PLEASE NOTE:


*

CCNet 142/2002 -  6 December 2002
--------------------------------


"Mars never had oceans as some researchers have claimed, but instead
is a cold, dry planet that was pounded by water- bearing asteroids and
showered with scalding rain that carved vast gullies and valleys.
This suggests the Red Planet was a less than favorable place for life
as we know it, a new study claims."
--Associated Press, 5 December 2002
 

"The possibilities of life on Mars have long fascinated authors and
musicians, from HG Wells to David Bowie. However, a British mission
supported by Damien Hirst and Blur could be in for disappointment
when it touches down on the Red Planet next Christmas. New research
published today suggests that the question to the oft repeated refrain, "Is
there life on Mars?" is simple: "No."
--Alastair Dalton, Scotsman, 6 December 2002


"The descendants of all these Martians still populate the films,
science-fiction novels and cartoons of today. We know their every
little way. Modern Martians travel by UFO. They wear skin-tight,
streamlined, silvery uniforms. They're obsessed with meeting people's
leaders (no messing about with middle management for them). And they
pop up in pop psychology books (masquerading as human men). If Martians
don't exist, it's not because we haven't done our best to invent them.
So what if they only inhabit the country of our minds?"
--The Times, 6 December 2002


(1) STUDY CASTS DOUBT ON LIFE EVER EXISTING ON MARS: PLANET TOO HOT, TOO DRY
FOR EVOLUTION
    The Associated Press, 5 December 2002

(2) SCIENTISTS SAY ANCIENT ASTEROIDS, COMETS MAY HAVE CAUSED MARS RAIN
    Andrew Yee <ayee@nova.astro.utoronto.ca>

(3) ENVIRONMENTAL EFFECTS OF LARGE IMPACTS ON MARS
    Science, 6 December 2002

(4) Q: IS THERE REALLY LIFE ON MARS? A: NO
    Scotsman, 6 December 2002

(5) IF MARTIANS DON'T EXIST, THEY STILL INHABIT THE COUNTRY OF OUR MINDS
    The Times, 6 December 2002

(6) ARCHAEAN ASTEROIDS: UPDATE OF CURRENT STUDIES OF IMPACT FALLOUT UNITS,
PILBARA CRATON,  WESTERM AUSTRALIA
    Andrew Glikson <Andrew.glikson@anu.edu.au>

(7) CHASING COSMIC ICEBERGS: THE ROSETTA MISSION AND THE EXPLORATION OF
COMETS.
    Peter Bond <PeterRBond@aol.com>

(8) AND FINALLY: GLOBAL WARMING IS GOOD FOR YOU 
    The Guardian, 5 December 2002


==============
(1) STUDY CASTS DOUBT ON LIFE EVER EXISTING ON MARS: PLANET TOO HOT, TOO DRY
FOR EVOLUTION

>From The Associated Press, 5 December 2002
http://www.sunspot.net/news/nationworld/bal-mars06,0,7226290.story?coll=bal%
2Dnationworld%2Dheadlines

WASHINGTON -- Mars never had oceans as some researchers have claimed, but
instead is a cold, dry planet that was pounded by water- bearing asteroids
and showered with scalding rain that carved vast gullies and valleys. This
suggests the Red Planet was a less than favorable place for life as we know
it, a new study claims.

The study, appearing this week in the journal Science, sheds new light on a
continuing debate by Mars researchers about how much water there was on
Mars, where it went and how it formed the planet's intricate pattern of
canyons, river beds and deltas.
 
Using photos and computer simulations, researchers at the University of
Colorado at Boulder concluded that immense asteroids pounded Mars 3.6
billion years ago, bringing vast quantities of water to the young planet and
releasing powerful shock waves of heat that melted existing underground
deposits of ice.

Owen B. Toon, senior author of the study, said at least 25 craters on Mars
were gouged out by asteroids 60 to 150 miles in diameter. The impact would
have propelled into the atmosphere millions of tons of superheated rock
vapor and melted ice. It also would have unleashed a blast wave heated to
more than 4,000 degrees and blanketed the planet with heated rock several
hundred feet thick.

"The atmosphere would be hotter than a self-cleaning oven," Toon said. "When
the water was released from the atmosphere, it would fall as scalding rain."

The blanket of hot rocks "would be a global thing, causing rivers to form
anywhere. The ice would be melting all over the planet," he said.

Based on the erosion features on Mars, the researchers estimated that after
a major impact, more than 150 feet of water would flow in some areas,
carving the river- like features. By some calculations, they said, there
could be many decades with rainfall of 6 feet per year.

Between impacts, Toon said, Mars would eventually cool, turning again into a
dry, chilled planet with water present only as subsurface ice.

"We believe these events caused short periods of a warm and wet climate, but
overall, we think Mars has been cold and dry for the majority of its
history," said co-author Teresa Segura.

Toon said that because the moist and warm periods were short, conditions
were not favorable for life to evolve on Mars.

