PLEASE NOTE:


*

CCNet 84/2001 - 3 July 2001
---------------------------


"Pluto has suffered another demotion with scientists discovering a
very bright, icy body possibly even larger than the tiny ice-planet's moon
Charon and orbiting the Sun in the same celestial neighborhood."
--Space.com, 2 July 2001


"Dr David Jewitt of the University of Hawaii who has discovered many
KBO's, including the first one ever seen, told BBC News Online: "We're
inching up to Pluto. It is just a matter of time until we see Pluto
2, Pluto 3 and so on." Robert Millis agrees: "Until the Kuiper Belt has
been thoroughly explored, we cannot pretend to know the extent or the
content of the Solar System."
--BBC News Online, 3 July 2001


"Some years ago, Opik and I published a paper on meteorite ejection.
We argued that the escape velocity would require an acceleration, and
force, exceeding the crushing strength of rocks  -- similar to your
argument. Since then I have been persuaded by the evidence put forth by
Heinrich Waenke and others that certain meteorites did originate from the
surface of Mars. The obvious explanation is a slow ejection
mechanism rather than an impulsive one, perhaps driven by gas
erupting from Mars."
--S. Fred Singer, 1 July 2001


"... Also virtually impossible would be a gas-entrainment mechanism
that might increase the time of acceleration because of gradual
expansion following the initial impact. First, there isn't much gas on
Mars, and pressure hardly increases sound speed at all. Extreme
compression would push many gasses past their triple point and in effect
liquify them; this is especially true of the carbon dioxide making up
about 95% of the Martian atmosphere. If we assume optimistically
that the gas was of Earth air composition, its speed of sound at 300
K would be about 330 m/s. The speed of sound in an ideal gas varies about as
the square root of temperature (v oc sqrt(k*T/m). To accelerate a rock
to 5 km/s, remembering that the temperature of a gas drops proportional
to its expansion rate, we would need the gas in a tightly-fitting,
gun-barrel-like cylinder expanding at something like 20 times its speed
of sound at 300 K; this would require a temperature of some 400*300 =
120,000 K. The temperature of the Sun's photosphere being only some 5,500
K, this would seem highly unlikely in a mere asteroid impact..."
--John Michael Williams, 2 July 2001


(1) KUIPER BELT OBJECT FOUND POSSIBLY AS LARGE AS PLUTO'S MOON
    CERRO TOLOLO INTER-AMERICAN OBSERVATORY, 2 June 2001

(2) PLUTO SUFFERS ANOTHER DEMOTION: BIG MOON-SIZED OBJECT FOUND BEYOND
NEPTUNE
    Space.com, 2 June 2001

(3) INCHING UP TO PLUTO AS ANOTHER LARGE KUIPER BELT OBJECT IS FOUND
    BBC News Online, 3 July 2001

(4) DUST DEVILS RESHAPE MARS
    Space.com, 2 June 2001

(5) COMETS II: SPACE SCIENCE SERIES ANNOUNCEMENT
    Richard P. Binzel <rpb@MIT.EDU>

(6) EJECTION OF MARTIAN ROCKS
    S. Fred Singer <singer@sepp.org>

(7) EJECTION OF MARTIAN ROCKS I
    John Michael Williams <jwill@AstraGate.net>

(8) THE UNLIKELY PHYSICS OF THE SUPPOSED METEORITES FROM MARS
    http://publish.aps.org/eprint/gateway/eplist/aps1999jun25_002

(9) EJECTION OF MARTIAN ROCKS II
    John Michael Williams <jwill@AstraGate.net>

(10) TANNER ON TR/J EXTINCTIONS
     Hermann Burchard <burchar@mail.math.okstate.edu>


=========
(1) KUIPER BELT OBJECT FOUND POSSIBLY AS LARGE AS PLUTO'S MOON

From CERRO TOLOLO INTER-AMERICAN OBSERVATORY, 2 June 2001
http://www.ctio.noao.edu/news/kuiperobj.html

July 2, 2001

RELEASE: NOAO 01-10

Astronomers from Lowell Observatory, the Massachusetts Institute of
Technology, and the Large Binocular Telescope Observatory have discovered an
icy planetary body orbiting the Sun beyond Neptune in the Kuiper Belt
roughly equal in size to Pluto's moon Charon.

