the timetables for these missions with
other robotic space science explorers.  Genesis will give us a
sample of the Sun as we are preparing to receive samples of a
comet and asteroid from other missions.  Meanwhile, CONTOUR will
help us better understand the breadth of the 'family' of comets,
which are believed to be quite individual in their properties."

      The selection of these missions is the second step of a two-
step process.  In the first step, NASA selected five proposals in
April 1997 for detailed four-month feasibility studies.  Funded by
NASA at $350,000 each, these studies focused on cost, management
and technical plans, including small business involvement and
educational outreach.

      The selected proposals were among 34 proposals originally
submitted to NASA in December 1996, in response to a Discovery
Announcement of Opportunity (AO) issued on September 20, 1996.  As
stated in the AO, the initial cost estimates were allowed to grow
by a maximum of 20 percent between the April selection and the
detailed final proposals.

      The investigations proposed in response to this announcement
(AO-96-OSS-02) were required to address the goals and objectives
of the Office of Space Science's Solar System Exploration theme or
the search for extrasolar planetary systems element of the
Astronomical Search for Origins and Planetary Systems theme.  A
selected mission was required to be ready for launch no later than
September 30, 2002, within the Discovery Program's cost cap of
$280 million total per mission, including development, launch and
operations.

      CONTOUR and Genesis follow four previously selected NASA
Discovery missions.  The Near Earth Asteroid Rendezvous (NEAR)
spacecraft was launched in February 1996 and returned sharp images
of the asteroid Mathilde from a distant flyby in June of this
year, on its way to orbit the asteroid Eros in early 1999.  The
Mars Pathfinder lander, carrying a small robotic rover named
Sojourner, landed successfully on the surface of Mars on July 4,
and since has returned hundreds of images and thousands of
measurements of the Martian environment.

      The Lunar Prospector orbiter mission to map the Moon's
composition and gravity field is scheduled for launch in January
1998, and the Stardust mission is designed to gather dust from
Comet Wild-2 in 2004 and return it to Earth, following a planned
February 1999 launch.

====================================================================

3) SEND YOUR NAME TO A COMET ABOARD THE STARDUST SPACECRAFT

from: Ron Baalke <BAALKE@kelvin.jpl.nasa.gov

Send Your Name on a Journey to a Comet aboard the Stardust Spacecraft

The Planetary Society helped NASA's Jet Propulsion Laboratory put
nearly 600,000 names on the Cassini spacecraft, and now the Society
is helping JPL put names on another historic spacecraft. When the
Stardust mission launches in February 1999, it will carry the names
of thousands of Planetary Society members and other space exploration
supporters. And, if you act before November 30, 1997, your name can
also be on this comet-exploring spacecraft.

Working with the Stardust Project, the Planetary Society is
collecting names to be placed on a microchip that will be mounted on
the Stardust return capsule. This capsule is part of a spacecraft
that will be rocketed into the tail of comet P/Wild-2, collect
samples of the comet's tail, and then return to Earth in January
2006.

To join Stardust on its journey, send your name, address, city,
state, country, postal code, and age (optional) to:

Stardust
The Planetary Society
65 North Catalina Avenue
Pasadena, CA 91106-2301

All entries must be received no later than Sunday, November 30, 1997.
The Society will also be posting a form for members and others to
submit their names on [their] web site.

We Are Stardust

Stardust will be not only the first United States mission solely
dedicated to a comet but also the first robotic return of cometary
dust and volatile samples. The culmination of more than a decade's
quest for a comet sample return, this mission will help us understand
more about the formation of our solar system, since comets are
well-preserved relics of the preplanetary material that accreted
in the outer fringes of the solar nebula. The scientific value of
having comet samples in hand cannot be overestimated.

Scientists consider comet P/Wild-2 to be a "fresh" comet. In 1974, it
was deflected by Jupiter's gravitational action from an earlier orbit
much farther out in the solar system. Samples from Wild-2 thus offer
us an exciting glimpse of the best preserved fundamental building
blocks out of which our solar system formed. And sample collection
will make use of exciting new aerogel material, the lowest density
solid material on Earth.