Peter H. Smith, a University of Arizona planetary scientist, said that if
warmth and liquid water were available on Mars only episodically, "then you
have a pretty gloomy picture for life."

But he said there were other forces on Mars, particularly volcanic action,
that may have created subsurface pools where microscopic life could have
lived.

"In my opinion, they haven't closed the book on the prospects for the
evolution of life on Mars," Smith said.

He applauded the study, saying, "Assuming their calculations are correct,
this must have happened on Mars."

Ronald Greeley, a planetary researcher at Arizona State University, said the
study "has the potential to tie together several loose ends regarding Mars
surface history." Water ejected into the atmosphere by asteroid impacts, he
said, "could account for many of the apparently water-eroded features."

However, like Smith, he said hydrothermal systems powered by volcanic action
and subsurface brine pools could exist and would be favorable for evolution.


Copyright 2002, The Associated Press

=========
(2) SCIENTISTS SAY ANCIENT ASTEROIDS, COMETS MAY HAVE CAUSED MARS RAIN

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

Kathleen Burton
NASA Ames Research Center, Moffett Field, Calif.     Dec. 5, 2002      
      
Phone: 650/604-1731 or 604-9000
E-mail: kburton@mail.arc.nasa.gov

RELEASE: 02-126AR

SCIENTISTS SAY ANCIENT ASTEROIDS, COMETS MAY HAVE CAUSED MARS RAIN

Scientists from NASA and the University of Colorado suggest the bombardment
of comets and asteroids on early Mars caused cycles of rain that led to
global flooding and the formation of Mars' river valleys and other
water-sculpted landscapes.

The researchers emphasize that the period when large comets and asteroids
struck Mars appears to correlate with the formation of ancient rivers when
water once flowed on Mars, and that both 'events' seem to have ended about
the same time, between 3.5 billion and 3.8 billion years ago. The research
will be published on Dec. 6 in Science magazine in an article entitled
"Environmental Effects of Large Impacts on Mars."

"The river valleys and large craters on Mars may both be about the same age
geologically," said Teresa Segura, the paper's lead author. "We think that
the two must be related, and our paper describes one possible connection."
Segura, a graduate student in atmospheric and oceanic sciences at the
University of Colorado, is based at NASA Ames Research Center, in
California's Silicon Valley.

The researchers modeled the impacts of asteroids and comets between 60 miles
and 150 miles in diameter that bombarded Mars billions of years ago. Such
impact events packed a huge energy wallop, equal to about 10,000 million
megatons of TNT depending on collision velocities, which were lower back
then.

The impacts released water on Mars in four ways, the scientists say -- from
the vaporized asteroid or  comet itself, from Mars' icy polar caps, from the
ground where the crater formed and
from the heat from hot 'ejecta' (a mixture of soil, rocks and water) that
gradually baked water out of the martian soil.

When Mars eventually cooled down after an impact episode, scientists
theorize, water that had evaporated into the atmosphere condensed into rain.
During Mars' rainy periods, precipitation rates probably averaged between 1
meter and 2 meters a year, similar to Earth's average annual rainfall today.

"This happened dozens of times, maybe more, but after it rained, Mars would
go dry," said Dr. Kevin Zahnle, a co-author from NASA Ames. "In the times
between impacts, the water sank back into the soil, where it lay dormant
until the next time an impact occurred."

Scientists think the martian rains lasted for episodes ranging from months
to decades and that, between bombardments, Mars returned to its typical
cold, dry state. Besides bringing moisture, the impacts also caused Mars to
warm up, they say. During bombardment episodes, hot 'ejecta' from impacts
kept Mars' surface warm for hundreds of years at a time.

The martian cratering record shows that there are at least 30 craters carved
by impactors that are 100 kilometers or more in diameter. These were created
during the planet's period of heavy bombardment by comets and asteroids more
than 3.5 billion years ago.

Scientists do not know why a late heavy bombardment stopped about 3.5
billion years ago, according to Segura. "Our research provides some insight
into what early Mars might have been like, but we've fit only a couple of
pieces into the puzzle of Mars' past," Segura said.

Team members include Dr. Owen B. Toon, University of Colorado, and Dr.
Anthony Colaprete, NASA Ames.

The project is funded by the University of Colorado Center for Astrobiology
in Boulder, and the NASA Astrobiology Institute (NAI) through NASA Ames
Research Center. The NAI is an international research consortium with its
central offices located at NASA Ames.

NOTE TO EDITORS AND NEWS DIRECTORS: You are invited to a special session at
the American Geophysical Union (AGU) meeting titled "Mysteries of the
Martian Rivers," to be held on Dec. 6 from 2 p.m. to 4 p.m. PST in the
Moscone Convention Center (MCC) Theatre, Exhibit Hall C, San Francisco. The
session is an oral debate and discussion about the formation of rivers and
valleys on Mars. After the session, researchers will be available for
follow-up questions from the media in the MCC Press Room between 4 p.m. and
5 p.m. PST. In addition, there will be a poster session on the topic
beginning at 8:30 a.m. PST on Dec. 6 in MCC Hall D (P51B).

