PLEASE NOTE:


*

CCNet 121/2000 - 23 November 2000
---------------------------------


"NASA has not 'dropped the ball'; it has taken the initiative to
ensure that, however small the risk of harm, earth will be protected
from NEOs."
     --Peggy Wilhide, Associate Administrator for Public Affairs,
NASA


"As mid-November 2000 approached, meteor watchers were anxious to
learn if the dust stream models developed by Asher & McNaught would
work again. It seemed to be a testable question because -- according
to the models -- Earth was heading for the outskirts of three debris
streams. [...] The doubters became believers by day's end on Nov. 18th as
sky watchers reported strong meteor activity during all three encounters.
There is still some uncertainty about the exact times of the maxima and
their amplitudes, and how those compare to the predictions, but the
essentials are clear: Asher & McNaught-style models can predict
Leonid meteor showers, and for more than one year in a row."
        -- NASA News, 21 November 2000


(1) PREDICTING LEONID METEORS OFFICIALLY BECAME A SCIENCE LAST WEEKEND
    NASA Science News for November 21, 2000

(2) MYSTERY OF THE CHICXULUB CRATER: ANIMATION SHOWS LIQUID IMPACT
    Space.com, 22 November 2000

(3) BRITAIN JOINS EUROPEAN SOUTHERN OBSERVATORY (ESO)
    BBC Online News, 23 November 2000

(4) RESEARCHERS CLAIM TO HAVE FOUND ORDER IN THE DISTRIBUTION OF GEOLOGIC
'HOT SPOTS'
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(5) NO ASTEROIDS DROPPED (YET): NASA SAYS IT'S ON TARGET
    The Washington Post, 20 November 2000

(6) UK SCIENTISTS REPORT 'ALIEN' LIFE
    Environmental News Network, 22 November 2000

(7) FAST ROTATING ASTEROIDS
    P. Pravec  et al.

(8) RADAR OBSERVATIONS OF ASTEROID 2100 RA-SHALOM
    M.K. Shepard MK et al.

(9) SOLAR FLAR STUNS STARDUST
    NASA Science News for November 22, 2000

(10) MINING THE MOON, MARS & ASTEROIDS
    Planetary Science Research Discoveries (PSRD)

(11) SELF-ORGANISED NONSENSE
    Juan Zapata-Arauco <juanwisdomquest@yahoo.com>

(12) MICKEY AND THE GIGGLE FACTOR
     Phil Pleit <badastro@badastronomy.com>

(13) AND FINALLY: RECOMMENDED CHRISTMAS BOOK

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

(1) PREDICTING LEONID METEORS OFFICIALLY BECAME A SCIENCE LAST WEEKEND

From NASA Science News for November 21, 2000
http://science.nasa.gov/headlines/y2000/ast21nov_1.htm?list20392

LEONIDS GALORE

The art of predicting Leonid meteors officially became a science this
weekend as sky watchers around the globe enjoyed three predicted episodes of
shooting stars.

November 21, 2000 -- A bright moon, city lights and scattered clouds weren't
enough to keep the 2000 Leonid meteor shower at bay. Sky watchers who
ventured outdoors after midnight on Nov. 17th and 18th enjoyed sporadic
flurries of bright shooting stars numbering more than 200 per hour over
parts of Europe, Africa, and the Americas.

"I could see plenty of Leonids from [brightly-lit] downtown Boston,"
reported a reader on Saturday morning after a break in cloudcover briefly
revealed clear skies. "One meteor was even brighter than the Prudential
Building!"

This year's Leonid meteor shower consisted of three main episodes lasting
several hours each. There was a modest flurry of 50 to 100 meteors per hour
on Nov. 17th, followed by two more outbursts of 150 to 450 per hour on the
18th.

For many North Americans the times of greatest activity coincided with local
midnight when the constellation Leo was lying low on the eastern horizon.
Normally, low-hanging radiants are bad news because they make shooting stars
hard to see. In this case, however, sky watchers were treated to a vivid
display of Earthgrazing meteors. "Earthgrazers" are shooting stars that
emerge from just below the horizon and streak through the upper atmosphere
nearly parallel to the ground. They often display colorful halos and
long-lasting trails stretching 90 degrees or more across the sky.

"I [started watching] just before 11:00 pm on Friday," recounted Pierre
Martin from eastern Ontario. "Even with the Leonid radiant only 3 degrees
over the eastern horizon, it was obvious that some fairly high activity was
in progress. Several spectacular Earthgrazers appeared! .... A most
impressive orange-colored Leonid split the sky in half. It traveled 70
degrees. A multi-colored one at 11:55 pm really blew me away... It went from
vivid blue to green to orange before it extinguished and left behind a train
that lingered for 3 seconds."

The bright Moon was not a serious impediment to meteor watching as many
feared it would be. The Leonids were bright and they tended to streak far
from the shower's moonlit radiant.

