PLEASE NOTE:
*
CCNet 126/2000 - 4 December 2000
--------------------------------
"List members might like to be appraised of the discovery of
what might well
be the largest known asteroid."
--Duncan Steel, 2 December 2000
Another cosmic dawn
Organic molecules in space we take for granted now
but not so long ago no one suspected they were there.
Stones from the sky was also an idea derided once,
but now we see that some came from the Moon and Mars.
"Panspermia' can mean life's everywhere, or that
it crosses space inside small rocks and grains.
We used to think that life could not be found
outside a narrow range of temperature and depth -
and so it goes, our knowledge of what's possible
grows now like crystals from a saturated fluid,
making a pattern which, while we may not understand,
only a bigot can deny. Now we can speculate how life,
so difficult to define, depends on quantum information,
itself a concept far from Planck's or Bohr's research.
The origin of galaxies may be a mystery still,
but stars have given up the secrets of their lives.
From large to small we've opened up our world
crossing a daunting mountain range of ignorance
to see a splendid view of snow-capped vistas
to test our new-found climbing skills once more!
Malcolm Miller
stellar2@cyberone.com.au
2.12.2000
(1) LARGEST ASTEROID DISCOVERED?
Duncan Steel <D.I.Steel@salford.ac.uk>
(2) A KUIPER-BELT GIANT?
John Wagoner <stargate@astromax.com>
(3) ANOTHER CANDIDATE FOR "PLANET X" SPOTTED
SpaceDaily, 4 November 2000
(4) ASTEROID/COMET CONFERENCE UPDATE
Andy Smith <astrosafe@yahoo.com>
(5) SOCIOLOGY VS SCIENCE
Sir Fred Hoyle & Chandra Wickramasinghe
<xdw20@dial.pipex.com>
(6) IDEAS ARE LIKE CHILDREN: THERE ARE NONE SO WONDERFUL AS YOUR
OWN
Konrad Ebisch <kebisch@zycor.lgc.com>
(7) AND FINALLY: "DRIED-UP SEA BEDS FOUND ON MARS"
Andrew Yee <ayee@nova.astro.utoronto.ca>
==========
(1) LARGEST ASTEROID DISCOVERED?
From Duncan Steel <D.I.Steel@salford.ac.uk>
Dear Benny,
List members might like to be appraised of the discovery of what
might well be the largest known asteroid. This was pointed out
to me by Mark Bailey.
Minor Planet Electronic Circular 2000-X02 dated 1st December...
http://cfa-www.harvard.edu/mpec/K00/K00X02.html
...indicates the discovery on 28th November of minor planet
(asteroid) 2000 WR106. The preliminary (circular) orbit solution
by Brian Marsden indicates a semi-major axis of near 43 AU and
hence a period of 282 years. The point of interest, however, is
the absolute magnitude H=3.5, indicating a size larger than the
previous record of H=4.5 for 1996 TO66.
H=3.5 indicates a size (diameter) of between about 500 and
1200 km, depending upon the assumed albedo. For comparison,
Pluto has a diameter near 2300 km.
If 2000 WR106 were towards the top end of that range (i.e. at
900-1200
km) then it might well be the largest known object classed as
being a
minor planet/asteroid. Ceres has a diameter of about 930 km.
On the other hand, despite the classification of objects in the
Edgeworth-Kuiper belt as being minor planets, we might consider
their physical nature to be closer to comets than rocky or
metallic
asteroids. Relatively high albedos might be produced by methane
frosts, or the like. This would indicate a size nearer to 500 km.
Still big, but not the biggest.
Whatever its actual size, 2000 WR106 ranks as one of the largest
discoveries in the solar system during the past century or so.
The only larger ones would appear to be Pluto's moon Charon
(about 1250 km in size; discovered in 1978) and Pluto itself
(2300 km, 1930).
Congratulations to Bob McMillan and Jeff Larsen, of the
Spacewatch
project at the University of Arizona, on their discovery.
Duncan Steel
====================
(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.
=====================
(3) ANOTHER CANDIDATE FOR "PLANET X" SPOTTED
From SpaceDaily, 4 November 2000
http://www.spacedaily.com/news/kuiper-00d.html
Tucson - Dec. 4, 2000
The Spacewatch Project at the University of Arizona has
discovered a
minor planet in the outer reaches of the solar system which
appears to
be the brightest known such object other than Pluto.
During routine scanning with the Spacewatch 36-inch telescope on
2000
November 28, observer R. S. McMillan was manually blinking the
displayed
scans in real time and noticed this relatively slow-moving
object. Its
rate of motion is too slow for the real-time software to detect;
normally the slower objects such as this one are found with
another
computer program that processes the data off-line.
The target was subsequently reobserved by J. A. Larsen, whose
observing
shift followed McMillan's. With their 12 observations spanning
three
days, The International Astronomical Union's Minor Planet Center
at the
Smithsonian Astrophysical Observatory in Cambridge, Massachusetts
determined a preliminary orbit by assuming the orbit is circular.
As of 2000 December 1, the MPC's orbit suggests that this object
is 43
times farther from the Sun than the Earth is, and is presently 42
times
farther from Earth than the Earth is from the Sun. With an
apparent
magnitude of 20 at those distances, the object would be the
brightest of
all 346 known Trans-Neptunian Objects other than Pluto.
