From: LARRY KLAES (ljk4@msn.com)
Date: Fri Nov 01 2002 - 11:18:39 PST
BIOLOGICAL PROCESSES IN IMPACT CRATERS
>From Charles Cockell <csco@bas.ac.uk>
BIOLOGICAL PROCESSES IN IMPACT CRATERS
March 29-April 1, 2003, Cambridge, UK
The second announcement and registration materials are now available on the
ESF website : http://pssri.open.ac.uk/ESF/Main.htm
The workshop, to be held in Cambridge, UK from March 29 to April 1 next year
will examine the ecological characteristics of impact craters and the
biological processes that occur within them. The conference should be of
interest to astrobiologists, impact scientists, geologists and others. As
well as examining patterns of recovery in impact structures, the workshop
will also explore themes such as the formation of hydrothermal vents within
impact structures and the biological consequences.
__________________________
Dr. Charles Cockell,
British Antarctic Survey,
High Cross,
Madingley Road,
Cambridge.
CB3 0ET. UK
Tel : + 44 1223 221560
e-mail : csco@bas.ac.uk
==============
(6) TOWARDS OTHER EARTHS: DARWIN/TPF CONFERENCE 2003
>From Alan Penny <alan.penny@rl.ac.uk>
Dear Benny,
[This is a circular letter to people who signed a round-robin last year to
ESA supporting Exoplanets and Astrobiology.]
Toward Other Earths
Darwin / TPF and the search for extra-solar terrestrial planets
Heidelberg, Germany 22-25 April 2003
http://www.mpia-hd.mpg.de/DARWIN/
The conference "Toward Other Earths" is the first in a series of
multi-disciplinary international meetings designed to provide a forum for
scientists and engineers active in many different areas as well as managers,
representatives of the space agencies and industry working on the Darwin/TPF
mission. The aim of the conference is to exchange information, formulate new
ideas and propose new approaches towards the implementation of a
multi-agency mission with the goal of detecting Earth-like planets orbiting
stars other than our Sun. The primary goal of the Darwin mission (and its
NASA counterpart TPF) is to detect and characterize extrasolar Earth-like
planets orbiting other stars, and to search for signs of life on these
planets. This conference will focus almost exclusively on this goal.
A secondary goal of Darwin is to provide imaging of astrophysical objects in
the mid-infrared at unprecedented angular scales.
Regards, Alan Penny
===========
(7) LIFE AMONG THE STARS
>From Sky and Space, Oct/Nov 2002
www.skyandspace.com.au
More than two hundred scientists converged on Hamilton Island,
Queensland, recently for a conference that was out of this world.
Michael Paine reports...
Every few years the International Astronomy Union holds a symposium on
astrobiology - the study of life in outer space. This year the conference,
called Bioastronomy 2002: Life Among the Stars, was held on Hamilton Island,
adjacent to the Great Barrier Reef. Not surprisingly many scientists made an
extra effort to attend a conference at such a glorious location. There were
70 speakers from 16 countries and well over two hundred participants.
The wide range of topics covered included:
· space chemistry,
· the formation of planets,
· planetary atmospheres and surfaces,
· the search for planets around other stars,
· origins of life on Earth,
· the search for primitive life elsewhere in the solar system,
· obstacles to the evolution of intelligent life; and
· the search for extraterrestrial intelligence (SETI).
To non-scientists (like myself) some of the titles appeared a little
daunting but it was pleasing to see that most speakers addressed the wider
audience. Australian astronomer Chris Tinney set the standard by asking
participants to hold up a yellow card if he lapsed into gobbledegook. Those
who dared to do this were rewarded with a chocolate frog. Later in the
conference it was intriguing to see a few yellow cards raised but the
speakers were oblivious to their purpose.
Here is a taster for the smorgasbord of topics covered by the
conference.
Harrison (Jack) Schmitt, Apollo 17 astronaut and the only scientist to walk
on the Moon, opened the conference with a talk called "Life among the
craters". He showed how the rocks returned from the Apollo 17 landing site
confirmed cataclysmic impacts on Earth nearly four billions years ago. Later
he expressed scepticism about the giant impact hypothesis for formation of
the Moon - that is, that a Mars-size planet collided with the Earth and the
debris from the impact formed our Moon. Also comparing the surface of the
Moon with Mars and Earth, he suggested there was strong evidence for a major
ocean on Mars about three billion years ago.