At 2:45 am EST on Saturday, the Moon was high in the sky when Marjory
Moeller of Atol, NY, peered out her bedroom window. "I was immediately
rewarded by a long yellow meteor coming from the east," she said.
"Incredible sight! It would have been scary if I hadn't known what it was!"
Minutes later, Jeannie Moorhead of Warwick, NY, says "I saw an incredible
fireball explode as white as the moon -- it left a very thick trail that
remained in the sky for at least 5 minutes."

"I never expected a shower [to be] this good with the Moon up," added Ted
Nichols of the Astronomical Society of Harrisburg, PA. "During one 15 minute
interval I counted 45 meteors!" Altogether, he saw 275 shooting stars
between 10:30 pm on Friday and 3:30 am on Saturday.

But, not everyone was so fortunate.

"Like a lot of people in the southeastern US, all we saw in Louisiana were
rain showers -- about 10.5 inches worth at my house," lamented meteor
enthusiast Dave Hostetter. "We've been having a drought for a year and a
half -- I should have known which weekend would get rain!"

"The experts had predicted a strong Leonid shower... and by golly, that's
what happened here," agreed Kim Youmans in Georgia. "I can't remember when
it last rained so hard."

Fortunately for such observers, more Leonids are on the way. The
triple-peaked character of this year's shower appears to confirm new
research that predicts powerful Leonid meteor storms in the future.

"We're very confident that Leonid storms are coming in 2001 and 2002," says
forecaster David Asher of the Armagh Observatory in Northern Ireland. "Peak
rates during those years should reach at least 10,000 meteors per hour when
Earth passes through debris streams from comet Tempel-Tuttle."

Asher and collaborator Robert McNaught (Australian National University) drew
attention last year when they predicted the onset of a Leonid meteor storm
over Europe within minutes of the time it actually occurred. They had
carefully studied the orbits of myriad debris streams shed by comet
Tempel-Tuttle during its periodic 33-year visits to the inner solar system.
By noting the time when Earth passed close to one of those dust trails,
Asher & McNaught were able to forecast the 1999 Leonids with unheard-of
precision.

Astronomers have long regarded the Leonids as stubbornly unpredictable. The
failure of a major Leonid storm to appear in 1899, after scientists had
urged millions to stay up and watch it, was "the worst blow ever suffered by
astronomy in the eyes of the public," according to 19th-century astronomer
Charles Olivier. For the next hundred years astronomers fared little better
with hit-or-miss forecasts based on historical records.

As mid-November 2000 approached, meteor watchers were anxious to learn if
the dust stream models developed by Asher & McNaught would work again. It
seemed to be a testable question because -- according to the models -- Earth
was heading for the outskirts of three debris streams. Expectations were
tempered by the fact that the expected encounters were not very close. Earth
would pass half a lunar distance (LD) from one stream and 0.3 LD from two
others. Researchers suspected that these might be great distances compared
to the average width of a dust filament. If the outer reaches of the debris
fields were rarefied, observers might see very little meteor activity or
possibly none at all. (Note: one "lunar distance" or LD equals 384 thousand
km, the average separation of the Earth and the Moon.)

The doubters became believers by day's end on Nov. 18th as sky watchers
reported strong meteor activity during all three encounters. There is still
some uncertainty about the exact times of the maxima and their amplitudes,
and how those compare to the predictions, but the essentials are clear:
Asher & McNaught-style models can predict Leonid meteor showers, and for
more than one year in a row. Other researchers are already working to
improve the basic predictive models by, e.g., adding the effects of
radiation pressure on meteoroids and considering in detail the trajectories
of debris particles ejected from the parent comet. Decades of uncertain
Leonid meteor forecasts may soon be a distant memory.

Indeed, the future looks bright for Leonid meteors. In mid-November 2001
Earth will pass almost directly through three more Leonid dust streams.
Observers in the Americas, east Asia, Australia and the Pacific Ocean will
be favored for a good display. Even the Moon is expected to cooperate -- its
phase will be nearly New, affording dark skies for observers.

So, if rain or clouds (or simply a faulty alarm clock) spoiled your view of
the 2000 Leonids, don't despair. The best may be yet to come!

===============
(2) MYSTERY OF THE CHICXULUB CRATER: ANIMATION SHOWS LIQUID IMPACT

From Space.com, 22 November 2000
http://www.space.com/cgi-bin/email/gate.cgi?lk=T2&date=001122&go=/scienceastronomy/planetearth/asteroid_jello_001122.html

By Robert Roy Britt
Senior Science Writer
22 November 2000

When a giant space rock slammed into Earth 65 million years ago near the
present-day village of Chicxulub on the Yucatan Peninsula, not only did it
wipe out a lot of dinosaurs, it left behind a huge crater and, inside that
pock, an even bigger mystery.

A tourist in the jungle outside Chicxulub, about 200 miles (322 kilometers)
west of Cancun, wouldn't see any evidence of the crater, now buried in eons
of sediment. And she wouldn't suspect she was standing more than a half-mile
(1 kilometer) above the center of the crater.

But scientists found the crater a decade ago using seismic monitoring
equipment designed to hunt for oil. And now they have created an animated
computer model that shows how the crater might have formed -- and how it
would have left behind an otherwise inexplicable inner ring.

