PLEASE NOTE:


*

CCNet 83/2001 - 29 June 2001
----------------------------


"Who did it? Who pulled the trigger, or rather, what pulled the
trigger at the Triassic- Jurassic boundary that wiped out 20% of all
marine families in Earth's oceans, and, on land, most non-dinosaurian
archosaurs, most therapsids, and the last of the large amphibians? [...]
The current favorite hypothesis is that flood basalts that constitute the
Central Atlantic Magmatic Province erupted. And the release of CO2 or SO2
aerosols during these eruptions are thought to have caused intense
global warming (from the former) or cooling (from the latter). But
Tanner's new data on the isotopic composition of fossil soils of
Late Triassic and Early Jurassic age demonstrates that there is no evidence
of any change in the CO2 composition of the atmosphere. So the smoking gun
still eludes scientists and the cause of this extinction is still at
large. "Other possibilities need to be investigated more fully," Tanner
explained."
--Ann Cairns, Director-Communications, Geological Society of
America


"We speculate that it may also have perturbed asteroids in the inner
part of the asteroid belt, throwing one or more of them into
Earth-crossing orbits," explained Bruce Runnegar, Director of UCLA's
Center for Astrobiology. "Thus, the ultimate cause of the K-T impact --
and demise of the dinosaurs -- may have been a chaos-induced change in Solar
System dynamics."
--Press Release, Geological Society of America, 21 June 2001


"This is the kind of idle speculation hyping the press that is not
worth repeating. The chaotic change of terrestrial planet orbits 65 my
ago may or may not be verifiable, but the speculation that it
triggered an "asteroid shower" analogous to putative "comet showers" can
be shot down in a couple lines. Proposed "comet showers" have a decay time
of around 10 my, because the planet crossing comets are cleaned out, not
by the terrestrial planets, but by the giant planets, which are much
more efficient at sweeping out stuff crossing their orbits. Not so for
NEAs that do not cross the giant planet orbits. The clearing out time for
NEAs is much longer, of order 100 MY.  The characteristic time of an earth
impact is even longer, of order 300 MY for a single object." 
--Alan W. Harris, Jet Propulsion Laboratory


(1) NEO HAZARD MITIGATION PUBLICATION ANALYSIS AVAILABLE ONLINE
    Christian Gritzner <christian.gritzner@mailbox.tu-dresden.de>

(2) NAKED-EYE COMET
    SpaceWeather.com <spaceweather@lists.spaceweather.com>

(3) MASS EXTINCTION AT THE TRIASSIC-JURASSIC BOUNDARY: WHERE'S THE SMOKING
GUN?
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(4) A DISTURBANCE IN THE "FORCE" CAUSED THE K-T IMPACT?
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(5) ERRATIC PLANETS OR ERRATIC COMPUTER MODELS? SOLAR SYSTEM CHAOS BLAMED
FOR K/T MASS EXTINCTION
    BBC News Online, 27 June 2001

(6) A COMMENT BY ALAN W HARRIS ON MPML
    Alan W. Harris <awharris@lithos.jpl.nasa.gov>

(7) SNOWBALL FIGHT IN EDINBURGH
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(8) VENUS ANALOGUE OF CATASTOPHIC MANTLE OVERTURNS ON PRECAMBRIAN EARTH
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(9) THERE MAY BE SUBGLACIAL VOLCANOES (AND LIFE) ON MARS - MAY BE NOT
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(10) WHERE THERE'S SOUP, THERE'S LIFE
     Andrew Yee <ayee@nova.astro.utoronto.ca>

(11) THE GOLDILOCKS EFFECT: HOW OTHER EARTHS FORM JUST RIGHT
     Andrew Yee <ayee@nova.astro.utoronto.ca>

(12) AND FINALLY: PRIVATE ROCKET LAUNCH IS 'SUICIDAL'
     BBC News Online, 26 June 2001

======
(1) NEO HAZARD MITIGATION PUBLICATION ANALYSIS AVAILABLE ONLINE

From Christian Gritzner <christian.gritzner@mailbox.tu-dresden.de>

Dear Benny,

I would like to inform the CCNet readers that the English summary and report
(pdf-files) of the ESA study on NEO mitigation publications mentioned some
time ago are now available from our homepage:

Gritzner, Ch.,  NEO-MIPA - Near-Earth Object - Hazard Mitigation Publication
Analysis
http://www.tu-dresden.de/mw/ilr/space/space.htm (go to: "Forschung", and
"Publikationen")

Best wishes,
Christian
--
Dresden University of Technology
Institute for Aerospace Engineering
Dr.-Ing. Christian Gritzner, Senior Engineer
D-01062 Dresden, Germany
phone: +49-351-463-8234 (Fax: -8126)
E-mail: christian.gritzner@mailbox.tu-dresden.de
Homepage: http://www.tu-dresden.de/mw/ilr/space/space.htm

==========
(2) NAKED-EYE COMET

From SpaceWeather.com <spaceweather@lists.spaceweather.com>

Space Weather News for June 28, 2001
http://www.spaceweather.com

NAKED-EYE COMET: Comet C/2001 A2 (better known as "Comet LINEAR") makes its
closest approach to Earth on Saturday, June 30th.  Glowing at visual
magnitude 4, Comet LINEAR is not spectacular like, e.g., Comet Hale-Bopp of
1997, but it will be easy to spot with the unaided eye. Astronomers have
watched this comet intently in recent months as it repeatedly crumbled and
brightened.  The capricious snowball from the outer solar system could yet
hold surprises for observers in the days and weeks ahead.  Visit
SpaceWeather.com for finder charts and more information.

ASTEROID MOVIE:  Near-Earth Asteroid 2001 ME1 will glide past Earth on
Friday, June 29th, 38 times farther from our planet than the Moon. Earlier
this week astronomer John Rogers captured a beautiful video of the incoming
space rock gliding among the stars.  See it at SpaceWeather.com.

=============
(3) MASS EXTINCTION AT THE TRIASSIC-JURASSIC BOUNDARY: WHERE'S THE SMOKING
GUN?

