PLEASE NOTE:


*

CCNet DIGEST, 5 March 1999
--------------------------


     QUOTE OF THE DAY

     "We do need a number of telescopes at different longitudes and
     different latitudes in order to have a complete survey. You can
     think of it this way: If an asteroid should come by while one side
     of the earth is facing it, we want to have a telescope that can
     see it. (It is a) very good idea (to set up telescopes in the
     Southern Hemisphere, especially Australia). Should an asteroid
     pass in an extreme southerly direction, we could easily miss that
     one" (Paul Chodas, JPL, 3 March 1999)


(1) COOKING UP A NEAR-EARTH ASTEROID
    INSCiGHT, Academic Press.
    http://www.academicpress.com/inscight/03041999/grapha.htm

(2) A CALL TO MONITOR KILLER ASTEROIDS
    MSNBC
    http://www.msnbc.com/news/spacenews_front.asp

(3) RESEARCHERS UNCOVER REVOLUTIONARY NEW PHYSICS DISCOVERY
    Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>

(4) DESPERATELY SEEKING PSYCHE FAMILY
    D.R. Davis*), P. Farinella, F. Marzari, PLANETARY SCI INST SJI

(5) SOILS FOR SPACE-BASED AGRICULTURE
    M.N. Mautner, LINCOLN UNIVERSITY

(6) ASTEROID ROTATION STATS
    J.R. Donnison*) & M.P. Wiper, UNIVERSITY OF LONDON

=======================
(1) COOKING UP A NEAR-EARTH ASTEROID

From INSCiGHT, Academic Press.
http://www.academicpress.com/inscight/03041999/grapha.htm

Thursday, 4 March 1999, 5 pm PST

Cooking Up a Near-Earth Asteroid

By Mark Sincell

Take two of the many asteroids orbiting between Mars and Jupiter. Smash
them together into fairly small pieces. Then add sunlight. This is the
new recipe, proposed in tomorrow's Science, for the surprisingly large
numbers of asteroids that pass by Earth every year.

Scientists generally agree that gravitational tugs from Mars, Jupiter,
and Saturn can yank asteroids out of the main belt and into near-Earth
orbits. But for this to happen, an asteroid must encounter a resonance,
which is like an eddy of chaotic gravitational fields that bounces
asteroids out of their old orbits. The resonances that create
near-Earth asteroids are found along the orbit of Mars, but there
aren't enough to explain all the observed near-Earth asteroids, says
Paolo Farinella, an astrophysicist at the Universita di Trieste in
Italy. Now Farinella and his colleague D. Vokrouhlicky, a space
scientist at Charles University in Prague, Czech Republic, suggest that
the Yarkovsky effect -- a little known process first studied over 100
years ago by a Russian engineer -- may solve this long-standing
conundrum by funneling more asteroids into the known resonances.

Here's the idea. As the sun shines on an asteroid, it warms the surface
-- except for crevices and other shaded parts of the surface. The
hotter regions of the surface then push on the asteroid by radiating
infrared light. Theoretical models suggest that these tiny forces can
gradually shift the asteroid's orbit, and, if the calculations are
correct, this wandering ups the odds of the asteroid crossing Mars's
orbit and falling into a resonance. The Yarkovsky effect works most
efficiently on objects smaller than 20 kilometers, so Farinella has
proposed that the Yarkovsky effect causes the rubble of large asteroids
to drift into resonances, which kick some of the smaller pieces into
near-Earth orbits.

"Farinella's work is an important advance," says Andrew Cheng, an
astronomer at the Applied Physics Laboratory in Laurel, Maryland, "but
we are still very far from a complete understanding" of the processes
that create near-Earth asteroids. Cheng cautions that while the
Yarkovsky effect may work in concert with collisions and gravity to
bring asteroids into near-Earth orbits, no one has found hard evidence
to support the theory that the main belt spawns near-Earth asteroids.

(c) 1999 The American Association for the Advancement of Science

===================
(2) A CALL TO MONITOR KILLER ASTEROIDS

From MSNBC
http://www.msnbc.com/news/spacenews_front.asp
                 
British MP urges government to take lead role in a global effort
                                  
MSNBC STAFF AND WIRE REPORTS

LONDON, March 3 —  A member of Britain’s Parliament is launching a
campaign for closer monitoring of massive asteroids that could kill
billions of people if they crashed into the Earth.

