PLEASE NOTE:


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CCNet DIGEST 22 May 1998
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(1) LATEST COMPUTERS WILL BOOST ASTEROID TRACKING EFFORTS
    Ron Baalke <R.BAALKE@kelvin.jpl.nasa.gov>

(2) DEEP IMPACT FROM AN INTERNATIONAL PERSPECTIVE
    Andrea Carusi <carusi@saturn.ias.rm.cnr.it>

(3) COMET SHOWER 35 MILLION YEARS AGO
    Phil Burns <pib@nwu.edu>

(4) SPECTACULAR FIREBALL
    Luigi Foschini <L.Foschini@fisbat.bo.cnr.it>

(5) MODELING METEORS
    Dick Spalding respald@sandia.gov

=============
(1) LATEST COMPUTERS WILL BOOST ASTEROID TRACKING EFFORTS

From Ron Baalke <R.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: Diane Ainsworth

FOR IMMEDIATE RELEASE                               May 20, 1998

LATEST COMPUTERS WILL BOOST ASTEROID TRACKING EFFORTS

NASA astronomers conducting a monthly sweep of the night sky
to identify previously unknown asteroids and comets will be able
to double their coverage and the number of discoveries they make,
thanks to new, state-of-the-art computer and data analysis
hardware.

The new equipment was purchased with funds from NASA, which
recently doubled its resources for near-Earth object research. 

The new real-time analysis system, which serves a fully
automated charged-couple device (CCD) camera and telescope atop
Mt. Haleakala, Maui, HI, is part of the Near-Earth Asteroid
Tracking (NEAT) project, based at NASA's Jet Propulsion
Laboratory, Pasadena, CA.  The new system features four 300-
megahertz processors that will be devoted solely to the enormous
amount of data coming back from the NEAT telescope on a nightly
basis.        

"This new system will speed up the processing of data and
allow us to analyze up to 40 gigabytes of data each night, or the
equivalent of nearly 70 CD-ROMs," said Dr. Steven Pravdo, NEAT
project manager at JPL.  "We will be able to double the amount of
sky we search each night, which is currently 500 square degrees,
as well as the number of new asteroids and comets we find during
each monthly observation cycle."   

Installed in 1995, the NEAT camera uses a very large, very
sensitive 4,096- by 4,096-pixel CCD chip.  The camera is located
on a 1-meter-diameter (39-inch) telescope operated by the U.S.
Air Force and located at an elevation of 3,000 meters (nearly 2
miles) above the Pacific Ocean. With stable climate, clear, dry
air and little light pollution, the NEAT tracking system has been
highly successful and continues to operate six days out of each
month.  With additional support, the project hopes to increase
this six-day observational run to 18 nights of observations each
month. 

Asteroids are considered relics of the formation of the
early solar system.  Most of them are rocky materials, with some
composed of nickel and iron. Most range in size from boulders up
to the largest main belt asteroid, Ceres, which is approximately
965 kilometers (600 miles) in diameter.  Comets, on the other
hand, are bodies of ice with embedded rock and organic materials
which heat up and become active, spewing gases and dust as they
approach the Sun. 

The NEAT telescope detects these small bodies by observing
the same part of the sky three times during an interval of about
one hour and comparing the three images to determine the location
of objects moving across the sky.  Since its inception, this
fully automated system has detected more than 25,000 objects,
including 30 near-Earth asteroids, two long-period comets and the
unique 1996 PW, which has the most eccentric orbit of all objects
discovered to date.  More information about NEAT discoveries,
along with black-and-white images of the objects, is available at
http://huey.jpl.nasa.gov/~spravdo/neat.html .   

Most recently, the NEAT team has discovered two new Earth-
crossing asteroids. One, designated 1998 HT31, is a relatively
small Apollo-type asteroid 270 meters (800 feet) in diameter; the
other, 1998HD14, is the 30th Aten to be discovered since JPL
astronomer Eleanor Helin first identified this class of asteroid
22 years ago, and the fifth discovered with the NEAT tracking
system.  Both are classified as potentially hazardous asteroids
because their orbits come within 5 million kilometers (3 million
miles) of Earth, or about 20 times the distance of the Moon. 
However, neither currently poses a threat to Earth.

