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(meteorobs) Excerpt from "CCNet 126/2000 - 4 December 2000"
This issue was full of fascinating stuff about panspermia, ancient seabeds on
Mars, and more on the new giant Kuiper-Belt Object. And yet almost none of it
was strictly meteor-related. See the subscription info at the bottom for ways
of accessing these interesting items...
Lew
------- Forwarded Message
From: Peiser Benny <B.J.Peiser@livjm.acdot uk>
To: cambridge-conference <cambridge-conference@livjm.acdot uk>
Subject: CCNet, 4 December 2000
Date: Mon, 4 Dec 2000 12:39:41 -0000
CCNet 126/2000 - 4 December 2000
--------------------------------
[...]
(2) A KUIPER-BELT GIANT?
John Wagoner <stargate@astromax.com>
[...]
(4) ASTEROID/COMET CONFERENCE UPDATE
Andy Smith <astrosafe@yahoo.com>
[...]
============================================================
(2) A KUIPER-BELT GIANT?
>From John Wagoner <stargate@astromax.com>
SKY & TELESCOPE'S NEWS BULLETIN - DECEMBER 1, 2000
Ordinarily the discovery of a 20th-magnitude blip wouldn't be much cause
for excitement, but the one found early on November 28th is a special
case. If preliminary calculations are borne out by further observations,
the object now designated 2000 WR106 may prove to equal the size Ceres,
the largest asteroid. Located about 1.5 deg. south of the star Epsilon
Geminorum, the new find was spotted first by Robert S. McMillan and
later by Jeffrey A. Larsen (University of Arizona) with the 0.9-meter
Spacewatch telescope on Kitt Peak. They noticed its shifting position by
eye in a computer display of successive frames -- the motion was too
slow to be picked up by Spacewatch's automatic-detection software.
The object's actual size remains very uncertain in part because
astronomers aren't yet sure of its distance from the Sun. Right now the
best estimate is 43 astronomical units (6.4 billion kilometers), which
means it is a Kuiper Belt object (KBO) beyond the orbit of Pluto. An
object this far away takes nearly three centuries to circle the Sun, so
astronomers will need to observe it over many weeks or months for its
motion to betray the orbit's true character. However, according to Brian
G. Marsden (IAU Minor Planet Center), the assumed distance is unlikely
to change very much.
Another unknown is the albedo, or reflectivity, of the body's surface.
If 2000 WR106 is bright, like Pluto or Charon, then its diameter might
not
exceed 250 km, something akin to Vesta in size. But just the opposite
might be true. "Many people think KBOs have albedos closer to comet
nuclei -- very dark," William J. Romanishin (University of Oklahoma)
told members of the Minor Planet Mailing List. In that case, the
Spacewatch discovery could exceed 1,200 km in diameter. Ceres,
discovered almost exactly 200 years ago, is roughly 950 km across.
Apparently the object has escaped detection until now because it spent
many years lurking among the stars of the northern Milky Way. With
modern
electronic detectors, it is actually within the detection range of many
backyard telescopes.
============================================================
(4) ASTEROID/COMET CONFERENCE UPDATE
>From Andy Smith <astrosafe@yahoo.com>
Hello Benny and CCNet,
This report is to update you on our 2001 Conference planning, to give
you another data-point on our Asteroid/Comet (A/C) Emergency (ACE)
Scale, to express our appreciation to Michael Paine for his terrific
program, in Australia, and for his contribution to our understanding of
impact effects and to summarize what the Russian planetary defense
research seems to be saying.
Conference Planning
Our Asteroid/Comet Workshop, planned as part of the 2001 International
Space Development Conference (ISDC2001), Albuquerque, New Mexico (24-28
May) is taking shape nicely. We hope to summarize global progress toward
the goal of planetary emergency preparedness and to discuss, in-depth,
structural tsunami survival, impact meteorological effects, Tunguska
geomagnetic and other effects, LINEAR asteroid observatory activities,
the Deep Impact Program, the asteroid/comet threat on Mars and the Moon,
small metal asteroid mining, tree-ring extinction suggestions, etc.