===========
(3) ENVIRONMENTAL EFFECTS OF LARGE IMPACTS ON MARS

>From Science, 6 December 2002
http://www.sciencemag.org/cgi/content/abstract/298/5600/1977
(registration required)

Teresa L. Segura,Owen B. Toon, Anthony Colaprete, Kevin Zahnle

The martian valley networks formed near the end of the period of heavy
bombardment of the inner solar system, about 3.5 billion years ago. The
largest impacts produced global blankets of very hot ejecta, ranging in
thickness from meters to hundreds of meters. Our simulations  indicated that
the ejecta warmed the surface, keeping it above the freezing point of water
for  periods ranging from decades to millennia, depending on impactor size,
and caused shallow  subsurface or polar ice to evaporate or melt. Large
impacts also injected steam into the  atmosphere from the
craters or from water innate to the impactors. From all sources, a typical
100-, 200-, or 250-kilometers asteroid injected about 2, 9, or 16 meters,
respectively, of precipitable water into the atmosphere, which eventually
rained out at a rate of about 2 meters per year. The rains from a large
impact formed rivers and contributed to recharging aquifers.

Science, Volume 298, Number 5600, Issue of 6 Dec 2002, pp. 1977-1980.
Copyright 2002 by The American Association for the Advancement of Science.
All rights reserved.

============
(4) Q: IS THERE REALLY LIFE ON MARS? A: NO

>From Scotsman, 6 December 2002
http://www.news.scotsman.com/scitech.cfm?id=1356332002

ALASTAIR DALTON SCIENCE CORRESPONDENT

THE possibilities of life on Mars have long fascinated authors and
musicians, from HG Wells to David Bowie.

However, a British mission supported by Damien Hirst and Blur could be in
for disappointment when it touches down on the Red Planet next Christmas.

New research published today suggests that the question to the oft repeated
refrain, "Is there life on Mars?" is simple: "No."

Mars is an unpromising place for supporting life because it is a cold, dry
planet that only became warm and wet for short periods while being bombarded
by water-filled asteroids, US scientists claim.

They believe Mars is even less hospitable than previously thought - because
the scalding rains from the asteroid impacts which carved vast gullies into
the surface were followed by long icy droughts.

However, the Beagle 2 team, whose landing craft blasts off for Mars next
May, can take heart from other experts who believe volcanic activity may
have created underground water pools conducive to life.

The mission, which is named after the ship which took Charles Darwin on his
voyage of discovery, has again sparked the imagination of artists who follow
on from HG Wells, who wrote The War of the Worlds, about a Martian invasion
of Earth, and David Bowie who recorded the Life on Mars album.

Beagle 2's search for life will be aided by an instrument calibration chart
and sample colour guide painted by Damien Hirst, while a musical call sign
to Earth has been composed by members of Blur.

Dr Teresa Segura, of the University of Colorado, at Boulder, who led the new
research, said it rejected previous theories that Mars' network of valleys
were formed in a long-lasting greenhouse climate that teemed with life in
warm, wet conditions.

She explained: "In contrast, we envision a cold, dry planet; an almost
endless winter broken by episodes of scalding rains followed by flash
floods.

"Only during the brief years or decades after the impact events would Mars
have been temperate, and only then might it have bloomed with life. "

However, Dr Segura added: "The short duration of the warm episodes may have
made it challenging for life to establish itself on Mars in the first
place."

The researchers used photographs of Mars and computer simulations to build
up a detailed picture of its past.

Their study, which is published in the journal Science, concluded that huge
asteroids up to 150 miles in diameter pounded Mars almost four billion years
ago. The impacts emptied vast quantities of water on to the surface and
released powerful blast waves of more than 2,200C that melted underground
ice deposits.

The network of valleys also created were claimed, in 1906 by the American
astronomer Percival Lowell, to be canals constructed by Martians.

Dr Owen Toon, a member of the research team, said: "The atmosphere would be
hotter than a self-cleaning oven. When the water was released from the
atmosphere, it would fall as scalding rain."

The scientists have estimated more than 150ft of water fell in some areas,
followed by many decades of rainfall of 6ft a year.

Dr Toon said the volume of water would have carved features into Mars's
surface, but between impacts, the planet would have cooled into a dry,
chilly desert.

Dr Peter Smith, a planetary scientist at the University of Arizona, said
that if warmth and liquid water were available on Mars for only intermittent
periods "then you have a pretty gloomy picture for life".

However, he said there were other forces on the planet, particularly
volcanic action, that may have created subsurface pools of water where
microscopic life could have lived.

He said: "In my opinion, they haven't closed the book on the prospects for
the evolution of life on Mars."

Dr Ronald Greeley, a planetary researcher at Arizona State University,
agreed the latest findings were not conclusive. He said the study "doesn't
put a nail in the coffin" for the evolution of life on Mars because
hydrothermal systems powered by volcanic action and underground salt-water
pools may still exist and would be favourable for the evolution of life.