"Atens are a rare class of asteroid because of their small
orbits, which are smaller than that of Earth's, and which never
allow them to wander far from our planet," said Helin, who is the
principal investigator of the NEAT program.  "1998 HD14 passed
within 5 million kilometers (3 million miles of Earth) just a
week after we discovered it on April 29.  This is relatively
close but poses no threat in the foreseeable future.  Atens are
of particular interest to us because they stay so close to
Earth's orbit."

Along with near-Earth asteroids, astronomers are also
interested in tracking long-period comets, which travel vast
distances from the Oort Cloud, a region far beyond Pluto's orbit,
which is believed to house trillions of incipient comets. These
objects travel in very long paths through the solar system, and
can appear unannounced, with no calling cards. 

"We are particularly interested in these comets because they
give us little time before appearing in Earth's vicinity," Helin
said. 

Astronomers dedicated to discovering and tracking near-Earth
objects are eager to find all of the potentially dangerous
asteroids and comets long before they are likely to approach
Earth.  For instance, the NEAT team at JPL is developing two new
CCD cameras and hopes to install them at Mt. Haleakala or other
facilities.   

"With additional telescopes, longer observational runs and
our new operating system, we will be able to detect 90 percent of
the Earth-crossing asteroids that are larger than 1 kilometer
(6/10ths of a mile) in diameter in the next 10 years," Pravdo
said.  "As our knowledge about these objects grows, we will be
able to provide better information which can be used in studies
of ways to divert Earth-crossers on threatening orbits toward
Earth."

NEAT was built and is being managed by the Jet Propulsion
Laboratory for NASA's Office of Space Science, Washington, DC.
JPL is a division of the California Institute of Technology in
Pasadena, CA.

===========
(2) DEEP IMPACT FROM AN INTERNATIONAL PERSPECTIVE

From Andrea Carusi <carusi@saturn.ias.rm.cnr.it>

Dear Benny,

yesterday I finally saw Deep Impact. Apart from the science flaws
(only a few, if compared with other similar movies) I think that the
major fault of this movie, otherwise very enjoyable, is the general
attitude towards the problem. It has already been remarked by Michael
Gerrard in a previous comment that the problems likely to be faced in an
impact scenario are many and Deep Impact addresses only a minority of
them (OK, it is a 2-hour movie) but, from my perspective as a non-US
citizen and as a scientist with a strong international connotation, I
have difficulty to accept that the movie is almost exclusively
US-centred.

We all know how much the United States are doing for the NEO cause, and
how little credibility other countries (not all of them) give to the
problem. However, it is surprising to see that the United Nations are
not even mentioned, that the "joint expedition" is composed only by
Americans (with an exception understandable in terms of political
correctness), that ESA -- which is likely to have in the future (thanks
to Rosetta) the best expertise in comet landing -- does not exist. I
suspect that the movie makers still think that only the US can address
and solve the impact threat, on behalf of the poor guys living
elsewhere.

The bad message that is given is comparable to the one of many western
movies where, after a long and dreadful story of villages and farmers
menaced by ugly indians, in the end the US cavalry come and solve the
problem killing all of them. I would call this an "arrivano i nostri"
(ours are coming) plot.

I don't like this scenario; not because I have anything against the
US, but because it demonstrates that we have still a long way ahead
before understanding and deeply accepting the simple fact that the NEO
threat could not be faced by ANY single nation. The recent, unfortunate
positions of NASA and of the NRC on the problem of secrecy give further
support to this uncomfortable consideration. From a different point of
view, it is also interesting to consider that the actions initiated in
the movie by the US government do fail! The threat was not told to
anybody else (apart from Russia?), two strategies failed and nobody else
was consulted, not even invited to propose other remedies: in some sense
this is also a message, it reminds me of something...