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

Geological Society of America
Boulder, Colorado

Contact:
Ann Cairns, Director-Communications
acairns@geosociety.org, 303-447-2020, ext. 1156

June 21, 2001

GSA Release No. 01-27

Mass Extinction At The Triassic-Jurassic Boundary: Where's The Smoking Gun?

Who did it? Who pulled the trigger, or rather, what pulled the trigger at
the Triassic-Jurassic boundary that wiped out 20% of all marine families in
Earth's oceans, and, on land, most non-dinosaurian archosaurs, most
therapsids, and the last of the large amphibians? Whatever it was, it shot
down much of the competition so dinosaurs could later dominate the Earth.

"The Triassic-Jurassic boundary extinction event is one of the 'big five'
mass extinctions of the Phanerozoic Eon, profoundly affecting life on land
and in the oceans," explained Lawrence Tanner, a Professor of Geography and
Geoscience at Bloomsburg University in Pennsylvania. Tanner will shed light
on the various extinction theories on Wednesday, June 27, at the "Earth
System Processes" meeting in Edinburgh Scotland.

"Ultimately, this presentation concerns our ability to test various
hypotheses for the cause of large-scale extinction events of the past," he
said. Tanner will address possible explanations for this event. One is
gradual climate change or sea-level change during the Late Triassic, but
these explanations fail to explain the suddenness of the extinctions in the
marine realm. Then there's; asteroid impact -- however, no impact structure
can be tied directly to the Triassic-Jurassic boundary. And the current
favorite hypothesis is that flood basalts that constitute the Central
Atlantic Magmatic Province erupted. And the release of CO2 or SO2 aerosols
during these eruptions are thought to have caused intense global warming
(from the former) or cooling (from the latter). But Tanner's new data on the
isotopic composition of fossil soils of Late Triassic and Early Jurassic age
demonstrates that there is no evidence of any change in the CO2 composition
of the atmosphere. So the smoking gun still eludes scientists and the cause
of this extinction is still at large. "Other possibilities need to be
investigated more fully," Tanner explained.

The Geological Society of America and the Geological Society of London will
co-convene the Earth Systems Processes meeting in Edinburgh, Scotland.

CONTACT INFORMATION

During the Earth System Processes meeting, June 25-28, contact the GSA/GSL
Newsroom at the Edinburgh International Conference Centre for assistance and
to arrange for interviews: +44 (0) 131 519 4134

Ted Nield, GSL Science and Communications Officer
Ann Cairns, GSA Director of Communications

The abstract for this presentation is available at:
     http://gsa.confex.com/gsa/2001ESP/finalprogram/abstract_7665.htm

Post-meeting contact information:

Lawrence Tanner
Dept. of Geography and Geosciences
Bloomsburg University
Bloomsburg, PA 17815 USA
lhtann@planetx.bloomu.edu

Ted Nield
Geological Society of London
+44 (0) 20 7434 9944
ted.nield@geolsoc.org.uk

Ann Cairns
Geological Society of America
+01 303 447 2020 ext. 1156
acairns@geosociety.org

===============
(4) A DISTURBANCE IN THE "FORCE" CAUSED THE K-T IMPACT?

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

Geological Society of America
Boulder, Colorado

Contact:
Ann Cairns, Director-Communications
acairns@geosociety.org, 303-447-2020, ext. 1156

June 21, 2001

GSA Release No. 01-26

A Disturbance In the "Force" Caused the K-T Impact?

But this disturbance is more mysterious than Darth Vader. UCLA scientists
don't know exactly what it was, but they believe it occurred within the
Solar System 65 million years ago. The ensuing pandemonium upset Solar
System dynamics causing Mercury, Earth, and Mars to go off course.

"We speculate that it may also have perturbed asteroids in the inner part of
the asteroid belt, throwing one or more of them into Earth-crossing orbits,"
explained Bruce Runnegar, Director of UCLA's Center for Astrobiology. "Thus,
the ultimate cause of the K-T impact -- and demise of the dinosaurs -- may
have been a chaos-induced change in Solar System dynamics."

Runnegar will present the team's findings at the Earth Systems Processes
conference on Wednesday, June 27, in Edinburgh, Scotland. The Geological
Society of America and the Geological Society of London will co-convene the
June 24-28 meeting.

The other team members, Ferenc Varadi, a UCLA geophysicist, and Michael
Ghil, the Director of UCLA's Institute of Geophysics and Planetary Physics,
have worked for years on chaos in the Solar System and, in particular, the
role of in-step motions known as resonances in giving rise to the chaos.
This earlier work on resonances and chaos among the planets and the
asteroids prepared the ground for the present tantalizing results.

"In order to better understand the history of the inner Solar System over
hundreds of millions of years, we carried out several accurate, long-term,
numerical simulations of the orbits of the nine major planets using physical
models with increasing complexity," Runnegar said. "Our best calculations
show that the dynamical state of the inner Solar System changed abruptly
about 65 million years ago." Ghil added: "It is possible that it was a
transition through a special kind of resonance that produced the abrupt
change at the K-T boundary."

While scientists generally accept that there was indeed an extraterrestrial
impact 65 million years ago (at the Cretaceous/Tertiary or K-T boundary)
that wiped out most living species on Earth, they do not agree on the nature
of what caused that impact.

Was it an asteroid? Was it a comet? Now at least we have a better idea and a
vital clue to what really happened with this Earth-shaking event so many
millions of years ago.