"AT PRESENT an asteroid could hit the Earth and we would have about 20
seconds’ notice," Lembit Opik, a member of the minority Liberal
Democrats, told a news conference Wednesday. "It isn’t long enough to
say the Lord’s Prayer."
 
Opik’s Lithuanian grandfather, an astronomer, had an asteroid named
after him.
 
Opik is urging the British government to set up an asteroid-tracking
telescope, based in either Namibia or Australia. NASA’s 1992 Spaceguard
Survey Report recommended establishing six such dedicated telescopes
around the globe to identify and track the 2,000 or so near-Earth
asteroids, minor planets measuring more than a kilometer (0.6 mile)
across that come close to Earth’s orbit.
 
Closer monitoring of asteroids would give scientists better data to
calculate the course of near-Earth objects. For example, almost exactly
a year ago, astronomers issued an alert warning that an asteroid known
as 1997 XF11 might hit Earth in 2028 — but additional data led to the
conclusion that the object would just miss our planet.
 
If an asteroid were ever found to be on a collision course with Earth,
scientists hope to have enough lead time to figure out a way to deflect
its course.
                                 
SCIENCE FICTION AND FACT
 
Asteroid interception is still the stuff of science-fiction movies like
"Armageddon" or "Deep Impact," but Paul Chodas, an astronomer at NASA’s
Jet Propulsion Laboratory, said the need for a bigger
asteroid-monitoring network was a scientific fact.
 
"We do need a number of telescopes at different longitudes and
different latitudes in order to have a complete survey," he told MSNBC.
"You can think of it this way: If an asteroid should come by while one
side of the earth is facing it, we want to have a telescope that can
see it."
 
Last year NASA announced that it would step up its efforts to track
near-Earth objects. Chodas noted that there were already several
monitoring systems in the United States, one in Europe and one under
development in Japan.
 
He said it was a "very good idea" to set up telescopes in the Southern
Hemisphere, especially Australia. "Should (an asteroid) pass in an
extreme southerly direction, we could easily miss that one," he said.
                                 
POTENTIAL DISASTER
 
Astronomer Mark Bailey, director of Northern Ireland’s Armagh
Observatory, said a large asteroid hitting Earth would cause disaster
on a scale comparable with the one which scientists believe wiped out
the dinosaurs 65 million years ago. It doesn’t matter where on Earth it
hits. The dust thrown into the atmosphere would cool the earth
drastically and cause a temporary shutdown of agriculture," he said.
"It could mean the loss of about a quarter of the world’s population."
 
A globally threatening impact is likely to occur only once in 100,000
years. But because of the mass destruction such an impact would cause,
the risk of any given citizen of the United States dying because of an
asteroid impact has been estimated at 20,000 to one, Bailey said.
 
Jonathan Tate, director of the lobbying group Spaceguard UK, said
setting up the proposed telescope, thus encouraging other developed
countries to take similar steps, would cost about $15 million over 10
years.
 
"It is only sense to do something about this," Tate said. "If the
Americans could get to the moon in 10 years, we can solve this problem
in less than 10 years."
                                 
MSNBC’s Alan Boyle and Reuters contributed to this story.

Copyright 1999, MSNBC

=================
(3) RESEARCHERS UNCOVER REVOLUTIONARY NEW PHYSICS DISCOVERY

From Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>

Clemson University
Clemson, South Carolina

CONTACTS:
Donald Clayton, (864) 656-5299, (864) 656-0805 (fax)
Weihong Liu, (423) 574-4707
Alexander Dalgarno, (617) 495-4403

WRITER: Sandy Dees, (864) 656-4193

2-25-99

RESEARCHERS UNCOVER REVOLUTIONARY NEW PHYSICS DISCOVERY

Clemson teams with Oak Ridge National Laboratory and Harvard

CLEMSON -- Astrophysicists at Clemson University, Oak Ridge National
Laboratory and Harvard University discovered a new chemical sequence
during research into how large carbon molecules might form in exploding
stars known as supernovae.

The finding is casting doubt on the long-held chemical equilibrium
theory and clearing the way for a new field -- kinetic chemistry.