"This object is intrinsically the brightest Kuiper Belt Object found so
far," says Lowell Observatory Director Robert Millis, leader of the survey
team. "The exact diameter of 2001 KX76 depends on assumptions that
astronomers make about how its brightness relates to its size. Traditional
assumptions make it the biggest by a significant amount, while others make
it larger by at least 5 percent."

Assuming a reflectivity (or albedo) of 4 percent, 2001 KX76 would have a
diameter of approximately 1,270 kilometers (788 miles), bigger than Ceres,
the largest known asteroid. For comparison, Pluto's moon Charon has an
estimated diameter of 1,200 kilometers (744 miles).

Earlier this year, a Kuiper Belt Object (KBO) called 20000 Varuna was
announced with an estimated diameter of 900 kilometers, based on a
calculated reflectivity of 7 percent. Applying this albedo to 2001 KX76
gives it a diameter of roughly 960 kilometers (595 miles).

2001 KX76 was discovered in the course of the Deep Ecliptic Survey, a
NASA-funded search for KBOs being conducted by the Lowell-MIT-LBT team using
the National Science Foundation's telescopes at Kitt Peak National
Observatory near Tucson, AZ, and Cerro Tololo Inter-American Observatory in
Chile. The team spotted 2001 KX76 in deep digital images of the southern sky
taken with the 4-meter Blanco Telescope at Cerro Tololo on May 22 by James
L. Elliot of MIT and Lawrence H. Wasserman of Lowell Observatory.

2001 KX76 is currently at a distance of just over 6.4 billion kilometers (4
billion miles) from the Sun. Its orbit is inclined by approximately 20
degrees with respect to the orbital plane of the major planets, but the
detailed shape of its orbit remains uncertain. Available evidence suggests
that the newly discovered KBO may be in an orbital resonance with Neptune,
orbiting the Sun three times for each time that Neptune completes four
orbits.

The brightness and colors of 2001 KX76 have been measured by Elliot, Susan
Kern, and David Osip, all of MIT, with the Raymond and Beverly Sackler
Magellan Instant Camera (MagIC) on the 6.5-meter Magellan Telescope at Las
Campanas Observatory in Chile. The object has a distinctly reddish color
typical of many primitive bodies in the outer Solar System.

"2001 KX76 is so exciting because it demonstrates that significant bodies
remain to be discovered in the Kuiper Belt," Millis explains. "We have every
reason to believe that objects ranging up to planets as large or larger than
Pluto are out there waiting to be found. Until the Kuiper Belt has been
thoroughly explored, we cannot pretend to know the extent or the content of
the Solar System."

The existence of the Kuiper Belt was postulated by J. A. Fernandez and by M.
Duncan, T. Quinn, and S. Tremaine in the 1980s to explain the origin of
short-period comets. These comets move around the Sun in the same direction
as the planets, and are found in orbits that are tipped only modestly with
respect to the ecliptic plane. These researchers showed that short-period
comets could not have originated from the more distant spherical Oort Comet
Cloud as originally believed. They predicted that a second, more flattened
reservoir of "proto-comets" must lie beyond the orbit of Neptune.

The first Kuiper Belt Object was found in 1992 by David Jewitt and Jane Luu
of the University of Hawaii. Since then, astronomers have found over 400
KBOs, but tens of thousands likely remain to be discovered. These objects
are believed to be remnants from the formation of the Solar System, and
consequently are among the most primitive and least-evolved objects
available for study by planetary astronomers.

About one-quarter of the known KBOs have been found by the Deep Ecliptic
Survey Team. Other members of the team are Marc Buie of Lowell and Mark
Wagner of the Large Binocular Telescope Observatory on Mount Graham, AZ. The
Deep Ecliptic Survey was recently awarded formal survey status at the
National Optical Astronomy Observatory (NOAO), assuring that this
reconnaissance of the outer Solar System will continue for the next three
years.

Much more precise measurement of KBO diameters will be possible with NASA's
upcoming Space Infrared Telescope Facility (SIRTF) mission, due for launch
in 2002.