Barry Blumberg from the NASA Astrobiology Institute (NAI) described how
educational outreach is a major aim of NAI. Astrobiology covers many
disciplines of science and humanities and there are great opportunities for
incorporating it into educational programs. The Australian Centre for
Astrobiology at Macquarie University is an affiliate of NAI. Blumberg had a
refreshing approach to the funding of scientific research. He said that NAI
funding allows for changes in direction of projects because 'scientists
never do what they said they were going to do' when applying for funds.
Planets
Australian Chris Tinney gave a lively introduction to the search for
extra-solar planets. He described the very poor odds of detecting an
Earth-like planet with current techniques but was optimistic that the
necessary technology would soon be developed - particularly with proposed
space-based missions. He described the Kepler space mission that will look
for Earth-like planets at 'crazy precisions'. The proposed European Space
Agency Darwin mission will use infrared
interferometry but has some technical challenges. Similarly the NASA
Terrestrial Planet Finder (TPF) mission is seen as ambitious. He cautions
that TPF will target 150 nearby stars but if only 1 in 100 stars has an
Earth-like planet then it is possible there is nothing for TPF to find.
One technique that holds promise is 'gravitational microlensing', where a
star with a planet passes in front of another star and the bending of light
rays by gravity causes a brief brightening of the background star. This is
a very infrequent event and it requires exceptional luck. Several groups are
carrying out highly automated search for these events by piggy-backing on
other (Earth-based) telescope projects. In some ways, the automated
techniques are similar to those being used to search for Near Earth
Asteroids. Later Penny Sackett from Mt Stromolo
Observatory described Australian involvement in microlensing observations.
SETI
Jill Tarter from the SETI Institute pointed out that SETI is looking for
extraterrestrial technology - particularly information technology. There may
be signals that are intended to be intercepted by emerging civilisations or
unintended noise like the radio waves that are now radiating in a sphere
away from the Earth - ''I Love Lucy' is broadcasting our intelligence!'
SETI, she says, is founded on the scientific principle of repeatability.
Other researchers must be able to independently confirm any discoveries.
She also suggested that if ET wants to be discovered then it would make
sense to send a signal that was similar to a natural process and so it would
be found during the normal course of science. This view may have been partly
swayed by bitter experience in the USA, where in the early 1990s Congress
short-sightedly banned NASA from spending any funds on SETI. SETI is now
privately funded in the US and piggybacks on other radio-telescope projects.
The enormous success of the SETI@home computing project has proved that
Congress was dead wrong about public support for SETI.
Tarter said that the prospects for 'optical SETI' had recently been boosted
by developments with Stars Wars Technology (US missile defence). Very short
intense bursts of light could now be emitted and methods of detecting these
bursts (possibly from ET) are being developed. In the long term she sees
omni-directional detectors as the way to go - a radio 'fly's eye'. This
would create a massive computational task but may be possible in about 15
years. She mentioned Project Argus, a proposal to build 5000 backyard
receivers around the world to create a 'poor man's fly's eye'. Finally, the
Allen Telescope Array is under construction in northern California. 'This
will speed up the search by a factor of 100' she said.
Mars and Europa
Malcolm Walter, the head of the Australian Centre for Astrobiology, outlined
the methods of searching for evidence of microbes on Mars, based on his
research in Central Australia. He has studied ancient hydrothermal systems
that are similar to Yellowstone National Park in the USA. He explained that,
on Earth, these systems are 'full of life' and that the chemicals in the
water make fossilisation extremely efficient. In studying these ancient
Earth systems he is developing techniques that could be used to examine
similar systems on Mars. He said he would like to go the Daar Vallis area of
Mars because there are indications of hydrothermal deposits.
Chris Chyba from the SETI Institute in California described the search for
life in the Solar System. He was excited about the recent evidence of 'a
great deal of water on Mars' - frozen just under the harsh surface - and the
hundreds of ancient features that appear to show erosion by flowing water.
He is looking forward to the landing of the Beagle 2 spacecraft on Mars
because that could resolve many of the tantalising unanswered questions
resulting from the Viking Landers in the mid 1970s. He also pointed out that
scientists were still debating a definition of life.