The collision

A comet or asteroid the size of a small city rocked the planet, sending
giant tsunamis across the ocean and earthquakes reverberating around the
globe. It also turned much of the Yucatan into mush, scientists suspect,
causing rock to behave like a thick fluid.

The animation of the Chicxulub event shows how the whole thing might have
happened, right up to the part where the ring mysteriously solidifies, like
terrestrial Jell-O in some standard crater mold.

The ring can't be explained. Similar rings have been observed inside other
craters on Earth and elsewhere in the solar system.

Clues to dino death?

The Chicxulub impact is widely believed to have triggered a mass dinosaur
die-off, either through a global firestorm or through massive long-term
environmental changes.

Figuring out how such a ring might form would help researchers understand
the chemical and physical processes that go on during an impact, and whether
and how such events might have caused mass extinctions in the past.

"This kind of research is crucial if we want to understand the environmental
knock-on effects of giant impacts," said Benny Peiser, a researcher who
focuses on neo-catastrophism at Liverpool John Moores University. "The truth
of the matter is that despite 20 years of impact research, we are still far
from knowing even the main mechanisms of impact-related mass extinctions."

Such research could also help humanity prepare for the effects of any
possible future impacts, and it might also shed light on how plain old
earthly landslides occur.

Hidden crater

Around 1980, Luis and Walter Alverez suggested that an impact might have
been responsible for the death of the dinosaurs. The race was on to find
evidence of a crater.

The Chicxulub crater was discovered 10 years later. Much of it lies under
the ocean, and all of it is hidden under 65 million years of sediment. The
crater is estimated to be 100 to 150 miles (160 to 240 kilometers) wide.

Gareth Collins, a postgraduate student at Imperial College in the U.K.,
presented the animation at the Geological Society of America's annual
meeting earlier this month. He detailed the Chicxulub event for SPACE.com:

The tremendous energy of the impact shattered the underlying bedrock into a
pile of rubble -- small rocks and large boulders. It also generated
vibrating acoustic waves, Collins suspects. These waves then supported the
weight of the rock, reducing friction deep down in the pile and allowing the
whole mess to slip around.

Collins calls the process "acoustic fluidization," and he likens it to a
pile of sand. If the pile is steep enough, the grains near the top of the
pile can slip. But the sand at the bottom has lots of weight pushing down on
it, creating friction and holding it in place.

"In order to allow the whole sand pile to move, some process must either
reduce the friction between the grains throughout the pile, or relieve the
weight of the overlying sand."

Collins says the same process relieved the weight in the Chicxulub rubble
pile, allowing otherwise solid material to slosh side-to-side and
up-and-down.

The crater collapsed, forming a towering mound in the center that was two or
three times the height of Mount Everest. An outer rim formed on the crater,
some 62 miles (100 kilometers) wide.

"The central uplift would then have collapsed itself to form a concentric
ring structure analogous to the ripple formed when a sugar lump is dropped
into a cup of tea," Collins said. "In the case of crater collapse, however,
the fluidization of the surrounding rock is only temporary -- once the
fluidization ceases, the collapse is halted and the internal concentric ring
structure remains."
 
It's this sudden solidification that leaves scientists scratching their
heads.

"This research is at a very early stage and hasn't overcome the biggest
difficulty," says Peiser, who was not involved in the work. "If the
punctuated material turns fluid and collapses within a very short time, how
can a central peak become frozen almost instantly in order to survive as a
feature instead of flatten out?"

Collins worked with Jay Melosh, a geophysicist at the University of
Arizona's Lunar and Planetary Laboratory, and others, to develop the
computer animation based on seismic data. Collins said that while geologists
are skeptical of the model, his colleagues who study asteroid impacts
generally agree with the idea. Peiser acknowledges that the concept is
"gaining currency."

But even those who support fluidization disagree on exactly how it occurs.
It might be caused by the heat of impact, some say, rather than by acoustic
waves.

Copyright 2000, Space.com

================
(3) BRITAIN JOINS EUROPEAN SOUTHERN OBSERVATORY (ESO)

From the BBC Online News, 23 November 2000
http://news.bbc.co.uk/hi/english/sci/tech/newsid_1035000/1035832.stm

Observatory coup for UK astronomers

British astronomers have been told they can join the project that will
operate the largest optical telescope in the world.

The government set out the details of its science budget on Wednesday and
indicated that substantial funds required for UK membership of the European
Southern Observatory (Eso) would be made available.

Eso's main facility is the Very Large Telescope at the Paranal Observatory
in Chile, due to become fully operational next year. Its advanced optics
technology is expected to give unprecedented views of the Universe - but it
does not come cheap.

The initial Eso joining fee is 70m with annual payments of 12m after that.
The Particle Physics and Astronomy Research Council (Pparc) will have to
contribute to these costs and this means some existing astronomy projects
may be cut back.

Larger British interests such as the UK Infrared Telescope or the Isaac
Newton Group of Telescopes on Hawaii could be threatened. As could UK
participation in a number of European Space Agency missions.

Positive response

Eso membership would give UK astronomers access to the optical array at the
La Silla observatory, also in Chile. But it is the VLT which is the most
exciting prospect.