Professor Colin Pillinger, the lead scientist for the Beagle 2 mission,
brushed off the latest claims as irrelevant: "This does not reduce the
chances of life. We know there have been large amounts of water on Mars for
three million years.

"This will not stop us from sending a craft there to look for life. There is
still clear evidence from a Martian meteorite that liquid water is trickling
around. A little water is all you need for micro-organisms."

Other scientists believe life may have survived deep underground, following
the discovery of microbes several miles beneath the Earth's surface.

An exhibition about the two Beagle expeditions opens at the National
Maritime Museum, in London, today and runs until September. 

Copyright 2002, scotsman.com 

==================
(5) IF MARTIANS DON'T EXIST, THEY STILL INHABIT THE COUNTRY OF OUR MINDS
 
>From The Times, 6 December 2002
http://www.timesonline.co.uk/article/0,,542-504252,00.html

Life on Mars
Scientists can't take the Martians out of our minds
 
It is a truth universally acknowledged that a planet as near our own Earth
as Mars is in need of little green men to live on it and visit us. Ever
since mankind realised that the stars that filled the night skies were an
infinite number of other planets, suns and galaxies, the belief that we are
the only intelligent life form in that empty, spinning universe has made us
feel a little lonely. When we look at the heavens, it's natural to hope that
companionship might be somewhere out there. And where better to find it than
in the reddish glow of the closest planet, so instantly visible that
Classical writers likened it to the fiery, belligerent god of war, which
stands brilliantly out against paler, remoter stars to this day?

Now the latest scientific research says it is unlikely life could ever have
existed on Mars. Its frozen oceans may have melted, briefly, whenever
asteroids smashed into the red planet - but not for long enough to breed the
microbes and micro-organisms that might, eventually, have turned into short,
tubby men with glistening green skin, lots of limbs and eyeballs on stalks.

That may be fact. But it's a churlish kind of science that denies us the
pleasure of believing that these cosmic cousins are waiting in space for us
to find them.

Our need for Martians stretches back through the centuries to the
philosopher Immanuel Kant. In 1755, he pictured them as "light, wispy
creatures" with intellects more powerful than ours. A century later, the
Italian astronomer Giovanni Schiaparelli observed about 100 "canali"
(Italian for "channels") on the surface of Mars; astronomers decided they
might be huge bands of vegetation bordering irrigation ditches dug by
intelligent beings to carry water from Mars's polar ice-caps.

H.G. Wells also fantasised about meetings with men from space, though
Wells's Martians were an altogether feistier bunch of 20th-century horrors
with tentacles and death rays trained on the residents of Surrey. C.S. Lewis
made them over in religious shape, and created languages for both the shaggy
round seal-like ones and the very tall skinny ones.

The descendants of all these Martians still populate the films,
science-fiction novels and cartoons of today. We know their every little
way. Modern Martians travel by UFO. They wear skin-tight, streamlined,
silvery uniforms. They're obsessed with meeting people's leaders (no messing
about with middle management for them). And they pop up in pop psychology
books (masquerading as human men). If Martians don't exist, it's not because
we haven't done our best to invent them. So what if they only inhabit the
country of our minds?
 
Copyright 2002 Times Newspapers Ltd.

========
(6) ARCHAEAN ASTEROIDS: UPDATE OF CURRENT STUDIES OF IMPACT FALLOUT UNITS,
PILBARA CRATON,  WESTERM AUSTRALIA

>From Andrew Glikson <Andrew.glikson@anu.edu.au>

The nature of the early Earth remains shrouded in mystery. Deciphering the
geological record of the Pilbara terrain, northwestern Australia - one of
the very few areas world-wide where 3500 to 2200 million years old rocks are
well preserved - provides vital insights into the nature of early
terrestrial environments. Despite intensive studies over the last 30 years
or so, views remain divided regarding the origin of the extensive volcanic
outpours and intercalated sediments, the so-called "greenstone belts", which
characterize the Archaean era (3800 to 2600 million years), with
implications to early habitats of life - mainly bacterial mats or
Stromatolites.

Pioneering and detailed research of asteroid impact fallout units in the
Pilbara Craton (Lowe and Byerly, 1986; Byerly et al., 2002; Simonson, 1992;
Simonson and Hassler, 1997; Simonson et al., 1998, 2000a,b; Hassler et al.,
2000; Hassler and Simonson, 2001) identified microkrystite (impact
vapor-condensate) spherules and microtektite (impact melt fragments and
droplets)-rich units, included identification of:

(a) bands, lenses and dispersed microspherules in ~3.46 Ga chert/arenite
intercalations in the Apex Basalt, Warrawoona Group;
(b) >2.63 Ga spherule lenses and spherule-bearing intraclast conglomerate
(JIL) associated with the transition from the Jeerinah Formation to the
Marra Mamba Iron Member;
(c) stratigraphically consistent spherule beds in the 2.56 Ga
shale/carbonate Bee Gorge Member, Wittenoom Formation (SMB) and in possibly
contemporaneous tsunami-disrupted carbonates of the Carawine Dolomite (STM),
and
(d) thick (<80 cm) spherule-rich units in 2.49 Ga S4 Macroband of Dales
Gorge Member (S4M), Brockman iron Formation.