CONTACT INFORMATION

During the Earth System Processes meeting, June 25-28, contact the GSA/GSL
Newsroom at the Edinburgh International Conference Centre for assistance
and to arrange for interviews: +44 (0) 131 519 4134

Ted Nield, GSL Science and Communications Officer
Ann Cairns, GSA Director of Communications

The abstract for this presentation is available at:
     http://gsa.confex.com/gsa/2001ESP/finalprogram/abstract_8024.htm

Post-meeting contact information:

Bruce Runnegar
Institute of Geophysics and Planetary Physics
University of California
Los Angeles, CA 90095-1567, USA
Office Phone: +01 310 206 1738
runnegar@ucla.edu

Ted Nield
Geological Society of London
+44 (0) 20 7434 9944
ted.nield@geolsoc.org.uk

Ann Cairns
Geological Society of America
+01 303 447 2020 ext. 1156
acairns@geosociety.org

==========
(5) ERRATIC PLANETS OR ERRATIC COMPUTER MODELS? SOLAR SYSTEM CHAOS BLAMED
FOR K/T MASS EXTINCTION

From the BBC News Online, 27 June 2001
http://news.bbc.co.uk/hi/english/sci/tech/newsid_1409000/1409305.stm

CHAOS CLUES TO DINO DEMISE

By BBC News Online's Helen Briggs

A mysterious disturbance in the forces at the heart of the Solar System
could have triggered the asteroid that wiped out the dinosaurs.

This intriguing new theory has been put forward by scientists who have
calculated the paths of the planets over the past 100 million years.

A US team believes a change in the dynamics of the Solar System caused
Mercury, the Earth and Mars to veer off course.

This could have pushed a giant asteroid towards our planet, spelling
downfall for most living things, 65 million years ago.

The idea has been floated by a team of astrobiologists at the University of
California, Los Angeles (UCLA), based on simulations of the historical
positions of the major planets.

"Our best calculations show that the dynamical state of the inner Solar
System changed abruptly about 65 million years ago," said Bruce Runnegar,
director of UCLA's centre for Astrobiology.

Chaos theory

The event modified the average orbit of Mercury, Mars and the Earth in
significant ways, he said, possibly perturbing asteroids in the inner part
of the asteroid belt and throwing one or more of them into Earth-crossing
orbits.

"Thus, the ultimate cause of the K-T impact [and the demise of the
dinosaurs] may have been caused by a chaos-induced change in Solar System
dynamics," Dr Runnegar told BBC News Online.

The planet Mercury could have triggered events
 
The basis of the theory, deduced by team members Ferenc Varadi and Michael
Ghil, is chaos in the Solar System.

Under this scenario, a small shift in the orbit of one or more planets could
destabilise much of the Solar System. To test their theory, the researchers
simulated the orbits of the major planets, working back in history over tens
of millions of years.

To their surprise, computer models pointed to a change in the dynamics of
the inner Solar System at the time of the K-T (Cretaceous-Tertiary) mass
extinction, about 65 million years ago, when many plants and animals
suddenly became extinct.

Dr Runnegar said they were now carrying out further studies to test their
theory.

"At the moment the link with the dinosaurs is based on a coincidence in time
and a plausible mechanism," he added.

'Tenuous' link

The research, presented at the Earth System Processes meeting in Edinburgh,
UK, has received a mixed reaction from other experts.

Professor Mark Bailey of the Armagh Observatory, Armagh, said the asteroid
link appeared tenuous, but not impossible.

"[It] relies not least on the assumption that the killer projectile was an
asteroid and not a comet," he told BBC News Online.

"Nevertheless, the idea that the resonant frequencies of the Solar System
change chaotically on time-scales of tens to hundreds of millions of years
(albeit only slowly and by relatively small amounts) is an interesting one
which adds yet another wrinkle to the story of our changing Solar System."

Professor Carlos Frenk, an astrophysicist at the University of Durham, UK,
said the theory appeared plausible.

"If these calculations are correct, they are very revealing of the unusual
past behaviour of the Solar System," he told BBC News Online.

"The past history of the Solar System was not as quiet as we thought - this
very unusual chaotic behaviour may have happened on our doorstep."

Copyright 2001, BBC

==========
(6) A COMMENT BY ALAN W HARRIS ON MPML

From Alan W. Harris <awharris@lithos.jpl.nasa.gov>
[as posted on the MPML mailing list <mpml@yahoogroups.com>

>GSA Release No. 01-26
>A Disturbance In the "Force" Caused the K-T Impact?
>.......
>"We speculate that it may also have perturbed asteroids in the inner part of
>the asteroid belt, throwing one or more of them into Earth-crossing orbits,"
>explained Bruce Runnegar, Director of UCLA's Center for Astrobiology. "Thus,
>the ultimate cause of the K-T impact -- and demise of the dinosaurs -- may
>have been a chaos-induced change in Solar System dynamics."

This is the kind of idle speculation hyping the press that is not worth
repeating. The chaotic change of terrestrial planet orbits 65 my ago may or
may not be verifiable, but the speculation that it triggered an "asteroid
shower" analogous to putative "comet showers" can be shot down in
a couple lines. Proposed "comet showers" have a decay time of around 10 my,
because the planet crossing comets are cleaned out, not by the terrestrial
planets, but by the giant planets, which are much more efficient at sweeping
out stuff crossing their orbits. Not so for NEAs that do not cross the giant
planet orbits. The clearing out time for NEAs is much longer, of order 100
MY.  The characteristic time of an earth impact is even longer, of order 300
MY for a single object.  Thus one would not expect an immediate response to
an injection of a "storm" of asteroids in Earth-crossing orbits in the form
of one or more impacts. If you injected enough to make a difference only 65
my ago, most of them would still be floating around out there waiting to hit
the Earth sometime in the future. That's not to say that chaotic anomalies
in orbits don't occur or don't contribute to the supply of NEAs, just that
the "response" time in terms of impacts is so slow that one cannot associate
a particular spike in the supply with a peak in impact rate within one or a
few million years. The timescale of removal of the objects is just too long.