"We believe we have uncovered new truths of chemistry," said Clemson's
Donald Clayton, an internationally known theoretical astrophysicist.
"Some controversial aspects of supernovae, including information about
their core or the amount of radioactivity they generate, can be better
evaluated with this kinetic chemical theory." The research team
included Clayton, ORNL's Weihong Liu and Harvard's Alexander Dalgarno.

Their work, to be published in the Feb. 26 issue of "Science," has
far-reaching implications for physics, chemistry, astronomy, meteoritic
and planetary sciences. "Science" is the weekly journal of the American
Association for the Advancement of Science.

Scientists had previously believed it impossible to convert cosmic
carbon from a hot gas into a solid if there was more oxygen than carbon
present. Conventional theory held that any free carbon atoms in the
supernova gas should have reacted with the more abundant oxygen atoms
to form carbon monoxide.

But the researchers discovered that supernova radioactivity breaks the
strong chemical bond that holds carbon and oxygen together. Energetic
electrons and ions allow carbon atoms to escape the pairing mechanism,
leaving plenty of atomic carbon that can condense into solid particles
and eventually be ejected from the supernova.

The breakthrough that led to the research are tiny grains of "star
dust" found inside meteorites that fell to earth about a million years
ago.

"These supernova graphite particles are the oldest material fossils
that humankind can study, older than our solar system, at least twice
as old as the oldest rocks on Earth and also twice as old as the
earliest biological fossil algae found on Earth," said Clayton, who
first predicted the clues that would identify the starry fossils.

                               END

Order Information:

ARTICLE #6: "Condensation of Carbon in Radioactive Supernova Gas" by D.
D. Clayton at Clemson University in Clemson, SC; W. Liu at Oak Ridge
National Laboratory in Oak Ridge, TN and at U. of Tennessee in
Knoxville, TN; A. Dalgarno at Harvard-Smithsonian Center for
Astrophysics in Cambridge, MA.

IMAGE CAPTION: [http://clemsonews.clemson.edu/pix/claytonweb.GIF]

Clemson astrophysicist Donald Clayton and research colleagues believe
they have uncovered "new truths of chemistry."

=========================
(4) DESPERATELY SEEKING PSYCHE FAMILY

D.R. Davis*), P. Farinella, F. Marzari: The missing Psyche family:
Collisionally eroded or never formed? ICARUS, 1999, Vol.137, No.1,
pp.140-151

*) PLANETARY SCI INST SJI,620 N 6TH AVE,TUCSON,AZ,85705

Asteroid 16 Psyche, the largest M-type asteroid, is widely considered
to be the collisionally exposed core of an similar to 500-km diameter
differentiated parent body which was similar to asteroid 4 Vesta.
However there is no dynamical family associated with Psyche nor are
there spectroscopic data for the existence of the mantle or crustal
material from the parent body. The usual explanation for the missing
material requires that the Psyche parent body was collisionally
disrupted early in solar system history, followed by collisional
grinding of the family down to below the current observational limit
sizes. We test the exposed core hypothesis for the origin of Psyche
using a numerical code that simultaneously calculates both the
collisional evolution of the asteroid belt and the model family
formed by the breakup of the Psyche parent body (PPB). We find that it
would take a projectile about 300-350 km in size to thoroughly disrupt
a 500-km asteroid (the estimated size of the PPB), and that the
probability of such an event occurring in the first 500 Ma of solar
system history is only about 1%. While the Psyche model family is found
to have been significantly ground down subsequent to its formation,
there should be several tens of survivors from the mantle and crust
larger than similar to 10 km that should be spectroscopically
detectable by current technology. Although only a small fraction of the
asteroids larger than 10 km have been discovered and observed
spectroscopically to date, none have been identified as potential
survivors from the PPB (Burbine et al. 1996, Meteor: Planet. Sci. 31,
607-620). Given the low probability of the disruption of a Vesta-like
body and the lack of either dynamical or observational confirmation of
a family or material from the parent body, we think it more likely that
Psyche has possibly been shattered by impacts but not catastrophically
disrupted. In this case, it would be a plausible candidate parent body
for the mesosiderites. The exposed-core scenario more probably applies
to other, smaller (diameter less than or similar to 100 km) M-type
asteroids, which could be the parent bodies of the iron meteorites.
However, this interpretation raises the interesting problem of why
among the larger asteroids only Vesta and the PPB would have been fully
differentiated. (C) 1999 Academic Press.