Recent and ongoing studies (Glikson and Vickers, 2002) indicate (1)
identification of microkrystite-bearing conglomerate located
stratigraphically about 200 m below the original impact fallout unit of the
Apex Basalt and microkrystite-bearing chert pebbles (Lowe and Byerly, 1986),
indicating multiple impacts and intermittent volcanism; (2) suggested
multiple impacts in the SMB, Wittenoom Formation, based on consistent
undisturbed intermediate sediments; (3) observation of Ni-rich Fe oxides in
the JIL and S4M, and of Nickel metal, oxide, sulphide, and arsenide
micron-scale particles in the S4M; (4) identification of high Ni/Co, Ni/Cr,
Ni/Mg and Ni/Fe ratios in microkrystites, consistent with meteoritic
contributions; (5) identification of low Pd/Ir and Pt/Ir ratios in
microkrystites, interpreted in terms of loss of volatile PGE (Pd, Au)
relative to more refractory PGE (Ir, Pt) upon microkrystite condensation.
Complete gradations are observed between vapor condensate products
(microkrystite spherules) and meta-glass particles (fragmental
microtektites), attesting to melt/volatile fractionation in the vapor cloud.
The domination of pseudomorphs of quench crystallites (after ?olivine and
?pyroxene) and of chlorite in spherules and the apparent absence of shocked
PDF-bearing quartz grains support the suggestion by Simonson et al. (1998)
of oceanic impact sites. 

The dominance of K-feldspar shells in microkrystites and microlitic
K-feldspar in microtektites may be attributed to resorbtion of potassium
from sea water into settling glass droplets and fragments, followed by
devitrification represented by characteristic inward-radiating K-feldspar
crystal fans first described by Simonson (1992). Preservation of Ni metal
particles and quench ilmenite within the K-feldspar places limits on
subsequent deuteric/burial alteration. Attempts at determining the K-Ar and
O isotopes of the K- feldspars (T. Uysal and S. Golding, in progress) may
clarify temperature and age parameters.

Regional mapping of the microkrystite and microtektite-bearing tsunami
mega-breccia marker unit (STM) of the lower Carawine Dolomite in the East
Pilbara (Rippon Hills and Warrie Warrie Creek area) indicates a distribution
over an area in excess of 100 km N-S. The chaotic-structured megabreccia is
interpreted in terms of autochthonous to subautochthonous tsunami disruption
of the sea bed, including excavation of consolidated sedimentary substratum,
attested by meter-scale blocks and near-absence of imbricated mass-flow
structures. Deformed semi-ductile blocks are present. Field relations
indicate injection of liquefied microkrystite-rich muds/microbreccia into
fractures in the substratum under hydraulic pressures in excess of
friction/grinding pressures, evidenced by near-perfect preservation of
impact spherules and microtektites within breccia and microbreccia veins.
The correlation of Pb-Pb whole rock carbonate age of the STM with the 2.56
Ga age of the SMB (Woodhead et al., 1998) supports their contemporaneity and
a propagation of the tsunami wave from NE to SW suggested by Simonson and
Hassler (1997) and Hassler and Simonson (2001). Meter-size chert and BIF
boulders within the S4M impact fallout unit are interpreted as erratic
tsunami-transported blocks.

The few hundred micron-scale of Warrawoona Group microkrystites, with
ensuing difficulty in field identification, suggests possible more extensive
occurrences and encourages further field search. The close similarity in
appearance between S4M-type impact fallout units and fine volcanic ash
likewise justifies further investigation of the Brockman Iron Formation and
similar units. Considering the methodological difficulties in field
recognition of new impact fallout units, impact signatures may be more
common in Archaean terrains than hitherto recognized, with significant
implications for the understanding of the origin of the early terrestrial
crust.

References
Byerly, G.R., Lowe, D.R., Wooden, J.L., Xiaoogang Xie, 2002, Science,
297:1325-1327;  Hassler, S.W., Robey, H.F., and Simonson, B.M., 2000,
Sedimentary Geology, 135:283-294. Hassler, S.W., and Simonson, B.M., 2001,
J. Geology, 109:1-19;  Lowe, D.R. and Byerly, G.R., 1986. Geology, 14:
83-86; Simonson, B.M., 1992, Geol. Soc. Am. Bull., 104: 829-839;  Simonson,
B.M. and Hassler, S.W., 1997. Aust.J. Earth Sci., 44: 37-48;  Simonson,
B.M., Davies, D., Wallace, M., Reeves, S. and Hassler, S.W., 1998. Geology,
26: 195-198; Simonson, B.M., Davies, D. and Hassler,  S.W., 2000a, Aust. J.
Earth Sci., 47:315-325;  Simonson, B.M., Hornstein, M. and Hassler, S.W.,
2000b, in Eds I. Gilmour and C. Koeberl, Springer-Verlag, Lecture Notes in
Earth Sciences, v. 92, pp. 181-214; Lowe, D.R. and Byerly, G.R., 1986,
Geology, 14:83-86;  Woodhead, J.D., Hergt, J.M., and Simonson, B.M., 1998.
Geology, 26:47-50. 