Kitt Peak and Cerro Tololo Inter-American Observatory are part of NOAO,
which is operated by the Association of Universities for Research in
Astronomy (AURA), Inc., under a cooperative agreement with the National
Science Foundation.

The survey team's research is supported by the NASA Planetary Astronomy
Program through grants to Lowell Observatory, Flagstaff, AZ, and MIT in
Cambridge, MA.

========
(2) PLUTO SUFFERS ANOTHER DEMOTION: BIG MOON-SIZED OBJECT FOUND BEYOND
NEPTUNE

From Space.com, 2 June 2001
http://www.space.com/scienceastronomy/solarsystem/big_kuiper_object_010702.html

By SPACE.com Staff

Pluto has suffered another demotion with scientists discovering a very
bright, icy body possibly even larger than the tiny ice-planet's moon Charon
and orbiting the Sun in the same celestial neighborhood.

The object, called 2001 KX76, orbits beyond Neptune in the Kuiper Belt of
early solar system ice-and-rock smidgeons.

"This object is intrinsically the brightest Kuiper Belt Object found so
far," says Lowell Observatory Director Robert Millis, leader of the survey
team. And brightness is how astronomers calculate size.

Under one assumption about the object's reflectivity (albedo), 2001 KX76 is
probably 788 miles (1,270 kilometers), making it 44 miles larger across than
Charon and even bigger than Ceres, the largest known asteroid.

"2001 KX76 is so exciting because it demonstrates that significant bodies
remain to be discovered in the Kuiper Belt," Millis said.

"We have every reason to believe that objects ranging up to planets as large
or larger than Pluto are out there waiting to be found. Until the Kuiper
Belt has been thoroughly explored, we cannot pretend to know the extent or
the content of the Solar System."

Varuna verity

The truth is that 2001 KX76 could be a bit smaller than Charon. It all
depends on how reflective such objects are.

For instance, earlier this year, a Kuiper Belt Object (KBO) called 20000
Varuna was announced with an estimated diameter of 558 miles (900
kilometers), based on a calculated reflectivity of 7 percent.

Applying this albedo to 2001 KX76 gives it a diameter of only 595 miles (960
kilometers).

Reddish and resonant

2001 KX76 was discovered in the course of the Deep Ecliptic Survey, a
NASA-funded search for KBOs.

The team spotted 2001 KX76 in deep digital images of the southern sky taken
with the 4-meter Blanco Telescope at Cerro Tololo on May 22 by James L.
Elliot of the Massachusetts Institute of Technology (MIT) and Lawrence H.
Wasserman of Lowell Observatory.

2001 KX76 currently is just over 4 billion miles (6.4 billion kilometers)
from the Sun. Its orbit is inclined by approximately 20 degrees with respect
to the orbital plane of the major planets, but the detailed shape of its
orbit remains uncertain.

Available evidence suggests that the newly discovered KBO may be in an
orbital resonance with Neptune, orbiting the Sun three times for each time
that Neptune completes four orbits.

The object has a distinctly reddish color typical of many primitive bodies
in the outer Solar System.

KBOs

The existence of the Kuiper Belt was postulated by J. A. Fernandez and by M.
Duncan, T. Quinn, and S. Tremaine in the 1980s to explain the origin of
short-period comets.

These comets move around the Sun in the same direction as the planets and
are found in orbits that are tipped only modestly with respect to the
ecliptic plane.

These researchers showed that short-period comets could not have originated
from the more distant spherical Oort Comet Cloud as originally believed.
They predicted that a second, more flattened reservoir of "proto-comets"
must lie beyond the orbit of Neptune.

The first Kuiper Belt Object was found in 1992 by David Jewitt and Jane Luu
of the University of Hawaii. Since then, astronomers have found over 400
KBOs, but tens of thousands likely remain to be discovered.

These objects are believed to be remnants from the formation of the Solar
System, and consequently are among the most primitive and least-evolved
objects available for study by planetary astronomers.

The Deep Ecliptic Survey

About one-quarter of the known KBOs have been found by the Deep Ecliptic
Survey Team.