===============
(5) SOILS FOR SPACE-BASED AGRICULTURE

M.N. Mautner: Formation, chemistry and fertility of extraterrestrial
soils: Cohesion, water adsorption and surface area of carbonaceous
chondrite. Prebiotic and space resource applications. ICARUS, 1999,
Vol.137, No.1, pp.178-195

*) LINCOLN UNIVERSITY,DIV SOIL PLANT & ECOL SCI,LINCOLN,NEW ZEALAND

Following microbial and plant responses to Murchison CM2 meteorite
nutrients, further soil fertility parameters are examined. Cohesion of
the matrix is tested by dissolving in acidic disaggregation agents, 0.4
M CH3COOH, 10% HNO3, H2SO4 (pH 3), 50%H2O2 + H2SO4 (pH 3), and
saturated CO2 solution. The responses suggest that carbonates and the
organic polymer contribute as cementing agents, and that enhanced
disaggregation by H2O2 and diminished disaggregation in saturated CO2
solutions may contribute to the weathering of carbonaceous meteorites
in martian or early Earth environments, respectively. The cation
exchange capacities (CEC) of the solid (7.2 +/- 0.8 meq/100 g) and
powdered Murchison (7.8 +/- 1.5 meq/100 g) are comparable. The cation
exchange capacity is not reduced by oxidation or acetylation,
suggesting that the binding sites of exchangeable cations are mostly
inorganic. The CEC correlates with water vapor adsorption similar to
that for terrestrial soils. For example, at 20 degrees C and P(H2O) =
10.8 mbars, 17 mg/g H2O is adsorbed on Murchison (CEC = 7.2 meq/100 g)
and only 0.6 mg/g on Allende (CEC = 0.4 meq/100 g). Under these
conditions 13 H2O molecules are adsorbed per surface cation in
Murchison and 8 H2O molecules/cation in Allende, similar to 9 H2O
molecules/cation in terrestrial soils and in montmorillonite.
Adsorption isotherms on the Murchison are convex at low pressures,
indicating strong bonding of the first water molecules, and concave at
high pressures, indicating a broad pore size distribution. Isotherms at
278, 293, and 311 K yield isosteric heat of adsorption of 56.5 +/-
2.5 kJ/mol at 4-8 H2Oadsorbed molecules/cation, similar to that for
montmorillonite. The isotherms yield a specific surface area of S-w =
37 x 10(3) m(2)/kg for Murchison, larger than the 19 x 10(3) m(2)/kg of
pure serpentine, suggesting contributions, in addition to the main
serpentine-like phyllosilicates, by components equivalent to a 9-12%
smectic clay-like content. Water evaporation curves from meteorite
surfaces display the multistage behavior typical of soils, with
slow rates for the evaporation of surface-adsorbed water. The gas
adsorption data allow an assessment of gas-adsorbed water equilibrium
in the solar nebula and suggest possible self-catalytic effects in
adsorption/aqueous alteration processes. The observed fertility
indicators and biological effects support the potential of carbonaceous
chondrites to support early biological processes and as soils for
space-based agriculture. (C) 1999 Academic Press.

============================
(6) ASTEROID ROTATION STATS

J.R. Donnison*) & M.P. Wiper: Bayesian statistical analysis of asteroid
rotation rates. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY,
1999,  Vol.302, No.1, pp.75-80

*) UNIVERSITY OF LONDON GOLDSMITHS COLL,DEPT MATH & COMP SCI,NEW
   CROSS,LONDON SE14 6NW,ENGLAND

Asteroid rotation rates have been analysed by many authors in the past,
and one or more Maxwellian distributions have been fitted for various
diameter ranges and taxonomic classes. The statistical results and
physical interpretations of the models have varied widely. In this new
approach we use Bayesian statistics to determine the separation of the
larger asteroids, which are fitted with a single Maxwellian
distribution, from the smaller asteroids, which are fitted by a mixture
of Maxwellian distributions. It is found that the optimal separation
occurs at about 32.5 km, and that a mixture of three Maxwellians
comprising slow rotators, fast rotators and a population identical to
the larger asteroids provides the best fit. Copyright 1999, Institute
for Scientific Information Inc.