Chyba then turned to Europa. By precisely tracking spacecraft such as
Galileo and Voyager, scientists have determined that the outer 100km of the
surface of Europa has the density of water and the simplest explanation is
that it is salty water. He explained that tidal forces from the giant planet
Jupiter should be sufficient to maintain liquid water below Europa's ice
crust, which is thought to be several kilometres thick. Based on the count
of impact craters the average age of this crust is no more than 50 million
years... so there must be some unknown processes that are refreshing the
surface. There are signs of recent solidification of water and these might
be the best places to look for life. He said we can learn about the buried
ocean and
possibility of life by studying such sites rather than 'boring through the
ice' (a current NASA proposal).
If there is (or was) life on Europa there are two possible origins. Firstly
it may have arisen independently, say in deep ocean vents. Alternatively it
may have been transferred from Earth, or perhaps Mars, via meteoroids
blasted off the planet by large asteroid impacts (known as 'panspermia' or,
more precisely 'transpermia'). Chyba explained that the icy crust and lack
of atmosphere hindered both mechanisms on Europa - an asteroid or comet
striking the solid ice surface at 20km/s or more would be instantly
vaporised. However, some organic material such as
non-biological amino acids could be expected to reach the surface intact and
find its way to the oceans. Over billions of years this may have provided
sufficient raw material to support the development of life.
During question time it was suggested that Jupiter might have been hotter
billions of years ago (it still radiates more energy than it receives from
the Sun). Chyba said he was not aware of any studies of this mechanism.
Later, over coffee, I discussed this possibility with him. He agreed that a
hotter Jupiter may have resulted in liquid water on the surface of Europa.
This would have generated an atmosphere which, in turn, would have slowed
down fragments of asteroids and comets sufficiently to greatly increase the
chances of intact material reaching the ocean. There is therefore the
exciting possibility that three billion years ago the Earth, Mars and Europa
exchanged life-bearing rocks.
Everett Gibson from NASA was one of the original authors to the
controversial paper that claimed evidence of life in Martian meteorite
ALH84001. Gibson went over the claims and counter-claims, focusing on the
tiny magnetite crystals found deep inside the meteorite. He said that within
the scientific community, six properties of magnetite had been identified in
order to establish that a crystal of magnetite was 'biogenic' (i.e. formed
by a living organism). He claimed that some of
the crystals in ALH84001 met all six properties. In other words, the debate
about ALH84001 is far from over.
Betty Pierazzo from Arizona University has been developing computer models
to simulate the climatic effects of asteroid and comet impacts. She
described her successful modelling of the Chicxulub impact in Mexico 65
million years ago. This is a well studied event associated with the
extinction of the dinosaurs.
Pierazzo then discussed mechanisms for delivery of organic material to the
surface of planets and moons. She said that the smaller slower impacts
delivered the most intact organic material and this 'was not good news for
Europa' with its current surface of ice. Later I discussed
the environmental effects of impacts with her, since I had prepared a poster
paper [co-authored with Benny Peiser] on this topic
[http://www4.tpg.com.au/users/tps-seti/bioastr2002.pdf] and had referred to
her work. To my surprise she said that her work was partially hampered by a
lack of access to the most advanced computing available in the USA...
apparently because she was not born in the USA.
Cosmologist Paul Davies from Macquarie University discussed the possible
role of quantum mechanics in the origin of life. He explained that there was
nothing in classical physics that might 'fast track' the formation of life.
Making the building blocks of life, like amino acids, was straightforward
and widespread in nature. He pointed out, however, that this was a long way
from a self-replicating molecules.
Davies said that when the theory of quantum mechanics was first developed it
was thought that it would eventually explain the origin of life. Fifty years
on and quantum mechanics 'has no direct relevance' to the origin of life.
But there are signs that information theory and quantum computing may
provide some answers. Quantum computing
[http://www4.tpgi.com.au/users/aoaug/qtm_comp.html] harnesses the quirks of
quantum mechanics to provide an exponential improvement in computing power.
He said there was circumstantial evidence that nature uses quantum
computations. There is therefore the possibility that the extraordinary
power of quantum computing resulted in the first self-replicating molecule.
He cautioned, however, that the RNA/DNA on which life is based is a long way
from such a molecule. There is also the major problem of "decoherance",
where the atomic environment interferes with the quantum processes and
destroys the computation. Davies suggested that the
developing fields of biotechnology and nanotechnology might provide some
answers.
There were many other fascinating talks during the week. It was remarkable
to hear from top scientists who tailored their talks to a general science
audience and were evidently delighted to share their exciting discoveries.
c2002 Sky and Space
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