Much more precise measurement of KBO diameters will be possible with NASA's
upcoming Space Infrared Telescope Facility (SIRTF) mission, due for launch
in 2002.

The survey team's research is supported by the NASA Planetary Astronomy
Program through grants to Lowell Observatory and MIT. The team includes
astronomers from Lowell Observatory, MIT and the Large Binocular Telescope
Observatory.

Copyright 2001, Space.com

========
(3) INCHING UP TO PLUTO ANOTHER LARGE KUIPER BELT OBJECT IS FOUND

From the BBC News Online, 3 July 2001
http://news.bbc.co.uk/hi/english/sci/tech/newsid_1419000/1419508.stm

By BBC News Online science editor Dr David Whitehouse

Astronomers have found one of the largest objects ever detected orbiting the
Sun.

It was seen in a deep space survey looking for bodies circling the Sun out
near Pluto, the most distant planet. Only planets are larger than the new
object, dubbed 2001 KX76.

The icy, reddish world is over a thousand kilometres in size and astronomers
say there may be even larger ones, bigger than planet Pluto itself, awaiting
discovery.

"What we have seen may be only the tip of the iceberg," co-discoverer Dr
Lawrence Wasserman told BBC News Online.

When we spotted it we just wrote 'wow' on the image, we knew right away it
was a big one
 
Lawrence Wasserman Lowell Observatory 

The world, for it is big enough to be called a world, has a typical reddish
hue and is probably covered in ice. It orbits the Sun beyond Neptune in the
so-called Kuiper Belt - a region that extends far beyond the known planets.

Since 1992, over 400 Kuiper Belt Objects (KBOs) have been detected. Their
discovery has revolutionised our view of the distant reaches of our solar
system.

It is the sheer size of 2001 KX76 that is exciting astronomers.

"When we spotted it we just wrote 'wow' on the image, we knew right away it
was a big one," Lawrence Wasserman, of the Lowell Observatory in Arizona,
told BBC News Online.

"This object is intrinsically the brightest Kuiper Belt Object found so
far," says Lowell Observatory Director Robert Millis.

"The exact diameter of 2001 KX76 depends on assumptions that astronomers
make about how its brightness relates to its size. Traditional assumptions
make it the biggest by a significant amount, while others make it larger by
at least 5%," he added.

2001 KX76 could be as large as 1270 km (788 miles), bigger than Ceres, the
largest known asteroid - an object that orbits the Sun between Mars and
Jupiter.

It is even larger than Pluto's moon Charon which has an estimated diameter
of 1200 km (744 miles).

Uncertain orbit

2001 KX76 was discovered in the course of the Deep Ecliptic Survey, a
Nasa-funded search for KBOs.

It was seen on 22 May in deep digital images of the southern sky taken with
the 4-metre Blanco Telescope at Cerro Tololo in Chile.

Astronomers estimate that 2001 KX76 is currently at a distance of just over
6.4 billion km (4 billion miles) from the Sun. Its orbit is inclined by
approximately 20 degrees with respect to the major planets, but the detailed
shape of its orbit remains uncertain.

Available evidence suggests that the newly discovered KBO may be in an
orbital dance with Neptune, orbiting the Sun three times for each time that
Neptune completes four orbits.

"2001 KX76 is so exciting because it demonstrates that significant bodies
remain to be discovered in the Kuiper Belt," Robert Millis explains.

Lawrence Wasserman agrees: "We have every reason to believe that objects
ranging up to planets as large or larger than Pluto are out there waiting to
be found."

Dr David Jewitt of the University of Hawaii who has discovered many KBO's,
including the first one ever seen, told BBC News Online: "We're inching up
to Pluto. It is just a matter of time until we see Pluto 2, Pluto 3 and so
on."

Robert Millis agrees: "Until the Kuiper Belt has been thoroughly explored,
we cannot pretend to know the extent or the content of the Solar System."

The researchers hope that other astronomers who have access to large
telescopes over the next few weeks will be able to turn them on 2001 KX76 in
the hope of gathering enough light to get a spectrum of the object.