Fortuitously, a rare but opportune orbital design using an Earth
gravity assist allows Stardust to capture cometary dust intact -- and
parent volatiles as well -- at the incredibly low relative speed of
6.1 kilometers (about 4 miles) per second. With the aid of onboard
optical navigation, the flyby can take place at an encounter distance
as close as 50 kilometers (31 miles) from the comet's nucleus,
permitting the capture of the freshest samples from within the
coma parent molecule zone.. This rare trajectory imposes a very low
post-launch fuel requirement and enables launch by a Delta 2 launch
vehicle.

As an exciting bonus, Stardust will also collect interstellar dust,
recently discovered by Ulysses and confirmed by the Galileo mission.
In addition, a particle impact mass spectrometer provided by
Germany's DLR will obtain in-flight data on the compositon of both
cometary and interstellar dust, especially the very fine particles.

Increasing the yield of science data, Stardust's optical navigation
will take images of the comet's nucleus. The spacecraft's dust shield
will also provide coma dust spatial and temporal distribution, and
the X-band transponder may provide an estimate of comet Wild-2's
mass.

You can get more information on this mission to comet Wild-2 at the
Stardust Project's web site:

http://stardust.jpl.nasa.gov/



*
Date sent:        Wed, 22 Oct 1997 08:55:31 -0400 (EDT)
From:             Benny J Peiser <B.J.PEISER@livjm.ac.uk
Subject:          Massive Comet Blasted into Earth 370 Million Years ago
To:               cambridge-conference@livjm.ac.uk
Priority:         NORMAL

from: Bob Kobres <bkobres@uga.cc.uga.edu

From CNN.COM:

Massive Comet Blasted into Earth 370 Million Years Ago, Scientists Say

AP
20-OCT-97

SALT LAKE CITY (AP) New evidence suggests a comet slammed into
Earth 370 million years ago, blasting a huge crater into the sea
floor and triggering 1,000-foot waves that led to the extinction
of many species, scientists said Monday.

The crash may have been the first in a series of comet strikes
that forever changed life on Earth, including the extinction of
dinosaurs millions of years later.

Charles Sandberg, a geologist emeritus with the U.S. Geological
Survey, said Monday at a conference that the comet hit roughly
130 miles northwest of Las Vegas in southern Nevada when the
region was covered by ocean.

The force of the blast, dubbed the "Alamo Impact," created a
crater on the sea floor that was 30 to 50 miles in diameter,
ripping apart a reef on what was then the continental shelf,
Sandberg said at the annual meeting of the Geological Society of
America.

Waves 1,000 feet high spewed chunks of reef as large as a
half-mile-wide over an area in southern Nevada that was 120 miles
in diameter, he said.

Sandberg said he has roamed the area for several years and found
shattered blocks of the reef, turned into a kind of rock named
Alamo breccia. He said he and two other geologists John Warme of
the Colorado School of Mines and Jared Morrow of the University
of Colorado found evidence in June of the mass destruction
stretching some 60 miles farther than previously believed.

The crash, named after a town in the area, happened 3 million
years before one of the five greatest extinctions of life in
Earth's history at the end of the Devonian Period, when most
organisms lived in the ocean, the researchers said.

The evidence includes: crystals of shocked quartz that are sand
grains shattered by the force of the impact; a rock layer rich in
iridium, which is an element rare on Earth but common in
asteroids and comets; and sphere-shaped pieces of limestone-like
material created when small pieces of reef were blasted skyward
and melted, then fell to Earth, Sandberg said.

The area is rich in fossils that are 370 million years old.
Researchers in recent years also found a crater and similar
breccia rocks in other countries, suggesting the Devonian
extinction was caused by a series of comet strikes, Sandberg
said.

He said a comet that hit Jupiter in 1994 is evidence that
collisions by comets or asteroids are more than just theory.

On the possibility that a future comet could strike Earth,
Sandberg said. "It's something that we all have to think about."

He added: "There were impacts throughout time and mass
extinctions. ... And we can expect this again."

Some scientists are skeptical that cosmic impacts caused mass
extinctions, citing gradual die-offs of species as evidence that
climate changes due to other factors were to blame.

Paleontologist Kevin Padian of the University of California,
Berkeley told The Salt Lake Tribune that the timing of the Nevada
impact and the Devonian extinction are "close enough that you
want to look at it further. ... It's reasonable." He was not
involved in the research.
 

Bob Kobres

email= <bkobres@uga.cc.uga.edu
url= http://abob.libs.uga.edu/bobk
phone= 706-542-0583



CCCMENU CCC for 1997

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