It consists of four 8.2-metre and several 1.8-metre telescopes. These
telescopes can be used in combination as a giant interferometer to mimic a
truly massive, single telescope. And advanced optics ensure the VLT gets the
sharpest view of an object despite having to look through Earth's turbulent
atmosphere.

Professor Mike Edmunds, who recently chaired the UK Astronomy Review Panel
which set out a programme of opportunities and priorities for the next 10-20
years, said of the intention to join the Eso: "This is excellent news for UK
science and lays the foundation for cutting edge research over the next 10
years.

"British astronomers will be delighted by the government's rapid and
positive response to their case."

Science investment

Announcing the allocations from the science budget to the UK's seven
research councils, Trade and Industry Secretary Stephen Byers said research
into the role of genes would take a major share of the money available.

He said 252m would be invested by the councils in three key areas:

Genomics - 110m will allow researchers to develop new diagnostic tests and
new drugs based on the information gleaned in the human genome project;
e-science - 98m will develop the new high-power computing resources that
will increasingly be needed to handle the vast amounts of research data
shared around the world, principally over the net;

Basic technology - 44m will be used to fund new technologies such as
quantum computing, bio-engineering, photonics and nanotechnology - areas
which will form the basis of major new industries of the future.

In addition, the research councils would be given a further 100m for work
in their own specific areas, Mr Byers said. It is from this money that Eso
membership would be funded.
The announced money is part of an overall package of government science
investment amounting to 725m over the next three years.

"We have the potential to lead the world in many areas, but to do so will
require substantial investment," Mr Byers said.

Copyright 2000, BBC

===============
(4) RESEARCHERS CLAIM TO HAVE FOUND ORDER IN THE DISTRIBUTION OF GEOLOGIC
'HOT SPOTS'

From Andrew Yee <ayee@nova.astro.utoronto.ca>

Southern Methodist University
Dallas, Texas

Reporters may contact:
Ellen Mayou, SMU Public Affairs
(214) 768-7659, emayou@mail.smu.edu
   
November 15, 2000

SMU RESEARCHERS FIND ORDER IN THE DISTRIBUTION OF GEOLOGIC 'HOT SPOTS'

DALLAS (SMU) -- Researchers at Southern Methodist University have discovered
a symmetrical distribution for the "hot spots" on the Earth's surface.

Scientists have located 47 places on the Earth's surface where volcanic
activity unrelated to plate tectonics occurs. These areas include Hawaii,
Yellowstone, Iceland and the Galapagos Islands. These hot spots mark the
sites of ancient "mantle plumes" where huge amounts of volcanic material
rose from deep within the Earth. Today, residual material representing the
tails of these mantle plumes still comes up at these hot spots.

Although previous studies have recognized that hot spots tend to occur in
broad clusters, an orderly arrangement in their distribution had not been
reported. SMU geologists Rebecca Ghent and Douglas Oliver studied the
location of the major hot spots and determined that a disproportionate
number occur at latitudes between 20 and 30 degrees north and south of the
equator. Their observation became much more significant when the hot spots
were weighted according to the amount of volcanic material that they
produced. Statistical analysis shows that the likelihood of this
distribution arising by chance is less than one percent.

"This hints that there is something going on deep within the Earth that
hasn't been suspected before," Oliver said. Although it is widely accepted
that mantle plumes rise due to buoyancy, Oliver said that if buoyancy were
the only factor, this should result in a random distribution of hot spots.
The symmetrical distribution of hot spots on either side of the equator
suggests a process that channels material to the source region for the hot
spots 1,800 miles below the
surface. Oliver and Ghent are currently investigating processes within the
Earth that may be responsible for this phenomena.

Oliver and Ghent said their observation may shed light on other geological
phenomena, such as the development of superplumes, which are clusters of
mantle plumes arriving together at the Earth's surface. Scientists believe
that massive superplume events are responsible for some of the major changes
that have occurred on the Earth, such as the breakup of the supercontinent
known as Pangea into the present continents.

Ghent and Oliver presented their research Nov. 15 at the 112th annual
meeting of the Geological Society of America in Reno, Nevada.

[NOTE: Diagrams supporting this release are available at
http://www.smu.edu/~newsinfo/releases/00071.html]

=================
(5) NO ASTEROIDS DROPPED (YET): NASA SAYS IT'S ON TARGET

From The Washington Post, 20 November 2000
http://www.washingtonpost.com/wp-dyn/articles/A44717-2000Nov20.html

NO ASTEROIDS DROPPED

Letter to the Editor

Monday, November 20, 2000; Page A20

We at the National Aeronautics and Space Administration were astonished by
the charge that we may be "dropping the ball" in the search for asteroids
that may threaten earth [news story, Oct. 16].

While NASA welcomes the British plan to build a large facility for detecting
Near Earth Objects (NEOs) smaller than one kilometer in diameter, the search
remains largely a NASA-led effort.