Copyright 2001, BBC

========
(4) DUST DEVILS RESHAPE MARS

From Space.com, 2 June 2001
http://www.space.com/scienceastronomy/solarsystem/dust_edgett_010702-1.html

By Jet Propulsion Laboratory

NASA's Mars Global Surveyor spacecraft recently caught sight of a dust devil
dancing across the Martian surface. While it isn't the first of the
tornado-like weather systems to be imaged, it is yet another reminder that
Mars is an ever-changing planet.

Dr. Ken Edgett, a staff scientist at Malin Space Science Systems in San
Diego, Calif., regularly tracks the dust devils and studies surface
features. As the operator for the Surveyor's orbiter camera, he is one of
the first to see fascinating images of the red planet. Dr. Edgett recently
discussed the importance of dust devils and how they are transforming the
look of Mars.

Q: First of all, what is a dust devil?

On Mars, Hurricane Andrew would stick in the memory as a gentle breeze. And
the oppressive heat and biting sandstorms of the Mojave? Hang on to your
cosmic hats, because the wildest, wackiest and worst weather known does not
occur on Earth. Click here to find out which planets have the scariest
forecasts.

A: A dust devil is something that happens both on Earth and on Mars and
looks somewhat like a mini-tornado. As with tornadoes, dust devils are
spinning columns of air. Such a column is called a vortex--you might see the
same effect when you let water run down a bathtub drain. Unlike tornadoes,
dust devils aren't usually associated with storms. You typically see them on
dry, sunny summer days when there is anywhere from a little to no breeze.
You might say they look something like that Tasmanian Devil cartoon
character - he spins 'round and 'round like a tornado when he moves.

A dust devil is actually a visual apparition of a wind vortex. If there
isn't any dust on the ground, a vortex might still form but no one would see
it. An example of a vortex without dust might be the scene in the film
American Beauty where the plastic shopping bag is caught on videotape,
spinning, spiraling, and dancing in the air. Dust devil vortices form when
the air is fairly calm and the ground is heated by sunlight-this heats the
air immediately above ground. Hot air rises up the outside of the spinning
column, while cooler air descends through its middle. If a vortex passes
over a dusty surface, it will pick up the dust and become a visible feature
-- a dust devil.

Q: Are Martian dust devils different than devils on Earth?

A: The Martian surface is so much more dusty than Earth because here we have
rain to wash away most of the dust that settles out of the sky, but on Mars
it doesn't rain. What's neat about the Martian dust devils is that they
create "art". All that extra dust on the ground means that the dust devils
leave tracks behind them where they have either picked up dust or disturbed
the dust lying about on the surface. Most of the time these tracks are
darker than the surroundings, but sometimes they are lighter---it just
depends upon whether the surface under the thin coating of dust is brighter
or darker than the dust itself. In some places on Mars, you can get hundreds
of crisscrossing dust devil tracks, they make a pattern that some say
resembles Jackson Pollack paintings, others say resembles something their
2-year old might do with crayons.

Q: How do you detect dust devils in the Global Surveyor data?

A: NASA's Mars Global Surveyor spacecraft has the Mars orbiter camera,
that's actually three-cameras-in-one.

The two wide-angle cameras are used every day to take a global portrait of
Mars; we use these to document changes in weather and frost patterns. The
high-resolution camera, on the other hand, is used to see things up close.
Its main purpose is to examine the geology and geomorphology---the shape of
the landforms. Every once in a while, however, one of these cameras captures
a dust devil in action. The high-resolution camera has a very narrow field
of view---we can only see areas about 3 kilometers (1.9 miles) across, so no
one really expected we'd ever see a dust devil with this camera. But we
have.

More amazing to us, sometimes the dust devils are so big that you can see
them with the wide-angle cameras meaning that they are wide enough to cover
a couple football fields and stand several kilometers high.

Q: Did you know dust devils existed before Global Surveyor?

A: Vortices, though no one knows if they had dust in them or not, were
detected by the meteorology experiments on the two Viking landers in the
late 1970s. Similar detections occurred during the 1997 Mars Pathfinder
mission. Some of these went right over the lander without causing damage. In
the mid-1980s, researchers at Cornell University realized that some of the
Viking pictures taken from orbit showed dust devils---from orbit what you
see is usually a round, fuzzy-looking cloud that is casting a very long,
columnar shadow. Researchers at the University of Nevada in Reno have
suggested that a few of Mars Pathfinder's images also detected dust
devils---these appear as actual columns of dust moving across the distant
landscape.