Andrew Glikson
Research School of Earth Science
Australian National University
Canberra, ACT 0200
Andrew.glikson@anu.edu.au

==========
(7) CHASING COSMIC ICEBERGS: THE ROSETTA MISSION AND THE EXPLORATION OF
COMETS.

>From Peter Bond <PeterRBond@aol.com>

ROYAL ASTRONOMICAL SOCIETY PRESS INFORMATION NOTE
FOR IMMEDIATE RELEASE
Date: 4 December 2002

Ref.: PN 02/30

Issued by:

Peter Bond,
RAS Press Officer (Space Science).
10 Harrier Close
Cranleigh
Surrey
GU6 7BS
United Kingdom.
Tel: +44 (0)1483-268672
Fax: +44 (0)1483-274047
E-mail: PeterRBond@aol.com

RAS Web: http://www.ras.org.uk/

CONTACT DETAILS, AS WELL AS SOURCES OF IMAGES AND FURTHER INFORMATION ARE
LISTED AT THE END OF THIS RELEASE.
***********************************************************

CHASING COSMIC ICEBERGS:
THE ROSETTA MISSION AND THE EXPLORATION OF COMETS.

A Royal Astronomical Society Discussion Meeting entitled "COMETARY SCIENCE
AT THE LAUNCH OF ROSETTA" will be held on FRIDAY 13 DECEMBER 2002 in the
Lecture Theatre of the Geological Society, Burlington House, Piccadilly,
London W1.

The meeting will bring together world-renowned experts from the UK, the
European Space Agency (ESA), Germany, France and the USA. On the agenda are
discussions about the nature of comets and in-depth presentations about two
revolutionary space projects: ESA's Rosetta mission to orbit and land on a
comet, and NASA's Deep Impact mission to blast a crater in a comet nucleus
and analyse the debris.

Members of the media are invited to attend the meeting free of charge,
although advance notice of attendance to Peter Bond, RAS press officer for
space science (see details above), would be appreciated.

Among the highlights of the meeting will be presentations by Dr. Rita
Schulz, an interdisciplinary scientist and Deputy Project Scientist for the
Rosetta mission; and Professor Michael A'Hearn, Principal Investigator for
NASA's Deep Impact mission.

Other key speakers include:
Dr. Jean-Pierre Bibring (Institut d'Astrophysique Spatiale, Universite Paris
Sud, Orsay, France), who will be describing scientific research to be
undertaken by the Rosetta Lander.
Dr. Ian Wright (The Open University), Principal Investigator for the
"PTOLEMY" experiment, one of the most advanced instruments on the Rosetta
Lander and the UK's main scientific contribution to the Rosetta mission.
Chris Carr (Imperial College, London), one of the joint Principal
Investigators of the Rosetta Plasma Consortium. Imperial College provided
the data processing and plasma interface unit for the RPC sensors.
Dr. Jens Biele (German Aerospace Centre, Cologne, Germany) who will describe
how to catch and land on a comet.

The organisers of the meeting are Dr. Geraint Jones (Imperial College,
London) and Dr. Simeon Barber (Open University, Milton Keynes).

COMETS.

Comets are traditionally described as "dirty snowballs" because they are
very light and composed largely of ices overlain by a dark crust whose
composition remains a mystery.

Most comets linger unseen in the dark depths of the outer Solar System, but
occasionally one is disturbed and sent plummeting towards the Sun. As its
ices vaporise, the comet develops a coma and whispy tails made of gas and
dust.

Some comets are disturbed or even captured into short-period orbits by
gravitational interactions with the giant planets. Both Comet Wirtanen and
Comet Tempel 1, the targets of Rosetta and Deep Impact respectively, belong
to the Jupiter family of periodic comets. They commute from the orbit of
Jupiter to the orbit of the Earth and back again once every 5 years.

ROSETTA AND DEEP IMPACT.

The RAS meeting will take place only one month prior to the launch of the
European Space Agency's pioneering Rosetta mission to explore Comet
Wirtanen, which is currently scheduled for the night of 12-13 January 2003.

After launch from Kourou spaceport in French Guiana on board a heavy-lift
Ariane 5 rocket, Rosetta will spend almost nine years travelling around the
inner Solar System until it finally rendezvous with Comet Wirtanen in
November 2011.