That's not just a self-assessment. The British Task Force on Potentially
Hazardous NEOs prominently states that the United States is "doing far more
. . . than the rest of the world put together" and that the effort is
"progressing well" and has definitely not, as reporter T. R. Reid stated,
"fallen far behind schedule."

The Post article cited the task force estimate that as many as 2,000 Near
Earth Objects may be more than one kilometer in diameter. According to the
best current estimate, there are no more than 700 to 1,100 objects of this
size. The NASA-led effort has found almost half of all the large asteroids
that might threaten earth, including more than 100 in the past year alone.

Mr. Reid reported that NASA spends $2 million annually on locating and
identifying each of these objects; the true figure is nearly double that.

Long-period comets, which cause a modest fraction of the collisions suffered
to date on earth, cannot be predicted through the NEO survey. Their source
is the Oort cloud, a vast spherical cloud of comets at distances greater
than 10,000 times the distance of the earth from the sun. It is impossible
to detect objects the size of cometary nuclei at even a fraction of that
distance, but NASA has planned several missions to better understand these
comets.

NASA has not "dropped the ball"; it has taken the initiative to ensure that,
however small the risk of harm, earth will be protected from NEOs.

PEGGY WILHIDE
Associate Administrator for Public Affairs
National Aeronautics and Space Administration
Washington

2000 The Washington Post Company

==================
(6) UK SCIENTISTS REPORT 'ALIEN' LIFE

From Environmental News Network, 22 November 2000
http://www.enn.com/news/wire-stories/2000/11/11222000/upi_alien_40377.asp

Wednesday, November 22, 2000
By United Press International

Scientists in Wales said they discovered what may be a tiny form of
primitive alien life that a passing comet may have dropped into Earth's
atmosphere, London's Daily Mail newspaper reported today.

Researchers said that in the filter of a high-flying balloon operated by the
Indian Space Research Organization, they found a strain of bacteria unlike
anything on Earth. The bacteria were found at an altitude of 10 miles and
scientists from the ISRO, Cardiff University and the University of Wales
College of Medicine said it may have come from a comet on a close approach
to earth, according to the Daily Mail.

Prof. Chandra Wickramasinghe, who is based at Cardiff University, said the
discovery marked "the first time we have had direct evidence for the
hypothesis that comets seed life on other planets."

Wickramasinghe and astronomer Fred Hoyle suggested the theory of
"panspermia" more than two decades ago, that the seeds of life, either DNA
or microbes, could be carried by asteroids or comets and dropped off on
planets such as earth to germinate life.

The bacteria found in the balloon's filter "is a hitherto unknown strain,"
Wickramasinghe said. "It is so different from anything we've seen before
that there are only two possible explanations."

One, he told the Daily Mail, is that "organisms have been lifted from the
earth to great heights in the skies and have somehow multiplied there and
changed over time." The second, he said, is "that this is an example of
primitive alien life."

The newspaper said samples of the bacteria are under study at Cardiff's
Astrobiology Center, which Wickramasinghe and other scientists from ISRO,
Cardiff University and the College of Medicine have teamed up to form.

Wickramasinghe rejected suggestions that the bacteria might the result of
contamination by earthly organisms. He said ISRO had imposed stringent
sterile conditions aboard the balloon.

"The most recent geological evidence now suggests life on earth may be 4
billion years old," the professor was quoted as saying. "That is a very
significant time because it was a period when the earth was pounded by
comets and meteors."

But his theory is not universally accepted in scientific circles. The Daily
Mail quoted Alan Penny, an astronomer at Britain's Rutherford Appleton
Laboratory, as warning that "we would be cautious about jumping to
conclusions."

"Extraordinary claims," he said, "need extraordinary evidence."

Copyright 2000, United Press International
All rights reserved

============
(7) FAST ROTATING ASTEROIDS

Fast rotating asteroids 1999 TY2, 1999 SF10, and 1998 WB2
Pravec P, Hergenrother C, Whiteley R, Sarounova L, Kusnirak P, Wolf M
ICARUS 147: (2) 477-486 OCT 2000

An analysis of our photometric observations of near-Earth asteroids 1999
TY2, 1999 SF10,and 1998 WB2 has revealed their rotation periods to be 7.2807
+/- 0.0003, 2.4663 +/- 0.0005, and 18.8 +/- 0.3 min, respectively, Their
rotations are so fast that the bodies cannot be held together by
self-gravitation alone, and must therefore be monoliths. Their absolute
magnitudes, 23.1 +/- 0.3, 24.0 +/- 0.5, and 22.1 +/- 0.2, respectively,
indicate that they are small bodies with mean diameters in the range 60-120
m. The current statistics of asteroid spin rates vs size suggest that the
range where monoliths start to dominate among asteroids is below a diameter
of about 200 m, corresponding to H approximate to 22, as suggested by
P.Pravec and A. W. Harris (2000, Icarus, in press). (C) 2000 Academic Press.

Addresses:
Pravec P, Acad Sci Czech Republ, Inst Astron, CZ-25165 Ondrejov, Czech
Republic.
Acad Sci Czech Republ, Inst Astron, CZ-25165 Ondrejov, Czech Republic.
Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA.
Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA.
Charles Univ Prague, Astron Inst, CZ-18000 Prague, Czech Republic.