When Mars Global Surveyor arrived in late 1997, we started seeing in our
high-resolution pictures, thin narrow tracks running across the surface in
some places, especially in the dust-covered areas. We suspected these were
caused by dust devils, but we had no proof. Later on we were able to
photograph some of these tracks a second time, and lo and behold, they had
changed! In some cases there were more tracks, in others the original tracks
had completely disappeared and were replaced by new ones, like some giant
Martian Etch-a-sketch. "There can't be that many dust devils on Mars, can
there?" we wondered. But indeed it's true that in some areas out in the
deserts of Arizona and Nevada, people have recorded hundreds of dust devils
over periods of only a few weeks. So you can have lots of dust devils, it
happens on Earth.

In December of 1999, we got our first really good image that actually caught
a dust devil in the act of creating one of these dark streaks. We were
thrilled! After that, we've now seen dozens of cases where dust devils are
creating streaks--usually dark streaks, but in early April 2001 we got one
in Amazonis Planitia that was making a very faint bright streak.

Q: Speaking about that dust devil image in Amazonis Planitia, what was it
like when you first saw that image?

A: I was tickled. It is always neat to see these dust devils in Global
Surveyor images. We don't get them every day, so when we spot them they
always create a buzz among the camera operations staff -- "come see what I
found!" This particular dust devil from April was exciting because it isn't
a round, fuzzy cloud. It's a twisted thing that casts a dark, bent shadow.
Because the camera is looking straight down, the shadow is what gives the
best impression of the shape of the thing. Bent dust devils like this aren't
unusual, but neat nonetheless. The bending is caused by differences in the
wind at different levels in the lower Martian atmosphere at the time the
dust devil was moving across the landscape.

Q: If that same dust devil appeared on Earth would it do any damage?

A: This particular dust devil probably wouldn't cause any real damage,
though in the April image it was clearly picking up dust and creating a
faint, bright streak. If you went and stood in the way and the dust devil
came over you, you'd certainly feel it, though. I once drove my car into a
dust devil down along I-8 near Yuma, Arizona, and it definitely jiggled the
car around. Do not try this at home! I should say, however, that there are
documented cases on Earth where dust devils, as opposed to tornadoes, have
caused some damage, including buildings, but usually this is not the case.
Some stronger dust devils can have winds comparable to small tornadoes.

Q: Why do you study dust devils?

A: Dust devils are one of the mechanisms by which dust is moved around and
redistributed on Mars. They are part of a process that is active today,
meaning that Mars is not a "dead" planet but has things that are happening
right now. Dust devils may contribute some of that dust that gives the sky
its pinkish color. Dust devils also appear to play a role in cleaning off
dark surfaces. For hundreds of years, people saw in telescopes that Mars'
surface markings would change over the course of a year. In spring, areas
would get darker and then get lighter in autumn. Once upon a time, it was
thought that the "wave of darkening" was caused by springtime growth of
vegetation. We now know that blowing dust is what causes these changes, and
with Mars Global Surveyor's high-resolution images, it now appears that some
areas darken because dust devils come along in the spring and summer months
to clean dust off that accumulated in autumn and winter or, at least, that's
what I think we're seeing with this camera.

Q: Do you have a favorite dust devil image?

A: Yes, it was taken October 14, 1999, in the western Daedalia Planum
region. I just happen to like this one because it is very dramatic, though
it is not creating a streak on the surface--they don't all make streaks.
When it first came in, I was really moved by the experience of seeing an
event that had taken place on Mars just a few hours earlier.

Q: What is it about dust devils that surprise you?