Regards,

Alan

*******************************************************************
Alan Harris
Senior Research Scientist
MS 183-501                     Phone:  818-354-6741
Jet Propulsion Laboratory        Fax:  818-354-0966
Pasadena, CA 91109             email:  Alan.W.Harris@jpl.nasa.gov
*******************************************************************

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NOTICE: Material quoted or re-posted from the Minor Planet Mailing List
should be proceeded
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FROM THE MINOR PLANET MAILING LIST [date]. For the full text or to
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===========
(7) SNOWBALL FIGHT IN EDINBURGH

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

Geological Society of America
Boulder, Colorado

Contact:
Ann Cairns, Director-Communications
acairns@geosociety.org, 303-447-2020, ext. 1156

June 21, 2001

GSA Release No. 01-31

Snowball Fight In Edinburgh

The Snowball Earth theory has been gaining momentum since 1992 when Joseph
L. Kirschvink of the California Institute of Technology coined the term.
Kirschvink's initial model of an ice-covered Earth was just a beginning.
When Paul Hoffman of Harvard University and other colleagues picked up the
hypothesis, packed in more evidence, and tossed it to the science community
again, it really started to stick.

"This session brings together advocates, antagonists, and undecideds who are
experts in geology, atmospheric science, marine geochemistry, and
evolutionary biology," explained Paul Hoffman, the session chair. "They'll
bring a mix of new discoveries and contrasting perspectives on a highly
controversial Snowball Earth theory."

One debated issue concerns the role of methane in the snowball cycle.

Dan Schrag from Harvard University will propose a new, counterintuitive
model for the initiation of a snowball Earth. The model involves a slow leak
of methane from organic-rich sediments into an atmosphere that was less
destructive of methane (i.e. less oxidizing) than the present atmosphere.
Because methane is a very potent greenhouse gas (60x more powerful than CO2,
mole per mole), atmospheric CO2 levels would adjust downward to compensate
for a rise in methane. This is unstable, however, because any interruption
of the methane leak would result in rapid loss of methane through oxidation,
plunging the Earth into a global glaciation. The evidence such a scenario
comes from carbon isotopic records immediately prior to glaciation. This
methane 'trigger' for snowball events would be deactivated by a rise of
oxygen (a slow leak could not cause methane to build up because it would be
destroyed too rapidly). The advent of macro-animals is commonly attributed
to a rise in oxygen (which is needed both for their construction and
operation), which might explain why snowball events ceased after animals
appeared.

Martin Kennedy from the University of California, Riverside, will take a
different stand in his address, "The Snowball Earth: Myth or Methane?"
Kennedy will present physical, geochemical, and theoretical evidence for an
alternative model in which massive destabilization of ice-like methane gas
hydrates coincided with postglacial warming. Gas hydrates are an enormous
and highly unstable reservoir of potential greenhouse gasses (carbon dioxide
and methane) and are increasingly believed by paleoclimatologists to play a
critical role in Earth's climate system. Their deposition is favored by cold
climatic conditions and would have been at a maximum during the extremely
severe Neoproterozoic ice ages. In contrast to the snowball Earth
hypothesis, the model is based on a "conventional" modern climate system, but scaled to
the colder conditions implied by evidence for low latitude glaciation. The
deposition of cap carbonates and with unusual isotopic values is an expected
outcome of a large-scale methane release.

Another argument concerns a 'Slushball' Earth-an idea that predated the
Snowball Earth. One of the questions it now raises is: Did the tropical seas
remain open during Snowball Earth?

Simple climate models imply that ice-albedo feedback makes a partially
ice-covered planet unstable if ice cover exceeds ~50% surface area. The
instability results in total ice cover (i.e. so-called 'hard' snowball
Earth). Recently, more complex climate models suggest that a partially ice
covered planet may be stable (although simulation times do not exceed a few
decades) with up to 40% open water in the tropics. This so-called 'soft'
snowball, or 'slushball' Earth appeals to many biologists, who are concerned
for the survivability of eukaryotic algae and early micro-animals if any
existed. Bruce Runnegar from UCLA will make this argument at the session.
In fact, Joe Kirschvink's original snowball Earth hypothesis allowed for
patches of open water in the tropics, shifting back and forth across the
equator with the seasons.

The counter-arguments are the following: (i) the long-term stability of
'slushball' Earth solutions has not been demonstrated; (ii) ice lines will
rapidly recede as CO2 builds up due to complete continental ice cover
(eliminating crustal rock weathering which normally consumes CO2). Thus, a
'slushball' Earth will not be long-lived (as indicated by paleomagnetic
evidence), and would not produce iron-formations or cap carbonates, as
observed in the rock record; (iii) Sea ice in the tropics would be <20 m
thick, permitting algae to grow and micro-animals to feed even if no open
water were present.

The hydrological cycle on a Snowball Earth is another area of disagreement.

Geological evidence implies that mobile (i.e. thick, wet-based) glaciers
existed at least locally during Neoproterozoic ice ages. If the oceans were
ice covered, where would the moisture come from to allow glaciers to grow?
The presence of thick accumulations of glacial debris, it is argued, negates
a frozen ocean. Jim Walker (University of Michigan) has basically reached
the same conclusion, but not on the basis of geological evidence. His
arguments are based on climate theory and he will examine what the weather
would have been like on Snowball Earth. On theoretical grounds, he has come
to the conclusion that the surface of the ice would have melted during the
summer, providing a moist environment.

The counter argument is that ablation of sea ice in the tropics will provide
sufficient moisture for glaciers to slowly grow along elevated sea coasts
because of the lapse rate (decrease in air temperature, hence moisture-
holding capacity, with elevation). Because a Snowball Earth will be
long-lived (millions of years), even a very slow rate of glacier growth (10
cm annually) will make a ice 1000 m thick in 10,000 years. Modeling results
were presented at the recent American Geophysical Union meeting in Boston
supporting the buildup of thick glaciers on a Snowball Earth. Moreover, as
atmospheric CO2 builds up from volcanic outgassing, the Snowball Earth will
become warmer and warmer, increasing the sea ice ablation rates and the
glacier accumulation rates.

Another point of Snowball contention concerns the evidence for high orbital
obliquity.

Certain structures like ice or sand wedges are common in permafrost soils
and are normally attributed to large seasonal temperature fluctuations. In
South Australia, these structures occur in an area believed to have been
close to the equator when it was glaciated. Seasonal temperature
fluctuations are normally small near the equator (and diurnal fluctuations
are too rapid to produce the observed structures). The structures have been
interpreted (principally by George Williams at Adelaide University) as
indicating that the Earth had a high orbital obliquity during the
pre-Cambrian (i.e. a large angle between the equatorial and ecliptic
planes).