ISDC2001 is on the Web at: www.isdc2001.org
The Conference will also have sessions on planetary geology, Mars
exploration and much more. It is being co-sponsored by the American
Institute of Aeronautics and Astronautics (AIAA) and the U.S. National
Space Society (NSS).
Good News
In addition to the A/CW, in May, we are pleased to announce that there
will be an extended program, concerned with planetary defense, included
in the SPACE 2001 conference (Albuquerque, August 28-30). It is on the
Web at: http://www.aiaa.org/calendar/sce01cfp.html ).
This conference is being sponsored by the AIAA and the U.S. Space
Technology Alliance (includes the space and defense organizations). We
cordially invite CCNet members to submit presentations (titles invited
ASAP and abstracts due by 7 January). We will also be organizing that
program and we will be happy to answer any questions and assist the
members, in any way we can.
Understanding The Danger
We have learned a lot about the effects and risks of A/C impact but we
still have a long way to go. In my last input to the CCNet, I indicated
that a third-of-a kilometer impact, in the Atlantic Ocean, might destroy
all of the Atlantic coastal cities, with super-tsunamis (annual risk in
the five-orders-of-magnitude range). In a subsequent CCNet note, Michael
Paine called my attention to an excellent report he had written, which
indicated that the critical size might be closer to a kilometer, based
on recent data. That note was very helpful to us and we are now
obtaining additional inputs.
We also want to call attention to the newly-formed (last few years)
Tsunami Society (TS). Volunteers like Michael and the volunteer
professional organizations, like the TS, the Spaceguard Foundation, the
Space Shield Foundation and the AIAA are helping us to get the answers
we need, to begin to prepare for defense and for emergency survival.
Asteroid/Comet Emergency (ACE) Data Point
It looks like the magnitude of the Mt.St.Helens explosion and
dust-generation event was equal to about a level-one(1) event on our ACE
Scale (equal to about a 20 megaton explosion and to the Tunguska and
Arizona/Barringer events). We are using this event to gauge the extent
of the dust hazard. Our ACE Scale, like the Richter Scale, is a simple
exponential destructive energy step-scale. Step one(1) represents 50
meter-range, high-density objects and the object width doubles with each
increasing step.
Russian Deflection Studies
The many studies completed thus-far, and reported by the Space Shield
Foundation, seem to be saying that we can probably deflect most
asteroids, using existing technology and hardware. Effective deflection
will require two-stage interaction, with the first interaction providing
a pocket, in the threatening object, to receive the deflection device.
The studies are also looking at other deflection alternatives (effective
against small NEO).
The first-generation defensive system could probably use systems similar
to Clementine, Deep Space 1 and NEAR and it would carry a low
megaton-range deflection system. Our most serious problem, now, is that
it will take about two years to prepare and launch a crude system - and
we haven't done much of the vital compatibility and employment research
and engineering. We strongly support all efforts which will reduce that
preparation time and improve the effectiveness of the deployment.
Because we have so little NEO data (about 1% of the 50 meter plus threat
population); any threat, in the next few decades, is likely to be a
complete surprise and require a desperate defensive reaction. For our
first generation system to do the best possible job, under such
circumstances, we need to expedite the needed studies.
Planetary Defense Advocacy Needed
We support present study activity, in the U.S., Russia and other
countries, aimed at impact/risk analysis, early-warning, defense and
civil emergency preparedness. The world astronomy team is making great
strides in the early-warning arena. Now, we need to organize and
strengthen the planetary defense and civil preparedness programs, using
public and expert advocacy. The year 2001 is a great year to look at
what we have done and what needs to be accomplished.
We again want to thank everyone contributing to meeting this - the
greatest technical challenge in history - and we invite you all to join
with us, at the conferences, next year.
Cheers
Andy Smith
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