A: The fact that we can catch them in action! We see such a limited amount
of the surface with the high-resolution camera, to date we've photographed
less than 2 percent of the surface, yet we have seen dozens of dust devils
and thousands of streaks that we think are produced by them. This must mean
that dust devils are very common all over Mars. It surprises me that we even
see their streaks at the top of the giant volcano, Olympus Mons, where the
atmosphere is so thin---about 10 times thinner than at the Mars Pathfinder
site--that you are almost in a vacuum. When you get lucky and catch a dust
devil in one of these images, you get an eerie chill down your spine. These
are dynamic things and you just happened to catch one at the time the
spacecraft flew overhead. Dust devils give me a chill when I see them out in
nature on Earth--they often seem to have a mind of their own. They might
come toward you, then go away from you, as if teasing you. To see these on
Mars gives me that same sense of being tantalized and teased. The dust devil
you capture today is something that will not be there tomorrow.

Copyright 2001, Space.com

============
(5) COMETS II: SPACE SCIENCE SERIES ANNOUNCEMENT

From Richard P. Binzel <rpb@MIT.EDU>

Dear Colleague,

The Space Science Series is pleased to announce plans for a new upcoming
volume: COMETS II
edited by Michel Festou, Uwe Keller, Harold Weaver and planned for
publication by the University of Arizona Press in 2003.

The process of forming the Scientific Organizing Committee (SOC) for the
book COMETS II is now underway and persons interested in devoting
substantial effort as a member of the book SOC are invited to contact the
lead editor:

Michel Festou (festou@ast.obs-mip.fr).

A second announcement will be made soon to solicit community-wide ideas and
volunteers for chapters for COMETS II.

The principal scientific meeting bringing together authors for COMETS II
will be the Asteroids Comets Meteors (ACM2002) conference  to be held in
Berlin from July 29 to August 2, 2002. Participation in the book does not
require participation or attendance at the ACM2002 conference.  Information
on the conference is available at the web site:
           http://earn.dlr.de/ACM2002

Chapters for COMETS II will be due promptly after the ACM2002 meeting.

A more immediate opportunity for authors and participants of the COMETS II
book to meet and plan their work is the "5 Years After Hale Bopp" conference
to be held in Tenerife January 21-25, 2002. Information on this conference
is available at the web site:          http://r2d2.stcloudstate.edu/

Broad and active participation by the international planetary science
community in making COMETS II a success is essential and most certainly
welcomed and encouraged!

Sincerely,

Richard P. Binzel,
General Editor
Space Science Series

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

(6) EJECTION OF MARTIAN ROCKS

From S. Fred Singer <singer@sepp.org>

Re: CCNet 79/2001 - 18 June 2001

Some years ago, Opik and I published a paper on meteorite ejection. We
argued that the escape velocity would require an acceleration, and force,
exceeding the crushing strength of rocks  -- similar to your argument.

Since then I have been persuaded by the evidence put forth by Heinrich
Waenke and others that certain meteorites did originate from the surface of
Mars. The obvious explanation is a slow ejection mechanism rather than an
impulsive one, perhaps driven by gas erupting from Mars.

I have not seen any calculations along these lines.

Best,                 Fred

S. Fred Singer, President
Science & Environmental Policy Project
http://www.sepp.org

===========
(7) EJECTION OF MARTIAN ROCKS I

From John Michael Williams <jwill@AstraGate.net>

Hello Fred.

You should read my paper at
http://publish.aps.org/eprint/gateway/eplist/aps1999jun25_002

Gas ejection would be highly unlikely, as discussed in the "cartoon" text at
the end of the paper. The speed of sound in gas by definition equals the
speed of expansion of that gas into vacuum. Any gas, even hydrogen, at less
than astrophysical temperatures, would therefore be able to push something
entrained with it to at most something like 2 or 3 km/s. 

I agree that gas would allow entrained material to be accelerated intact . .
. exactly because the speed of sound in any gas is below that of almost any
rock.

The problem is not obviously crushing strength, but rather rate of
propagation of energy.   Young's modulus and other parameters would be
shared in quantizing sound speed as well as crushing strength, but the two
ideas actually are independent.