Copyright 2000 Institute for Scientific Information

=================
(8) RADAR OBSERVATIONS OF ASTEROID 2100 RA-SHALOM

Radar observations of Asteroid 2100 Ra-Shalom
Shepard MK, Benner LAM, Ostro SJ, Harris AW, Rosema KD, Shapiro II, Chandler
JF, Campbell DB
ICARUS 147: (2) 520-529 OCT 2000

We report Doppler-only (cw) radar observations of near-Earth Asteroid 2100
Ra-Shalom obtained at the Arecibo Observatory using a transmitter frequency
of 2380 MHz (12.6 cm) on 1984 Aug. 18-22. Weighted and filtered sums of cw
echoes achieve a maximum signal-to-noise ratio of 74 and cover the asteroid
in rotation phase. A weighted sum of all cw spectra gives an opposite
circular (OC) radar cross section of 1.13 +/- 0.40 km(2) and a circular
polarization ratio of 0.31 +/- 0.02. Inversion of echo edge frequencies
yields a convex hull with an elongation (maximum breadth/minimum breadth) of
1.15 +/- 0.03 and places a lower bound on the maximum pole-on dimension of
2.4 km/cos delta, where delta is the angle between the radar line-of-sight
and the asteroid's apparent equator. Ra-Shalom has one of the least
elongated pole-on silhouettes of the near-Earth asteroids for which similar
shape information from radar observations is available. Ra-Shalom's
effective diameter (diameter of a sphere with equal cross-sectional area) is
constrained to a range of 2.4-3.6 km. We use a two-component radar
scattering model to remove the "diffuse" contributions from Ra-Shalom's
radar cross section and obtain a surface bulk density estimate of 1.1-3.3 g
cm(-3). When compared with reported bulk densities and porosities of
meteorites, our results are consistent with either: (1) a C-class asteroid
with carbonaceous-chondritic composition, effective diameter 2.6-3.6 km, and
surface porosity <70%; or (2) an S-class asteroid with ordinary-chondritic
or stony-iron composition, effective diameter 2.4-2.6 km, and little or no
surface regolith. Ra-Shalom's near-surface roughness appears to be globally
heterogeneous. (C) 2000 Academic Press.

Addresses:
Shepard MK, Bloomsburg Univ Penn, Dept Geog & Geosci, Bloomsburg, PA 17815
USA.
Bloomsburg Univ Penn, Dept Geog & Geosci, Bloomsburg, PA 17815 USA.
CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA.
Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA.
Cornell Univ, Natl Astron & Ionosphere Ctr, Ithaca, NY 14853 USA.

===============
(9) SOLAR FLAR STUNS STARDUST

NASA Science News for November 22, 2000
http://science.nasa.gov/headlines/y2000/ast22nov_1.htm?list20392

One of the most intense solar radiation storms in decades temporarily
blinded NASA's Stardust spacecraft earlier this month.

November 22, 2000 -- Quick-thinking engineers and scientists helped NASA's
Stardust spacecraft survive a storm of high-energy particles from the Sun
after a recent solar flare.

Stardust -- a NASA mission to return samples from comet P/Wild 2 -- was only
1.4 AU (130 million miles) from the Sun on Nov. 8th when a powerful solar
flare erupted. Engineers from the Stardust team were a little worried, since
they had heard the resulting radiation storm was the fourth largest since
1976. A cloud of high-energy particles was heading for Earth and for
Stardust.

FULL STORY at
http://science.nasa.gov/headlines/y2000/ast22nov_1.htm?list20392

=============
(10) MINING THE MOON, MARS & ASTEROIDS

From Planetary Science Research Discoveries (PSRD)
http://www.soest.hawaii.edu/PSRdiscoveries/Nov00/mining.html

Mining the Moon, Mars, and Asteroids
Written by G. Jeffrey Taylor
Hawai'i Institute of Geophysics and Planetology 
 
An international group of scientists, mining and aerospace engineers, policy
makers, and other specialists met in Golden, Colorado to discuss the use of
space resources. Space Resources Roundtable II was held at the Colorado
School of Mines, and was sponsored by the School of Mines, NASA, and the
Lunar and Planetary Institute. Participants discussed lunar, martian, and
asteroidal resources, along with economic and legal aspects of using
extraterrestrial resources. This report focuses on lunar resources.
Manufacture of useful materials on the Moon, Mars, or asteroids requires
extensive use of what we know about those places through studies of lunar
samples and meteorites from asteroids and Mars. It is applied
cosmochemistry.

Lunar Solar Power

Energy specialists point out that we need alternatives to fossil fuels. They
give several reasons. There are environmental problems with burning carbon.
The traditional fuels will eventually run out. Perhaps most important,
increasing the standard of living in developing nations requires a huge
increase in the supply of energy.

Solar power has often been touted as an answer to the world's energy
problems. However, it is not very efficient. A given place on Earth is dark
half the time. Clouds and dust reduces the amount of solar energy by another
50%. And except near the equator, the low angle of sunlight causes loss to
the air, cutting the amount of energy by yet another 50%. All those
reductions amount to eight times less solar energy reaching Earth's surface
than arrives from the Sun.