In order to catch up with the fast-moving comet, Rosetta will receive
gravitational boosts during close flybys of Mars (26 August 2005) and Earth
(28 November 2005 and 28 November 2007). It will also make two excursions
into the main asteroid belt, when it will gather the first close-range
observations of two contrasting chunks of primitive rock, a 110 km wide
asteroid named Siwa and a tiny asteroid named Otawara.

In the summer of 2012, when the Rosetta Orbiter is circling within one
kilometre (0.6 miles) of Wirtanen's nucleus, the 100 kg Lander will drop
gently onto its coal-black surface to make the first in situ measurements of
one of these 'dirty snowballs'.

The Orbiter will then spend another 12 months chasing the comet during its
headlong plunge towards the Sun. Rosetta will examine at close quarters the
dramatic changes that take place as Wirtanen's ices vaporise in the warmth
of the Sun, generating bright jets of gas and dust that feed an
all-enveloping coma. The 11 year odyssey will end when the comet and
spacecraft return to the vicinity of Earth's orbit in July 2013.

Deep Impact is a smaller, less ambitious NASA mission which is designed to
discover the secrets of what comets are made of. Its two components - a
flyby spacecraft and a 350 kg (771 pound) impactor - will be launched
together in early 2004 and travel to Comet Tempel 1, where they will
separate and operate independently.

The flyby spacecraft will release the impactor into the comet's path, then
watch as the 'missile' collides with the comet, making a football
field-sized crater in its nucleus. The impact is scheduled for 4 July 2005.
As the gases and ice inside the comet are exposed and expelled outward by
the impact, the flyby spacecraft will take pictures and measure the
composition of the outflowing gas.

THE PROGRAMME

10:00    Registration and Coffee

MORNING SESSION      Chair: Dr Geraint Jones

10:30   Dr. Rita Schulz (Research and Scientific Support Department
of ESA):
    Rosetta goes to Comet Wirtanen.

10:55   Dr. Jens Biele (German Aerospace Centre, Cologne, Germany):
    How to catch and land on a comet.

11:15   Dr Jean-Pierre Bibring (Institut d'Astrophysique Spatiale,
Universite Paris Sud, Orsay, France):
    In-situ science on a comet - the Rosetta Lander.

11:40   Dr. Ian Wright (The Open University):
    PTOLEMY (a gas analysis experiment on the Rosetta Lander)

11:55   Professor Iwan P. Williams (Queen Mary, University of
London):
    CONSERT (a sounding experiment to probe the interior of the
comet's nucleus)

12:10   Chris Carr (Imperial College, London):
    The Rosetta Plasma Consortium.

12:25   Dr. Andrew J. Coates (Mullard Space Science Laboratory,
University College London):
    The cometary plasma environment: current knowledge and
prospects for Rosetta.

12:50    LUNCH (a light lunch will be available for purchase)

AFTERNOON SESSION          Chair: Dr Simeon Barber

13:50   Dr. Alan Fitzsimmons (Queen's University Belfast):
    Observing Distant Comets and the Nucleus Size Distribution.

14:10   Prof. David W. Hughes (University of Sheffield):
    The Size Distribution of Nuclei and its Evolution with Time.

14:30   Prof. Michael F. A'Hearn (Dept. of Astronomy, University of
Maryland, USA):
    Diversity among NASA's cometary missions.

14:55   Dr Mark J. Burchell & Ellen Johnson (University of Kent):
    Laboratory studies of what an impact in a porous ice target
(e.g. comet nucleus) might look like.

15:10   Dr. Jonathan Shanklin (British Astronomical Association):
    Amateur contributions to cometary science.

15:20   Discussion - what are the outstanding questions in cometary
science?

15:30   TEA - At the Scientific Societies Lecture Theatre, 23 Savile
Row, London W1 (within walking distance of Burlington House) followed by the
A&G (ORDINARY) MEETING, which is also open to the media. Dr. Rita Schulz
(Rosetta Deputy Project Scientist) and Professor Michael A'Hearn (PI of the
Deep Impact mission) will be speaking at this meeting.

FOR FURTHER INFORMATION ABOUT THE MEETING CONTACT:

Dr. Geraint Jones
Space & Atmospheric Physics Group
The Blackett Laboratory
Imperial College
London
SW7 2BW
Tel: +44 (0)20-7594-7774
Fax: +44 (0)20-7594-7772
E-mail: g.h.jones@ic.ac.uk

Dr. Simeon Barber
Planetary and Space Science Research Institute
Open University
Walton Hall
Milton Keynes
MK7 6AA
Tel: +44 (0)1908-659517
Fax: +44 (0)1908-858022
E-mail: s.j.barber@open.ac.uk

IMAGES AND FURTHER INFORMATION CAN BE FOUND ON MANY WEB SITES INCLUDING:

Rosetta mission: 
http://sci.esa.int/rosetta/

Imperial College of Science, Technology and Medicine:
http://www.sp.ph.ic.ac.uk/Rosetta/