With very high obliquity (over 54 degrees), the tropics would be colder on a
mean annual basis than the polar regions, thus favoring low-latitude
glaciation. Grant Young (University of Western Ontario) will make this
argument in his presentation, "Is the Snowball a "No-ball"?: The Case
against the Snowball Earth Hypothesis."

"The occurrence of glaciers and highly variable seasonal temperatures in the
tropics is perhaps better explained by an Earth that was radically different
-- for example, the Earth's rotational axis may have been inclined at a much
higher angle than today's, throwing traditional latitude-related seasonality
into a spin," Young said. "Another possibility is that the Earth's magnetic
field was different in the geologic past -- instead of the familiar two
magnetic poles, the Earth's field may have had four or more, so that the
magnetic evidence of tropical glaciations may be spurious. There is no doubt
that the Earth underwent climatic convulsions twice in
its long history but we are far from understanding their causes or the
physical parameters that existed on Earth when they took place."

The arguments against high obliquity are as follows: (i) it results in hot
summers at all latitudes, which makes it difficult to for glaciers to grow;
(ii) widely observed sedimentary features (e.g. iron-formations, cap
carbonates, large stable isotope shifts) are not explained; (iii) there is
no credible mechanism to lower the obliquity at the end of the pre-Cambrian;
(iv) there may be other means of producing ice/sand wedges without strong
seasonality (e.g. surge-type glaciers). The latter point, at least, will be
brought up by Paul Hoffman for discussion during the Snowball Earth workshop
that immediately follows the session.

This is a sampling of a few of the arguments and different perspectives of
the Snowball Earth session that will take place in Edinburgh. While Paul
Hoffman 'promises' to keep silent as he fulfills his role as session chair,
that "hat" comes off when he enters the workshop when the real debates
begin. Weather forecast? Stormy and unpredictable.

CONTACT INFORMATION

During the Earth System Processes meeting, June 25-28, contact the GSA/GSL
Newsroom at the Edinburgh International Conference Centre for assistance and
to arrange for interviews: +44 (0) 131 519 4134

Ted Nield, GSL Science and Communications Officer
Ann Cairns, GSA Director of Communications

The abstract for this presentation is available at:
     http://gsa.confex.com/gsa/2001ESP/finalprogram/abstract_186.htm

Post-meeting contact information:

Paul Hoffman
Earth and Planetary Science
Harvard University
20 Oxford St.
Cambridge, MA 02138,
Office Phone: +01 617 496 6380
hoffman@eps.harvard.edu

Ted Nield
Geological Society of London
+44 (0) 20 7434 9944
ted.nield@geolsoc.org.uk

Ann Cairns
Geological Society of America
+01 303 447 2020 ext. 1156
acairns@geosociety.org

==========
(8) VENUS ANALOGUE OF CATASTOPHIC MANTLE OVERTURNS ON PRECAMBRIAN EARTH

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

Geological Society of America
Boulder, Colorado

Contact:
Ann Cairns, Director-Communications
acairns@geosociety.org, 303-447-2020, ext. 1156

June 21, 2001

GSA Release No. 01-23

Venus Holds Clues To Finding Earth's Platinum And Diamonds

Venus is key to understanding what the early Earth was like during the late
Archaean and early Proterozoic when precious resources were formed. While
modern Venus is in a quiet state most of the time, is does enter into short
periods of intense volcanic activity where the old surface of Venus is
destroyed and a new one is created. In its early history when life evolved,
Earth worked in a similar way to modern Venus.

Ghail will present his research, "A Venus Analogue of Catastrophic Mantle
Overturns on Precambrian Earth," at the Earth Systems Processes conference
on Wednesday, June 27, in Edinburgh, Scotland. The Geological Society of
America and the Geological Society of London will co-convene the June 24-28
meeting.

Ghail's research has focused on understanding how Venus works during its
prolonged quiet state. (But there is still considerable activity during
these relatively quiet periods.)

"I realized that there is a similarity between Venus and the early Earth
because both situations involve buoyant lithosphere (unlike modern Earth,
which is able to subduct its lithosphere)," he said. "I will argue that,
from the evidence from Venus, the early Earth did not have modern plate
tectonics, but did have something that looked similar to it, which explains
the confusing evidence from the geological record."

Ghail will also assert that since this situation is unstable on Venus today,
that the early Earth was the same way. Geologic evidence such as bursts in
continental growth and some apparently global outpourings of komatiite (very
high temperature) lavas support this idea.

His presentation is an assimilation of his and other scientists' varied
observations which explain several unanswered questions in the geology of
the early Earth.

CONTACT INFORMATION

During the Earth System Processes meeting, June 25-28, contact the GSA/GSL
Newsroom at the Edinburgh International Conference Centre for assistance and
to arrange for interviews: +44 (0) 131 519 4134

Ted Nield, GSL Science and Communications Officer
Ann Cairns, GSA Director of Communications

The abstract for this presentation is available at:
     http://gsa.confex.com/gsa/2001ESP/finalprogram/abstract_7777.htm

Post-meeting contact information:

Richard Ghail
Research Associate, Planetary Science
T.H. Huxley School, Imperial College
London, UK
Phone: 44 20 759 46436
ted.nield@geolsoc.org.uk

Ted Nield
Geological Society of London
+44 (0) 20 7434 9944
ted.nield@geolsoc.org.uk

Ann Cairns
Geological Society of America
+01 303 447 2020 ext. 1156
acairns@geosociety.org

==========
(9) THERE MAY BE SUBGLACIAL VOLCANOES (AND LIFE) ON MARS - MAY BE NOT

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

Geological Society of America
Boulder, Colorado

Contact:
Ann Cairns, Director-Communications
acairns@geosociety.org, 303-447-2020, ext. 1156

June 21, 2001

GSA Release No. 01-22

Subglacial Volcanoes (And Life?) On Mars

The search for liquid water is key for finding habitable environments on
Mars today -- places where prebiotic chemistry and/or life could still be
going on. Not surprisingly, the mantra, "Follow the Water," has become a
primary driver in NASA's new Mars Program. Water in liquid form is regarded
as essential for life. But how can we explore for life on Mars when liquid
water is unstable at the surface today due to an atmospheric density that is
only ~1/1000 of Earth's? This is a challenge we must overcome if we are to
mount a successful search for life on Mars.