                         John
                     jwill@AstraGate.net
                     John Michael Williams

------------
(8) THE UNLIKELY PHYSICS OF THE SUPPOSED METEORITES FROM MARS

http://publish.aps.org/eprint/gateway/eplist/aps1999jun25_002
By: John Michael Williams (jwill@AstraGate.net)

Several rocks recovered from Antarctica and a few other Earth locations have
been identified as meteorites supposed to have been ejected from the planet
Mars in the geologically recent past. Much previous discussion of these
rocks has been directed at the possible mechanism of ejection, but little
has been written about the basic physics of the effects of such ejection on
rock. We show here that no kind of rock known on Earth likely could have
been ejected at or above the Martian escape speed by an impact, no matter
what the mechanism. (28 pages)

=========
(9) EJECTION OF MARTIAN ROCKS II

From John Michael Williams <jwill@AstraGate.net>

Hello Fred.

Concerning the possibility of gentle, gaseous acceleration of an impact
ejectum, here's an extract of some of the revised ms I have been preparing (I have yet to
complete some of the basic speed-of-sound derivations):

"... Also virtually impossible would be a gas-entrainment mechanism
that might increase the time of acceleration because of gradual
expansion following the initial impact.  
 
First, there isn't much gas on Mars, and  pressure hardly increases
sound speed at all.   Extreme compression would push many gasses past
their triple point and in effect liquify them; this is especially
true of the carbon dioxide making up about 95% of the Martian atmosphere.

 
If we assume optimistically that the gas was of Earth air
composition, its speed of sound at 300 K would be about 330 m/s. The
speed of sound in an ideal gas varies about as the square root of
temperature (v oc sqrt(k*T/m) ). To accelerate a rock to 5 km/s, remembering
that the temperature of a gas drops proportional to its expansion rate, we
would need the gas in a tightly-fitting, gun-barrel-like cylinder expanding
at something like 20 times its speed of sound at 300 K; this would require
a temperature of some 400*300 = 120,000 K. The temperature of the Sun's
photosphere being only some 5,500 K, this would seem highly unlikely in
a mere asteroid impact..."

==============
(10) TANNER ON TR/J EXTINCTIONS

From Hermann Burchard <burchar@mail.math.okstate.edu>

Dear Benny,

at the GSL/GSA conference in Edinburgh last week, as communicated to CCNet
June 29 by Andrew Yee, some remarkable empirical observations were reported
by Larry Tanner giving proof that CAMP basalt eruptions did not release
sufficient amounts of CO2 to have caused the Tr/J extinctions:

Ann Cairns, Director-Communications
GSA Release No. 01-27
Mass Extinction At The Triassic-Jurassic Boundary: Where's The
Smoking Gun?  ....
"The mass extinction that marks the end of the Triassic is one of
the five largest extinction events of the Phanerozoic Eon.."  ...
Tanner will address possible explanations for this event.  ... "Then
there's asteroid impact -- however, no impact structure can be
tied directly to the Triassic-Jurassic boundary. .." ... no evidence
for any change in the CO2 composition of the atmosphere.

In this connection, very precise dates near 200 Ma were obtained for the
Tr/J boundary recently:

  * Queen Charlotte Islands, British Columbia, Tr/J radiolarian plancton
    extinction strata, the age of 199.6 Ma was given by Peter Ward et al.
  * Brazilian CAMP basalts, 199.02.4 Ma mean 40Ar/39Ar age was given
    by Angelo De Min, Paul Renne, et al.

But, Larry Tanner's statement that "no impact structure can be tied directly
to the Triassic-Jurassic boundary" may not be strictly correct. He is
referring (see the abstract) to the Manicougan crater in Quebec being dated
at 214 Ma, which is too early, etc.

However, his statement ignores that structures other than craters have been
tagged by geologists for impact causation, see list below.  Here, we suggest
specific Tr/J-related instances of such structures, which are possibly
caused by cosmogenic impact at the 200 Ma epoch:

  * Azores mantle hotspot / plume located near the center of the CAMP
  * CAMP basalts in Europe, Africa, N & S America dated to 200 Ma
  * North Atlantic Rift / Mid Ocean Ridge began with CAMP eruptions
  * SSE of Azores hotspot track Atlantis, Cruiser, Great Meteor seamounts

There are plenty possible and prominent impact structures available here.
One may accept these as being impact structures or not, depending on one's
preference of current geological theory. And who knows, a crater may yet be
found, buried under CAMP basalts on four continents.

Regards,
Hermann

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