From: Amara Graps (amara@amara.com)
Date: Thu Dec 19 2002 - 14:53:19 MST
(Panspermia is taken more seriously these days)
Extracted from my post to extropians list August 8, 2002
with subject: "A Short Report of Asteroids, Comets, Meteors,
Dust and Culture in Potsdam and Bär-lin"
"In the last year, at this meeting and at several earlier meetings, I
have noticed presentations about different aspects of Hoyle's panspermia
idea. I know that on this list I've been rather negative about the
theory because it has carried the 'kook factor' for more than 20 years.
That 'kook factor' seems to be fading some as more and more planetary
scientists are taking parts of the idea seriously, testing the ideas in
the lab if they can. I also noticed that a relatively new book:
_Astrobiolgy: The Quest for the Conditions of Life_, edited by Horneck
and Baumstark-Khan, Springer-Verlag, 2002 has several chapters
addressing the topic, describing relatively new results from lab
experiments.
At the ACM, the most relevant paper I saw addressing the panspermia idea
was from a colleague from Kent (UK), Mark, Burchell, who gave a poster
presentation of the rate of bacteria surviving hypervelocity dust
impacts in the laboratory. In Burchell's abstract, he said that recent
attempts to quantify the probability of life naturally migrating through
space is to break down the migration into discrete steps: ejection from
the planet, survival in space, etc. and to find an independent
probabilty for each step, then to multiply these terms in order to
arrive at an overall probability of panspermia occurring. His particular
lab experiment was to use a light gas gun firing projectiles doped with
bacteria impacting on target materials. He told me that at impacts of
>7 km/sec: nothing lives, at 5 km/sec some live, and at 1 k/-sec, all
bacteria live. He has some resent papers (published as well as just
submitted) about this topic."
--------------------------------
Gerda Horneck
paper 1:
"Bacterial Spores Survive Simulated Meteorite Impact"
http://www.strahlenbiologie.dlr.de/pdf/impact-icarus.pdf
paper 2:
Horneck G, Rettberg P, Reitz G, Wehner J, Eschweiler U, Strauch K,
Panitz C, Starke V, Baumstark-Khan C (2001) Protection of bacterial
spores in space, a contribution to the discussion on Panspermia,
Orig.of Life Evol. Biosphere 31, 527-547.
http://www.strahlenbiologie.dlr.de/pdf/OLEB.pdf
paper 3:
Mileikowsky, C., Cucinotta, F., Wilson, J.W., Gladman, B., Horneck,
G., Lindegren, L., Melosh, J., Rickman, H., Valtonen, M. and Zheng,
J.Q., 2000, Natural Transfer of Viable Mlicrobes In Space,Part 1:
From Mars to Earth and Earth to Mars, Icarus, 145, 391-427.
http://www.strahlenbiologie.dlr.de/pdf/viable%20transfer-icarus.pdf
Her European Geophysical Society Abstract (Nice, France 2002)
www.copernicus.org/EGS/egsga/nice00/ programme/abstracts/aai0441.pdf
Her home page:
http://www.strahlenbiologie.dlr.de/mitarbeiter/horneck.html
The book of which she was coeditor:
_Astrobiology: the Quest for the Conditions of Life_ (Springer, 2001)
http://www.amazon.com/exec/obidos/tg/detail/-/3540421017/103-3108912-1752665?vi=glance
with her chapter 4: "Viable Transfer of Microorganisms in the Solar
System and Beyond (with 5 coauthors)"
4.1 Scenario of Interplanetary Transfer of Life Within the Solar System
4.2 Survival of the Escape Process
4.3 Survival of the Interplanetary Transfer Phase
4.3.1 Space Environment of Interest
4.3.2 Approaches to Sutydying the Biological Effects of Space
4.3.3 Biological Effects of the Vacuum of Space
4.3.4 Biological Effects of the Galactic Cosmic Radiation
4.3.5 Biological Effects of Extraterrestrial Solar UV Radiation
4.3.6 Bacterial Survival During Long-Term Dormancy
4.3.7 Combined Effects of the Complex Matrix of Space Parameters
4.4 Survival of the Landing Process
4.5 Conclusions: On the Likelihood of Interplanetary Transfer of Life
as a Mode of Distribution of Life Throughout the Solar System
4.6 Outlook: On the Likelihood of Transport of Viable Microorganisms
Between Solar Systems
4.7 References
--------------------------------
Mark Burchell
http://berlinadmin.dlr.de/SGF/acm2002/abstracts/pshort/13-13p.pdf
13-13p Poster "Panspermia: Bacteria Survive Hypervelocity Impacts
in the Laboratory"
http://www.ukc.ac.uk/bio/bunch/Research/pr.htm?file=survival.htm
Survivability of bacteria in hypervelocity impacts
One of the biggest questions that science is attempting answer at
present is whether life exists elsewhere in the solar system and
if it does, is it possible that life forms can move between
planets? Currently the focus is on the planet Mars. There are
several reasons for this, but most important is the belief
(supported by the scientific evidence available) that at an early
stage of its existence Mars had environmental conditions similar
to that found on Earth. Microorganisms found on Earth have been
shown to be remarkably resilient to extremes of temperature, pH,
nutrient deprivation and desiccation. There is plenty of evidence
now available that microorganisms can exist for many years in a
desiccated state (at least several millennia) which perhaps could
allow them to survive transit between planets on or in meteorites.
We are currently investigating one aspect of this hypothesis. One
possibility is that transfer could take place after microbes are
ejected from the surface of a planet following collision with
other bodies such as meteorites, asteroids or comets. This would
be followed after some time (several millennia) by a collision
between the material ejected from one planet and the surface of
another. Calculations indicate that the energy released during
such impacts although large could nevertheless allow the survival
of microbes in material fairly close to the impact point.
Using a gas gun was possible to accelerate microbes up to
velocities similar to that which occurs during a typical meteorite
impact with the Earth. We have shown that rhodococci (a
particularly difficult to damage bacterium) can survive such
impacts. We are currently investigating the effect that the
physiological state of such microbes affects their ability to
survive such events and what biochemical damage occurs.
Burchell, M.J., Mann, J., Bunch, A. W. and Brandao, P.F.B. (2001)
Survivability of bacteria in hypervelocity impact. Icarus 154
545-547
Burchell, M.J., Shrine, N.R.G., Bunch, A.W. and Zarnecki, J.C.
(2000) Exobiology: Laboratory tests of the impact related aspects
of Panspermia. In Impacts and Early Earth (I Gilmour and C.
Koeberl, Eds), pp 1-26. Springer-Verlag, Berlin.
-- through December 2002: Max-Planck-Institut für Kernphysik, Cosmic Dust Group, Heidelberg, Deutschland from January 2003: Consiglio Nazionale delle Ricerche, Istituto di Fisica dello Spazio Interplanetario, Roma, Italia
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