----------------------------------------
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LETTERS TO THE MODERATOR, 5 March 1999
--------------------------------------

MODERATOR'S NOTE: I am sorry for yesterday's problems with the new
CCNet-ESSAY list. When I set up the new lists, I simply forgot to
inform my university's listserver that they should be *closed* rather
than a free-for-all. The format has now been changed so that all CCNet
lists are now moderated. To unsubscribe from any of the lists, please
contact me with your instructions.

Benny J Peiser


(1) SOME CORRECTIONS
    Paolo Farinella <paolof@keplero.dm.unipi.it> >

(2) IMPORTANT NEWS FROM AUSTRALIA
    Gerrit Verschuur <GVERSCHR@MOCHA.MEMPHIS.EDU>

(3) MUSIC STARS
    Scott Manley <spm@star.arm.ac.uk>

=================
(1) SOME CORRECTIONS

From Paolo Farinella <paolof@keplero.dm.unipi.it> >

Dear Benny,

concerning the March 4 CCNet letters, I will probably be not alone in
remarking that Chairman Sensenbrenner of the Committe on Science of the
U.S. House of Representative is mixing up the major mass extinctions.
The Permo-Triassic one, that he mentions in relation to the dinosaurs'
demise, actually occurred some 150 Myr before that event. I also don't
agree - but this is just an opinion - with the characterization of the
proposed Clementine 2 mission as anti-NEO defense technology.

Some different errors are contained in Bob Kobres's letter on Opik and
the EK-belt objects. I think Bob is aware of the fact that the 13-Myr
average interval found by Levison & Duncan for impact on Earth by
comets from the EK belt is just an average, and does not imply in any
way a periodicity. However, some readers may have misunderstood this
crucial point. Also, the vast majority of these comets would be
km-sized objects, not much larger (Chiron-sized) bodies like those
which are being discovered today in the belt. Finally, the EK-generated
(short-period) comets have been probably formed beyond Neptune, well
outside the Oort cloud comets which are mostly former planetesimals
from the Jupiter zone, ejected after close planetary encounters.
Little is known on the density and composition of both types of comets,
but the argument from the formation site works in reverse.

Best regards,
Paolo Farinella

================
(2) IMPORTANT NEWS FROM AUSTRALIA

From Gerrit Verschuur <GVERSCHR@MOCHA.MEMPHIS.EDU>

FROM A PRESS RELEASE FROM THE ANGLO-AUSTRALIAN OBSERVATORY, IN EPPING,
NEW SOUTH WALES

(A few highlights shown to make a point.)

Southern Cosmic Census creates the largest map of the universe

Astronomers have created the largest map of the Universe using the
Anglo-Australian Telescope, in NSW, Australia and there is much more to
come. The scientists are using the 2dF (Two-degree field) instrument on
the 3.9-metre Anglo-Australian Telescope (the largest optical telescope
in Australia). Researchers are only part way through their work, and
are planning to make the map 10 times as big.
.....
"We have been planning this survey for almost ten years, and as the
results come flooding in our ambitious goals are being fulfilled. At
this rate, we will have no problems completing our survey by 2001."
........
So far the 2dF Galaxy Redshift Survey has pinpointed 30 000 galaxies.
......
The 2dF is one of the most complex astronomical instruments ever
constructed. It took seven years to perfect, and was built in-house at
the Anglo-Australian Observatory.........

COMMENT BY GERRIT VERSCHUUR

While making a map of the universe is a laudable task, I find it ironic
that in Australia they are carrying out such a massive project given
what happened  to their asteroid search program.

The good news is that when the survey is complete we will know which
galaxies pose a hazard to us!

========================
(3) MUSIC STARS

From Scott Manley <spm@star.arm.ac.uk>

Benny,

I don't know if anyone's mentioned it to you but there's a nice 2 page
article in the current issue of 'Q' magazine which lists all the
asteroids named after famous musicians. They interviewed Gareth
Williams and have a nice big picture showing the solar system... except
that even if the asteroids are in the right place then Jupiter, Venus
and Earth are in the wrong place....

And... in my continual quest to keep people interested in my NEO map -
I've now added an AVI movie to the same page showing a year in the life
of the earth as it flies through its 'Cosmic Shooting Gallery' - look
at http://szyzyg.arm.ac.uk/~spm/neo_map.html

Scott Manley (aka Szyzyg)

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