While many scientists believe that liquid water could be present on Mars
today at a depth of several kilometers beneath the surface, we simply do not
yet have the technology to drill to those depths from the simple robotic
platforms we will be sending. At best, we can hope to drill a few meters to
perhaps tens of meters with current technologies. But what if there was
shallow ground water on Mars within a few meters of the surface? Then small
rovers and landers could probably drill and find it. This would better than
having to postpone exploring for deep subsurface water (and life) until
human astronauts could go to Mars and run deep drilling rigs. Humans will
probably not go to Mars for at least another twenty years. That's a long
time to wait! So can we do in the meantime?

Scientists are confident that there's water on Mars' polar caps. But that
water is perpetually frozen and unavailable for biology. But there could be
special geological exceptions where that water could exist as a liquid and
those potential "oases" (within the otherwise frozen deserts of the polar
regions) are important targets for astrobiology in the next two decades.

There is also speculation that very young channels and debris aprons found
on many north-facing slopes at high latitudes formed when liquid water
seeped out from the subsurface. To be liquid at those latitudes requires
that near surface water be both saline and warm, but probably still within
the range for life. Unfortunately all of the seep sites discovered so far
are on slopes inaccessible to landers and rovers.

One way to have liquid water under the polar caps at shallow depths would be
through subglacial volcanism. Such volcano-ice interactions could be going
on beneath the North polar cap of Mars today, or even within the adjacent
permafrost around the margins of the ice cap. On Earth, subglacial volcanic
eruptions are often associated with outbursts of water that create a variety
of distinctive geological features. On Mars, such outbursts of liquid water
could carry microbes and their byproducts to the surface where they could be
incorporated into ground ice and preserved. Such deposits could be easily
accessed by rovers in upcoming missions.

Meredith Payne and Jack Farmer from Arizona State University have been
focusing their recent research efforts on finding such environments on Mars.
They have studied all available Viking and Mars Orbiter Camera images taken
on and near the North polar cap searching for the tell-tale signs of
subglacial volcanic eruptions. This search has produced several potential
sites of probable recent volcano-ice interactions that will be reviewed and
compared with similar features in Iceland during a poster presentation on
Wednesday June 27 at Earth Systems Processes in Edinburgh, Scotland. The
Geological Society of America and the Geological Society of London will
co-convene the June 24-28 meeting.

"We are presently working to merge all Viking, MOC and Mars Laser Altimeter
(topographic) data into a spatially correlated base map for each area,"
Farmer said. "This effort will allow us to make detailed geologic maps and
establish age relationships between major rock units and terrain types. We
have been updating our mapping effort as new MOC and MOLA data become
available."

These correlated data sets will allow Payne and Farmer to refine hypotheses
concerning the origin of these features and test them through comparisons
with remote sensing of analogous landforms in Iceland of known origin.

"Discoveries in the last two decades have greatly extended the known range
of terrestrial habitats where life survives," Farmer explained. "Viable
microbial communities have been found living in deep (-2800 m) geothermal
groundwater at 349 K and pressures >300 bar. Furthermore, microbes have been
postulated to exist in basaltic rocks in rinds of altered volcanic glass.
All of these conditions could exist in polar regions of Mars today where
subglacial volcanism has occurred."

Payne and Farmer will soon begin fieldwork in Iceland to better understand
the processes associated with subglacial volcanism and the habitats for life
created by such processes.

CONTACT INFORMATION

During the Earth System Processes meeting, June 25-28, contact the GSA/GSL
Newsroom at the Edinburgh International Conference Centre for assistance and
to arrange for interviews: +44 (0) 131 519 4134

Ted Nield, GSL Science and Communications Officer
Ann Cairns, GSA Director of Communications

The abstract for this presentation is available at:
     http://gsa.confex.com/gsa/2001ESP/finalprogram/abstract_7445.htm

Post-meeting contact information:

Meredith C. Payne
Geological Sciences
Arizona State Univ
P. O. Box 1404
Tempe, AZ 85287-1404 USA
+01 480 965 0833
mcpayne@asu.edu

Jack D. Farmer
Geological Sciences
Arizona State Univ
P.O. Box 871404
Tempe CA 85287-1404 USA
+01 480 965 6748
jfarmer@asu.edu

Ted Nield
Geological Society of London
+44 (0) 20 7434 9944
ted.nield@geolsoc.org.uk

Ann Cairns
Geological Society of America
+01 303 447 2020 ext. 1156
acairns@geosociety.org

=============
(10) WHERE THERE'S SOUP, THERE'S LIFE

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

Geological Society of America
Boulder, Colorado

Contact:
Ann Cairns, Director-Communications
acairns@geosociety.org, 303-447-2020, ext. 1156

June 21, 2001

GSA Release No. 01-24

Where There's Soup, There's Life

But we're talking gourmet soup. That is, gourmet geochemical "primordial
soups" in hot springs and hydrothermal springs in the oceans that support
novel chemolithotrophic thermophiles. If we can understand these heat-loving
little critters, then we may confirm what microbial ecologist Anna-Louise
Reysenbach suspects -- they were the earliest ancestors of all life.

Early Earth was a hot environment, and it's possible that some of the life
that we see today in hot springs in places like Yellowstone National Park
and at deep-sea hydrothermal springs along mid-ocean ridges may share some
common metabolic features with their early Earth ancestors. So determining
what life exists in hot springs today is one of the first steps to define
what early life on a hot planet may have been like.

These thermophiles "living in hot springs are microscopic, and are hard to
identify just by looking at them under the microscope," explained Reysenbach
from Portland State University. She uses biogeochemical, molecular, and
microbiological approaches to study the ecology of thermophiles.