Mullard Space Science Laboratory (UCL):
http://www.mssl.ucl.ac.uk/www_plasma/homepage.html

Planetary and Space Science Research Institute, Open University:
http://psri.open.ac.uk/missions/mis-ros.htm

NSSDC information and images for comets and asteroids:
http://nssdc.gsfc.nasa.gov/planetary/planets/asteroidpage.html

Deep Impact mission:
http://deepimpact.jpl.nasa.gov

=======
(8) AND FINALLY: GLOBAL WARMING IS GOOD FOR YOU 

>From The Guardian, 5 December 2002
http://www.guardian.co.uk/comment/story/0,3604,854050,00.html

The world's climate has always changed and that should not scare us. We
should just be prepared

Duncan Steel
Thursday December 5, 2002
The Guardian

There can be little doubt that global warming is real. When scientists argue
about the subject, it is usually in the context of how large a temperature
rise they have calculated for the next decade or century, not whether any
heating at all will occur. The heat is on, then. At least I hope so: because
the greenhouse effect is a good thing.

Consider historical records, and other tracers showing how our climate has
varied over the past few millennia. Stepping back just a decade, we find
that injections of dust or smoke into the atmosphere, such as from the Mount
Pinatubo volcanic eruption and the oil fires after the Gulf war, led to
slight coolings (airborne particles reflect sunlight away). Going back to
the 17th century, one notes the "Little Ice Age" when the River Thames froze
over and frost fairs were held in London on its icy surface. This occurred
during an era when there was a dip in sunspot numbers, and so was presumably
caused by lessened solar output. Why, we don't know. But it happened.

Starting around AD540, pestilence spread across Europe. This is usually
termed the Plague of Justinian (emperor of the eastern Roman Empire), and it
was provoked by a climatic downturn. Similarly, several coincidental crashes
of disparate, well-separated civilisations are recognised in archaeological
records, for example around 1650BC and also 2350BC, with no apparent link
other than widespread worsening climate.

So, relatively small perturbations in the amount of sunlight reaching the
ground can lead to temperature falls sufficient to provoke the downfall of
previously effective agricultural systems and economies.

Looking at the climate over an extended timescale, longer than the Holocene
(the relatively warm past 12,000 years), one sees that the usual condition
of Earth is far colder than that enjoyed now. The norm is Ice Age. Cool the
climate just a little, and a feedback effect drops the temperature further:
the Arctic snowfields creep further south and, because snow reflects away
more sunlight than bare ground, the temperature drops lower, more snow
falls, and on it goes.

Metaphorically, the global climate is similar to a cliff edge, next to which
a drunk is staggering. One step in the wrong direction and over he goes.
Although we'd all like things to remain the same, the reality is that
nothing, most especially the weather, is constant. Coolings seem to be
rapid, and cause disastrous downfalls of civilisation. But we can cope with
slow upward trends in temperature. Our mantra should be slow change good,
fast change bad.

Given that we cannot stop the occurrence of random steps toward the
precipice, what we need to do is arrange for our drunkard to be a safe
distance from the cliff edge. That is why global warming is a good thing. In
fact, life on Earth owes its existence to the greenhouse effect. This became
clear from investigations of other planets. It was by trying to understand
why Venus has such a high surface-temperature (close to 500 C) that we
learned how the terrestrial atmosphere keeps us warm, and realised that
elevated levels of carbon dioxide from the burning of fossil fuels must
surely push Earth's temperature up.

That our planet is subject to the greenhouse effect is not in doubt. The
natural action of the atmosphere elevates the global temperature by almost
40 degrees. The moon is at the same distance from the sun as us, but much
colder because it is airless.

When scientists debate the possibility of life on planets orbiting distant
stars, they may ruminate on the "Goldilocks problem". The global
temperature, like the porridge, must be "just right". But what is the
"right" terrestrial temperature from the perspective of the development of
civilisation?

That there are substantial drawbacks to global warming is unarguable.
Certain low-lying areas such as Bangladesh and various Pacific islands may
well be flooded. It will be the responsibility of the developed nations,
which produce most of the carbon dioxide emissions, to find ways to assist
those people most affected. But it is not only the developing world that
will be inundated. For example, most of Florida, rather than just the
Everglades, may become a swamp. In 100 years' time Miami may be submerged,
but a century ago there was almost nothing there. Such change - slow change,
on the scale of the human lifetime - causing the shifting of peoples has
been a continuing feature of history.

In Britain the coastlines have never been constant: as Beachy Head erodes,
it produces shingle that banks up to the east. The place where William the
Conqueror landed in 1066 is now inland. Status quo is the exception, not the
norm. For the human utility of the planet as a whole, some regions may need
to be abandoned, while new zones of habitability will become available as
planet Earth warms slightly. It is a natural function of humankind to move
on, and search for new opportunities and horizons.

Global warming, then, is great because it protects us from the unpredictable
big freeze that would be far, far worse.

Duncan Steel is reader in space technology at the Joule Physics
Laboratory, University of Salford.


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