From: ch.steyaert@abbs.hanse.de (Chris Steyaert)
Newsgroups: sci.astro
Subject: Killer Comet Threath Dismissed 
Reply-To: ch.steyaert@abbs.hanse.de
Date: 15 Nov 92 20:50:00 MET
Distribution: sci
Organization: ABBS AstroMail, D-W 2121 Dahlenburg / Germany
X-Version: ZerUU V6.45c

Space News of November 9-15 contains some interesting news and interviews
with personalities directly involved in the "Swift-Tuttle 2126" case.

The headline reads:

    Funds To Track Comets Get Big Boost, but Killer Comet Threat Dismissed

...

  Scientists hope an expanded observation program will yield a more accurate
accounting of the largest comets and asteroids with orbits that could
intersect the Earth's. Astronomers see only five or six of an estimated
2,000 such objects each year, and there is no organized international
effort to track them.

...

  NASA's expansion of the program - adding $500,000 to a program of less
than $1 million - follows a January report to Congress that recommended
an international effort to build six ground-based telescopes designed for
comet detection. Morrison, who served as chairman of the Report of the NASA
International Near-Object Detection Workshop, said such telescopes could be
used to transform statistical estimates into hard facts.

  Most scientists agree that NASA's modest funding increase, earmarked for
upgrading telescopes and expanding their use, is proportionate to the need
to improve international detection and tracking of comets, both to improve
scientific knowledge and to keep an eye on any threatening objects.

...

  Astronomers expect Swift-Tuttle to return to its closest point to the sun
on July 11, 2126. However, if the prediction is off by 15 days, the comet
would hit the Earth on August 14, 2126, according to astronomer Brian
Marsden.

...

  The problem with Swift-Tuttle is that the comet seems to be throwing off
an unusually high amount of vapor and dust, producing a trusting action
that could distort its orbit.

  "The comet has shifted in a way we don't quite understand," Marsden told
Space News November 3. "It's very unusual".

...

  Other scientists however, are more confident in their prediction that
Swift-Tuttle will not hit the Earth.

  Donald Yeomans, research astronomer at NASA's Jet Propulsion Laboratory in
Pasadena, Calif., said the computational method he used accounted perfectly
for the 1737, 1862, and 1992 sightings. He predicts a 2126 return to its
closest point to the sun with a margin of error of just one day, eliminating
any possibility of an Earth collision.

Yeomans contends the comet's thrusting has no noticeable impact on its orbit.

  "The orbit is so large that it probably doesn't matter," he said in a
November 3 interview. "You can't push around a tank by a little tiny tail".

....

  "The surveillance may dispose of the whole problem," Marsden said. "Maybe
there is nothing to worry about next time, but we just have to watch out."


--
 Chris Steyaert
 Dr. Van de Perrestr. 83
 B 2440 Geel
 Belgium
 fax (32)14 22 13 73
 
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