"Essentially there are two ways to identify these microbes; either by trying
to grow them, or by using molecular techniques that identify an
evolutionarily conserved gene, a sort of fingerprint, of the organism. Using
a combination of these approaches, we have been able to grow a very
prevalent and important member of hydrothermal ecosystems.

"This group of organisms are chemolithoautotrophs, they use inorganic energy
and carbon sources, and are the deepest lineage within the universal tree of
life," she explained. "Although the trunk and base of the tree of life are
much debated, these few pieces of evidence suggest that this group of
organisms may be a good proxy for studying early Earth life. Understanding
how these organisms fossilize, what remaining biological signatures they may
leave behind, how they precipitate minerals etc. will perhaps help us
interpret the rock record here on Earth and other planets more effectively."


The important member of this group is the Aquificales, a deeply-rooted
lineage that is common in both terrestrial and deep-sea hydrothermal
systems. Reysenbach looks forward to receiving the genome of one of the
isolates, "Persephonella marina," which will be available in a few months.

"I think it will definitely show what type(s) of carbon fixation pathways
this organism has, how it gets some of it's essential elements, N, C, P,
etc.," she said. "What I am also very interested in is how different or
similar it is to its relative Aquifex. When the genome sequence of Aquifex
was released, it rocked the boat a little, since it showed that this
organism is a VERY modern organism ... and not what some thought would be
typical of a 'primitive'-ancestral organism."

Reysenbach will present her research "Gourmet Geochemical "Primordial Soups"
at Hydrothermal Vents Support Novel Thermophilic Chemolithotrophs:
Implications for the Evolution of Life on Early Earth" on Wednesday, June
27, at the Earth Systems Processes conference in Edinburgh, Scotland. The
Geological Society of America and the Geological Society of London will
co-convene the June 24-28 meeting.

CONTACT INFORMATION

During the Earth System Processes meeting, June 25-28, contact the GSA/GSL
Newsroom at the Edinburgh International Conference Centre for assistance and
to arrange for interviews: +44 (0) 131 519 4134

Ted Nield, GSL Science and Communications Officer
Ann Cairns, GSA Director of Communications

The abstract for this presentation is available at:
     http://gsa.confex.com/gsa/2001ESP/finalprogram/abstract_8352.htm

Post-meeting contact information:

Anna-Louise Reysenbach
Department of Biology
Portland State University
Portland, OR 97201 USA
reysenbacha@pdx.edu

Ted Nield
Geological Society of London
+44 (0) 20 7434 9944
ted.nield@geolsoc.org.uk

Ann Cairns
Geological Society of America
+01 303 447 2020 ext. 1156
acairns@geosociety.org

==============
(11) THE GOLDILOCKS EFFECT: HOW OTHER EARTHS FORM JUST RIGHT

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

Geological Society of America
Boulder, Colorado

Contact:
Ann Cairns, Director-Communications
acairns@geosociety.org, 303-447-2020, ext. 1156

June 21, 2001

GSA Release No. 01-25

The Goldilocks Effect: How Other Earths Form Just Right

What does it take to make an Earth-like planet? It takes a stellar nursery
rich in carbon, oxygen, iron, and silicon in a combination that's not too
much, and not too little, but just right.

But these elements didn't exist right after the "big bang" 13 billion years
ago. They began to form in abundance in a strong burst of star formation
that lasted a few billion years, and the creation of Earth-like planets
became possible. But there is a catch. Too many of these ingredients seems
to be a bad thing for Earth formation. The 50 or so huge extrasolar planets
that we know about are in orbits that would destroy any Earth-like planets.
Dr. Charles H. Lineweaver, Research Fellow at the University of New South
Wales, calls this a Goldilocks effect: "with too few ingredients Earths are
unable to form, with too many, giant planets destroy any Earths trying to
form."

Lineweaver will present his research, " Formation of Terrestrial Planets in
the Universe: the First Critical Transition," at the Earth Systems Processes
conference on Wednesday, June 27, in Edinburgh, Scotland. The Geological
Society of America and the Geological Society of London will co-convene the
June 24-28 meeting.

Although the Earth is 4.55 billion years old, by cosmic standards the Earth
is the new kid on the block. By combining observations of extrasolar planets
and the rate of star formation in the Universe, Lineweaver has discovered
that compared to other Earth-like planets in the Universe, our Earth is
extremely young.

In a paper in press at the planetary science journal Icarus, Lineweaver
reported that "three quarters of the Earth-like planets in the Universe are
older than the Earth and their average age is 1.8 (plus or minus 0.9)
billion years older than the Earth."

Although the analysis is about terrestrial planets, not the life on them,
Lineweaver concluded that "If life forms readily on Earth-like planets -- as
suggested by the rapid appearance of life on Earth -- this analysis gives us
an age distribution for life on such planets and a rare clue about how we
compare to other life which may inhabit the Universe." The "rare clue" is
this: most of the life forms in the Universe have had two billion years
longer to evolve than we have. (To put this time span in perspective, two
billion years ago our ancestors were amoebas.)

Lineweaver's presentation at Earth Systems Processes includes an update on
the age distribution of terrestrial planets in the universe using data from
the most recent planet detections and new estimates of the star formation
rate. (For earlier work on this topic, see:
     http://xxx.adelaide.edu.au/abs/astro-ph/0012399.)