The obvious thing to do is to tap the Sun's energy in space. The idea of
space power systems has been around since the late 1960s. New technology
makes it more attractive than it was at first. Its biggest problem is the
cost of launching lots of stuff from the ground to orbit. But suppose almost
all the needed materials were already there? David Criswell (University of
Houston) has been arguing for years that the materials are already there--on
the Moon. It just takes some manufacturing facilities to produce the needed
parts and pieces.

Solar power could be generated in space and beamed to the ground. The amount
of material needed to construct a power satellite is large, hence expensive
to transport from the surface of the Earth. It may be more cost-effective to
bring the ingredients from the lunar surface--or even use the Moon to
collect the solar power.

Criswell believes that solar power stations should be located on the Moon.
He proposes building them on the right and left sides of the Earth-facing
side of the Moon. This ensures a continuous supply of power to the earth.
Solar cells would collect sunlight and transmit the energy to microwave
transmitters. The microwave antennas would beam the energy to Earth, where
it would be received by other antennas on the ground. Criswell says that the
solar cells on the Moon would not need to be highly efficient. Instead, they
could cover a lot of real estate. The trick is to make the solar cells and
antennas on the Moon.

Alex Ignatiev, Criswell's colleague at the University of Houston, proposed a
solution. An expert in materials science, Ignatiev presented the basic
design for a robotic solar-cell maker. It would roll over the lunar surface,
leaving a trail of solar cells behind. As the surface passed beneath the
rover, concentrated sunlight would melt the surface. This would cool quickly
to make a smooth, glassy surface. Another system would extract silicon from
the lunar soil by a vaporization process and deposit it in thin films on the
glass surface. Depositing thin films requires a strong vacuum. The Moon
provides such a vacuum. The flimsy lunar atmosphere has a pressure about a
trillionth that of the Earth.

The result would be an extensive network of solar cells. They would probably
not be very efficient, but Ignatiev suggested that covering a large area
with solar cells would overcome that problem. Although Ignatiev has lots of
work to do to prove that the concept will work, most participants thought it
was a promising way to produce power on the Moon. Perhaps Earthlings will
prosper during the coming decades from an inexhaustible supply of solar
power from the Moon.

Lunar Alchemy: Dirt into Products

Schemes to extract oxygen from the lunar soil have been around for a long
time. Almost all of them also produce other products as well, such as iron
and titanium. Many require fairly high temperatures, hence a lot of energy.
A few processes use hydrofluoric acid. These do not need a high temperature,
but hydrofluoric acid is extremely toxic and corrosive.

Steve Gillette (University of Nevada, Reno) studies ways to separate
elements on Earth. He suggested using organic chemicals to extract useful
elements at a low temperature. Once lunar soil is dissolved into a mixture
of organic liquids, useful materials could be separated. For example,
silicon-based ceramics could be made at low temperature. These could be
useful for many purposes at a lunar base, including making molecule-sized
machines (so-called molecular nanotechnology). If the Moon becomes an
important part of Earth's commerce, cutting-edge technologies will be
essential.

Several scientists talked about their experiments on extracting oxygen,
using the more traditional high-temperature techniques. These included James
Blacic (Los Alamos National Laboratory), Giovanni De Maria (University of
Rome), and H. Yoshida and his colleagues (Tokyo Institute of Technology).
All use some kind of mechanism to fluff up moon dirt to make it easier to
react with hydrogen gas. (The experiments actually use simulated moon dirt.
Real lunar samples are too precious to use until a technology has been
tested thoroughly with fake moon dirt.) De Maria uses ultrasound to shake a
column of dirt. The others use the force of flowing hydrogen gas to make the
pile of dirt behave like a fluid. Blacic's apparatus ionizes the hydrogen,
making it reactive. The others heat the gas and dirt.

All the approaches produced water by reaction of the hydrogen with the soil.
On the Moon, this water could be used for life support. Most important, it
could be split into hydrogen and oxygen to use as rocket fuel. The
experiments also produced metallic iron. That could be used as a building
material or for electrical cables, if we could figure out an efficient way
to separate it from the rest of the dirt.

Larry Taylor (University of Tennessee) has been working on lunar samples
since the first batch was brought back from the Moon. He has also worked on
ways to remove oxygen from lunar soil. Recently, he has been working with a
team on understanding the optical properties of the lunar surface. This is
important to understanding many remote-sensing observations of the Moon.
While doing that work, he learned that the smallest soil grains, those
smaller than 20 micrometers, are coated with tiny particles of metallic
iron. The particles are only 10 to 100 nanometers across.
 
These two images show the distribution of iron in a collection of tiny lunar
soil grains. Those labeled 'plag' and marked with arrows (for plagioclase)
do not contain iron in their interiors. This is expected because lunar
plagioclase contains very little iron. However, the edges of the plagioclase
grains are decorated with blebs of metallic iron. This makes the plagioclase
magnetic. Arrows in the righthand image point to two plagioclase grains
coated with metallic iron which show up as bright rings. The other mineral
grains also contain iron blebs, but the coating is indistinguishable from
the iron oxide in the interiors.
 