There is a point in the movie where the President admits that there are
no more hopes, and that everywhere in the world everybody thinks for
himself. Another very dangerous thinking: no man is an island. I would
like very much to see an American movie where Americans may forget, at
least once, to belong to the richest and most powerful country in the
world and make every effort to share with the other nations the load of
saving humankind.

I repeat: these comments are not meant to diminish the role that the US
play in this game but, rather, to alert the US scientists (and
non-scientists) that the "we do all" attitude depicted in Deep Impact
is wrong and dangerous and does not help the growth of a strong
international consensus on the countermeasures to be adopted, even if
only dealing with the construction of telescopes.  On the contrary, it
would be useful if the US people might take every opportunity,
especially
in their own country, to stress the necessity of a coordinated
international action.

Andrea Carusi
IAS, Area Ricerca CNR Tor Vergata
Via Fosso del Cavaliere
00133 Roma, Italy
Phone: +39-6-49934447 Fax: +39-6-20660188
E-mail: carusi@saturn.ias.rm.cnr.it

========================
(3) COMET SHOWER 35 MILLION YEARS AGO

From Phil Burns <pib@nwu.edu>

Today's issue of SCIENCE (May 22, 1998; v. 280, n. 5367) contains an
article entitled "Geochemical Evidence for a Comet Shower in the Late
Eocene" by Kenneth Farley, Allesandro Montanari, Eugene Shoemaker, and
Carolyn Shoemaker. They suggest that the Popigai crater in Siberia and
the Chesapeake Bay crater were created by the impact of separate members
of a comet shower about thirty five million years ago. 

A brief precis appears at

     http://www.msnbc.com/news/167457.asp

and the abstract and full text of the SCIENCE article are available to
Science Online subscribers at

     http://www.sciencemag.org/content/current/

-- Phil "Pib" Burns
   Northwestern University, Evanston, IL.  USA
   pib@nwu.edu
   http://pibweb.it.nwu.edu/~pib/

====================
(4) SPECTACULAR FIREBALL

From Luigi Foschini <L.Foschini@fisbat.bo.cnr.it>

Dear Friends and Colleagues,

please, enjoy yourself with this spectacular image of a bolide, made by
Roberto Baldini (email:antares@provincia.ra.it) of Antares Amateur
Astronomers Group (Cotignola, RA, Italy).

The "photo" was made on May 15th, 1998 at 23h 21m 50s UT. Place: near
Bagnacavallo (RA), Italy (lat. 44 deg 30' N; lon. 12 deg E
approximatively).

Really the image was made, soon after the *visual* observation, by using
a computer software. It is a photo-like drawing, not just a photo, based
on a visual observation.

Greetings,

Luigi

dr. Luigi Foschini
CNR - Institute FISBAT
Via Gobetti 101, I-40129 Bologna (Italy)
tel. +39 51 639.9620/9622; fax  +39 51 639.9654
E-mail: L.Foschini@fisbat.bo.cnr.it
WWW: http://www.fisbat.bo.cnr.it/homepp/dinamica/foschini.html

====================
(5) MODELING METEORS

From Dick Spalding respald@sandia.gov

re: WHO CAN HELP RUSSIAN STUDENTS TO MAKE AN IMPACT

I offer the following suggestion. In Moscow, there is a group who
have been developing models for the processes involved in large
meteoroid impacts into the atmosphere, with special emphasis on
visible-light radiations. The group is under Prof. Ivan Nemtchinov at
the Institute for Dynamics of Geospheres, Russian Academy of Sciences.
This work has been undertaken to help us at Sandia National Laboratories
in Albuquerque, New Mexico interpret the meaning of visible-light
flashes of large impacts recorded by the satellite sensors which we
designed.

Although Prof. Nemtchinov may be unavailable just now because he is
traveling to the US, someone else at IDG/RAS can probably help. Another
person there who has been very close to the modeling development
activity is Valery Shuvalov.

Good luck!                              Dick Spalding

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