CONTACT INFORMATION

During the Earth System Processes meeting, June 25-28, contact the GSA/GSL
Newsroom at the Edinburgh International Conference Centre for assistance and
to arrange for interviews: +44 (0) 131 519 4134

Ted Nield, GSL Science and Communications Officer
Ann Cairns, GSA Director of Communications

The abstract for this presentation is available at:
     http://gsa.confex.com/gsa/2001ESP/finalprogram/abstract_7981.htm

Post-meeting contact information:

Dr. Charles H. Lineweaver,
Astrophysics
University of New South Wales
Sydney N/A 2052 Australia
charley@bat.phys.unsw.edu.au
PHONE: 61-2-9385-5168
FAX: 61-2-9385-6060

Ted Nield
Geological Society of London
+44 (0) 20 7434 9944
ted.nield@geolsoc.org.uk

Ann Cairns
Geological Society of America
+01 303 447 2020 ext. 1156
acairns@geosociety.org

=============
(12) AND FINALLY: PRIVATE ROCKET LAUNCH IS 'SUICIDAL'

From the BBC News Online, 26 June 2001
http://news.bbc.co.uk/hi/english/sci/tech/newsid_1407000/1407210.stm

By BBC News Online science editor Dr David Whitehouse

British rocket experts are denouncing as suicidal the latest plans of
controversial rocket engineer Steve Bennett.

If he goes ahead with them, he could well be killed, and the burgeoning
British rocketry effort will be permanently stuck on the launch pad, they
warn.

Their concerns were voiced as Bennett, from Manchester, prepared to unveil
his latest project, which he describes as the world's first private
spacecraft, at an exhibition in London.

He intends to become the first private astronaut to go into space with his
own rocket. Within two years, he hopes to take two passengers into space
with him. Critics are already calling it the "bye, bye, Bennett mission".

To boldly go

Steve Bennett's latest development is the Nova capsule.

Alongside it at the exhibtion will be a larger capsule called Thunderbird,
which Bennett hopes will take him, and the two passengers, into space.

But other rocket experts are worried, not least because the Thunderbird
capsule is actually a converted cement mixer, containing sheets of hardboard
and a few computer joysticks.

"This is not like launching an off-the-shelf rocket to a few tens of
thousands of feet," said British rocket expert Richard Osborne. "Getting to
the edge of space is a very different matter. You have to have expertise,
experience, tonnes of money and then test, test, test."

BBC News Online put these criticisms to Steve Bennett. He responded: "We are
not planning any tests such as wind tunnel or vibration tests before we
launch it. That is what the test flight is for."

'Ambitious project'

He confirmed that it was his intention for the Nova capsule to be launched
on a 3,050-metre (10,000-ft) shake-down mission by a cluster of commercially
available rocket motors all strapped together.

Richard Osborne told BBC News Online that the rockets Mr Bennett was using
each had a burn-time of six seconds, and if they all fired together would
subject him and his capsule to high G-forces that they might not be able to
withstand.

Even Steve Bennett's own team are surprised. Gurbir Singh, from Starchaser
Industries, the rocketeer's own company, told BBC News Online that the
mission was "somewhat ambitious".

Pete Davy, of Pete's Rockets, where many British rocket enthusiasts get
their rockets, was more blunt: "If he gets into that capsule and lights the
rockets it will be, bye, bye, Bennett."

But, despite these warnings, the Bennett launch schedule goes ahead. "I will
be the first private astronaut," he said.

Commit to launch

But has Bennett got the "right stuff" to go into space? He is an
accomplished parachutist but it will take more than that. In particular,
training in a centrifuge will be needed so that he, and any passengers, can
learn how to cope with the considerable G-forces, higher than those
experienced on Nasa's space shuttle.

"I've only been in a centrifuge briefly when I took a ride in the one at
Nasa's Johnson Space Center," Steve Bennett said. "I'll need more time. I'll
probably have to go to Russia for that."

But Nasa denies he has been anywhere near their centrifuge, which is owned
by the US Army and not at the Johnson Space Center anyway, and Singh said
that no centrifuge training had taken place.

In the media, Steve Bennett has been called "Britain's answer to Nasa".
Indeed, on his website, Bennett cites Nasa as one of his official sponsors.
Nasa denies this and when this was pointed out, Bennett said: "Er, that
might be an exaggeration, I'll look into that."

Within hours of this article appearing Nasa was removed from the list of
official sponsors on Starchasers website.

According to Starchaser Industries, two, as yet unnamed, passengers have
signed up to fly with Bennett for a fee that the company's website says is
500,000. In 1999, the company was offering a seat for 62,500.

If for any reason the mission does not go ahead, Bennett told us that their
money is secure. "If they don't fly they will get their money back."

X-Prize

Starchaser Industries says that the Thunderbird will be launched using a
"single, dependable, liquid-propellant engine". In the past, armed forces
and space agencies have sweated over such engines, spending many years and
enormous sums on them.

But according to Singh, the sweating at Starchaser Industries has yet to
begin, despite the launch date being less than 100 weeks away. He said that
little work had been done on the liquid-fuelled rocket. "This is an
aspiration. There are a couple of students looking at it," he said.

Bennett however, says something different: "I have the first prototype
engine on the desk in front of me. We plan to test it on a military site
later this year."

Rocket experts are somewhat puzzled by this, as Bennett has been banned, and
caused all other rocketeers to be banned from military launch ranges, after
he set fire to one when a rocket failed on launch a few years ago.

All agree that if Bennett is to get into space, and win the coveted $10
million X-Prize for the first private individual or company to do so, he
will have to raise his game.

Amateur record

Bennett's crowning achievement so far is "launching a rocket to 20,000 ft
(6096 m) that we believe is capable of going to 120,000 ft (36576 m). In
fact, I lead the field," he told BBC News Online.

But Pete Davy is unimpressed: "For 30 you can put together a rocket that
will reach 5,000 ft (1524 m). Sending a rocket to 20,000 ft (6096 m) can be
done for less than 1,000."

The current British amateur rocket altitude record is 34,579 ft (10,540 m).

John Bonsor, of Starr, a Scottish rocketry group is puzzled. "I don't
understand what is happening. He has been using cheap rockets, has a mixed
bag of success and disaster and has achieved less than many others have
working from their garage. It is ridiculous to claim that he leads the
field, except in the number of crashes."

"I've come from nothing to being the leading contender in the X-Prize,"
counters Bennett.

"Only if he reinvents the laws of physics," replies Bonsor. "He has
absolutely no chance of the X-Prize. Please don't launch."

Bennett's reply? "Just watch me. 'Seeing is believing', I say to my
critics."

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