What's that have to do with lunar resources? It is important for two
reasons. First, it may make it possible to filter out the finest lunar dust.
Rocky dust can be a health hazard to future workers on the Moon. It also can
collect on door seals, allowing air to escape from pressurized houses. The
minute iron particles make all tiny lunar grains magnetic. So, magnets will
be able to remove the dust from the air and could be used to clean surfaces.


Second, the magnetic properties of the tiny grains give us a way to
concentrate the finest dirt. By heating, the tiny iron grains will combine
into larger grains that can be separated. Also, hydrogen is a useful element
in lunar industry. Because it is delivered to the Moon by the solar wind, it
occurs in the surfaces of soil grains. A pile of small particles has a
greater surface area than a pile of large ones, so hydrogen is more abundant
in small grains than large ones. Thus, separating small grains also
concentrates hydrogen.

Drilling Holes in Planets

Some mining engineers are making important contributions to understanding
how to explore the subsurface and how to mine asteroids. Others are trying
to determine how to drill for water on Mars. Those places are very different
from Earth, so the engineers must modify their equipment and techniques.
Dale Boucher (Northern Centre for Advanced Technology, Sudbury, Ontario) has
used his vast experience in mine construction to devise a lightweight,
power-stingy drill to use on Mars. Jim Blacic has also been working on how
to drill on Mars. He and his colleagues have identified many components of
terrestrial drilling rigs that could be easily adapted for use on Mars. He
pointed out, however, that no existing drill could be used as is.

Leslie Gertsch (Michigan Technological University) described how an asteroid
could be mined, once a resource was identified on it. She brought up the
important point that the approach depends on the make-up of the asteroid.
For example, it might be composed of a mixture of ice and rock. The asteroid
might be weak, easily broken rock, or very strong rock. It might even be
made of metallic iron. This shows how important it will be to thoroughly
characterize an asteroid before deciding how to mine it.

The Future

People are eventually going to be working and living in space. Construction
and operation of lunar solar power stations may make that happen. Or perhaps
it will happen to support a thriving space tourism business. Whatever drives
it, there will be a need to use the resources available in space. It is too
expensive to drag all the needed ingredients up from the Earth. The
resources are available on the Moon, Mars, and asteroids. Participants in
the Space Resources Roundtable agree that we need to explore
extraterrestrial bodies for resources and to learn how to extract those
resources from them. Experts in the mineralogy and chemical composition of
extraterrestrial materials will play important roles in the search and
mining of space resources. Like Earth explorers through the ages, we must
live off the land and a new breed of scientist, the applied cosmochemist,
will be there to see it happen.

============================
* LETTERS TO THE MODERATOR *
============================

(11) SELF-ORGANISED NONSENSE
 
From Juan Zapata-Arauco <juanwisdomquest@yahoo.com>

Dear Benny: 
 
In the 11/11/2000 issue of New Scientist we can read an interesting opinion
written by Per Bak the creator of the theory of self-organized criticality:

"More spectacular is the application (of the theory of
self-organized criticality) to biology. Could it be that mass extinctions
are intrinsic outcomes of the dynamics of evolution? Try considering
them as co-evolutionary avalanches, where extinction of one species
leads to the extintions of others in a chain reaction. Compare this to the
traditional enviroment of scientific thought, dominated by the view that
nature is in a state of equilibrium and balance. This leads (sic) to the
unquestioned (sic) assumption that mass extinctions must be caused by
external cataclysmic events--such as meteorites (sic)." 
 
This can be reached in
"http://www.newscientist.com/opinion/opinion.jsp?id=ns226451" Best regards,
Juan

===============
(12) MICKEY AND THE GIGGLE FACTOR

From Phil Pleit <badastro@badastronomy.com>

Benny--

The article from the Rocky Mountain Collegian about asteroid impacts was
ostensibly a humor column. It was written in a student newspaper at Colorado
State University, and really shouldn't be taken seriously. It would have
been nice had the facts been straight, but a lot of that
stuff was exaggerated on purpose (though it wouldn't surprise me if some
people really do worry that mining the Moon might affect tides...).

Anyway, there was a disclaimer at the bottom that was not in the Exite News
version you published that should make this clear:

"Columnist Disclaimer: WARNING! The preceding column depicts acts that are
cruel and unusual toward hippies. Do not feed penguins suntan lotion for
fear of spontaneous combustion. Consult your local hypnotherapist for the
latest stock market information. If Cartman owns a Chewbacca action figure,
you must acquit. READ AT YOUR RISK."

I found it on the web at http://www.collegian.com/story.cfm?id=6076.

-Phil Plait,
      ex-humor columnist for a (different) student newspaper

==============
(13) AND FINALLY: RECOMMENDED CHRISTMAS BOOK

Good news for the undecided: Reader's Digest have made Duncan Steel's TARGET
EARTH one of their two recommended Christmas books. See:
http://shopping.readersdigest.com/rdsah/

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