Further observations of the object's position will be made in the
coming
weeks and months to improve knowledge of the orbital parameters
and
thereby the object's absolute magnitude, a parameter describing
the
object's brightness at a standard distance.
Since solar system objects shine by reflected sunlight, this
brightness
depends on the object's size as well as its reflectivity.
Therefore it
is not possible to give a definitive diameter for 2000 WR106.
However, if it has a reflectivity comparable to other minor
planets, its
diameter would be between 330 and 750 miles. This can be compared
to the
diameters of the largest known asteroid (1) Ceres of 570 miles or
(4)
Vesta of 320 miles. Pluto is at a distance comparable to that of
2000
WR106, and is 1,470 miles in diameter.
Brightness equates with ease of measuring the object's reflection
spectrum, so 2000 WR106 will no doubt be the target of
spectroscopy and
measurements of its thermal infrared flux (heat output). That
additional
information will allow a determination of its diameter.
The Spacewatch Project is a survey of the whole solar system,
from the
vicinity of the Earth's orbit all the way out to beyond the orbit
of
Neptune.
Copyright 2000, SpaceDaily
===========
(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
============================
* LETTERS TO THE MODERATOR *
============================
(5) SOCIOLOGY VS SCIENCE
From Sir Fred Hoyle & Chandra Wickramasinghe <xdw20@dial.pipex.com>
Dear Benny:
We do not wish to enter into a debate in your columns rebutting
critics
of panspermia. However, we would like to point out that the use
of
sociological arguments to discount emergent unpalatable trends in
science is not new. Not so long ago the Darwin-Wallace theory of
evolution was condemned using precisely such arguments. It is
time your
correspondents learnt the lessons of history that facts, not
opinions, are
all that ultimately matter.
Yours sincerely
Professor Sir Fred Hoyle
Professor Chandra Wickramasinghe
Cardiff Centre for Astrobiology
================
(6) IDEAS ARE LIKE CHILDREN: THERE ARE NONE SO WONDERFUL AS YOUR
OWN
From Konrad Ebisch <kebisch@zycor.lgc.com>
Dear Benny:
The 2000 December 1 CCNET is an exciting one. It actually
made me want
to comment on THREE items.
(1) The article "SCOTT HUDSON KEEPS EYE ON ASTEROID
TOUTATIS" from the
Daily Evergreen gives us a fine example of the reason why we need
to
have no confidence in the accuracy of items in the popular
press.
"The amount of energy released in an impact is roughly
equivalent to
100,000 megatons of TNT per kilometer of asteroid diameter,"
he said.
The nuclear bomb dropped at Hiroshima released the equivalent of
one-fiftieth of a megaton. "
A little third grade arithmetic applied here will show that a 1
millimeter planetoid will have the energy of five
hiroshimas. How did
we survive the Leonids? How many cities do we lose when the space
shuttle reenters?
(2) Then there was "Lunar Meteorite Ages Strongly Support
'Lunar
Cataclysm'" by Lori Stiles.
Sounds like good support for the planetoid-origin hypothesis that
says
that, at some long ago time, a large body was disrupted to create
the
asteroid population.
(3) And you sent the essay by Andrew Glikson, where I find
"...there can
be little doubt that life abounds throughout the
universe...." along
with a put-down for panspermia as an "Extraordinary
claim" and "a
philosophical notion rather than a scientific theory."
Here we have two hypotheses, both backed only by some
circumstantial
evidence that they might be possible, and neither with anything
like
solid evidence in favor. Yet the description of one makes
it sound like
an accepted theory, while the other sounds like a nut-case
notion.
In order to keep an open mind, we need to remember that, for each
of us,
it is true that "Ideas are like children--there are none so
wonderful as
your own."
Konrad Ebisch
===========
(7) AND FINALLY: "DRIED-UP SEA BEDS FOUND ON MARS"
From Andrew Yee <ayee@nova.astro.utoronto.ca>
[ http://www.sunday-times.co.uk/news/pages/Sunday-Times/stifgnnws01001.html
]
[From Sunday, December 3, 2000 Times of London.]
Dried-up sea beds found on Mars
NASA scientists have discovered ancient sea or lake beds on the
surface
of Mars that could once have harboured life, writes Jonathan
Leake.
The discovery is among the most significant concerning Mars so
far,
because such places are the most likely locations for fossils or
other
signs of past life.
NASA will announce the discovery in this week's edition of
Science with
the suggestion that the next generation of Mars landings should
be sent
to such areas.
This weekend a British group building a craft bound for Mars said
it was
already considering rerouting its vehicle, Beagle II, to land in
the
middle of one of the newly discovered sea beds.
Professor Colin Pillinger, an astronomer at the Open University
who
heads the Beagle II project, will also announce that he has
raised the
full £30M needed for the British mission.
He has just been offered £9M by the European Space Agency, with
the rest
coming from commercial sponsors. "We will launch in June
2003 and hope
to land on Mars on Boxing Day," he said.
The NASA discovery is based on images taken by Mars Global
Surveyor,
which has been orbiting the red planet for more than a year.
It is said to have sent back detailed pictures of rocks that
could only
have been created by sedimentation, in which particles sink to a
sea bed
and are compressed into rock.
Copyright 2000 Times Newspapers Ltd.
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