[meteorite-list] Dig Deeply to Seek Life on Mars

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Mon, 29 Jan 2007 20:47:29 -0600
Message-ID: <006601c74418$fc177c90$7ce68c46_at_ATARIENGINE>

Hi,

    At the risk of sounding off too much, when
I read this, only one thought comes to mind:
HOGWASH!

    The defining characteristic of Life is that it
adapts to its environment. Whatever lousy
environment it gets stuck with, it makes the
best of it. There is a micro-organism on Earth
called Deinococcus radiodurans which would
laugh itself silly at this "research."

    While a dose of 10 Gy is sufficient to kill a
human, and a dose of 60 Gy is sufficient to kill
all cells in a culture of E. coli, D. radiodurans is
capable of withstanding an instantaneous dose
of up to 5,000 Gy with no loss of viability, and
an instantaneous dose of up to 15,000 Gy with
37% viability. It can ignores the inconveniences
of heat, cold, dehydration, vacuum, and acid. It
has no trouble eating mercury or heavy metals,
even radioactive ones. It can become a nuisance
in nuclear reactors because it likes to colonize
the core, where all that nice toasty radiation is.

    It's been suggested that C. radiodurans may
be a Martian microbe brought to Earth by a meteorite:
http://www.liebertonline.com/doi/pdfplus/10.1089/ast.2006.6.911?cookieSet=1

    Further, in experiments carried out years ago
to compare the radioresistence of D. radiodurans
with common microbes like E. coli, researchers
discovered that, while E. coli died off at horrendous
rates from radiation as compared with D. radiodurans,
IF you kept using the SAME cultures of E. coli for
the tests over and over again, the E. crowd gained
the ability to endure almost as much radiation as
the tough guys. (And 20 years after those experiments
ended, those E. coli, retained their radioresistence,)
They were evolving the same skill set as D. radiodurans.
THAT is what Life does.

    So I say again, HOGWASH! If D. radiodurans
comes from Mars, then the Martians are doing just
fine, and if D. radiodurans is Earthly, why then,
the Martian microbes (if there are any) can learn
to do the same, just like the hapless E. coli who
lost their nice warm dungy environment and had to
learn to thumb their noses at X-rays. The Martians
should get up off their butts and get to evolving!

    THAT is what Life does. If there is life on Mars,
it will not be restricted to living a stodgy protected
life in some warm aquifer for 4 billion years and
doing nothing else with its existence. There are
many Earthly organisms living in cozy protected
environmental nooks, complete with flat-screen
TV and beer in the fridge, while at the same time
there are multitudes of lifeforms living in every
conceivable condition: boiling sulfuric springs a
half mile down in the ocean, on ice floes in the
Arctic, flying in the near stratosphere --- well,
there is no niche for Life that is not filled.

    IF there really were Life on Mars, it would be
everywhere. It wouldn't be solely microbial, either.
Tough, durable multi-celled creatures abound:
http://en.wikipedia.org/wiki/Tardigrada

    If you're not familiar with tardigrades, take a
look. They are related to arthropods; there are
1000 species; the largest are almost 2 mm long.
They can live for ten years after being freeze-dried.
They can survive being heated for a few minutes
to 151?C or being chilled for days at -200?C, or
for a few minutes at -272?C. (1? warmer than
absolute zero). They can withstand 5,700 grays
or 570,000 rads of x-ray radiation. (Five grays or
500 rads would be fatal to a human). They can
withstand a vacuum and also very high pressures,
many times greater than atmospheric pressure.
They can almost certainly live for some time
in space. Can you do that?

    Why are Tardigrades tiny on Earth? Their
name tells the tale; they're "slow walkers."
If you can't move fast enough to keep from
being eaten, it behooves your grandchildren
to stay small, a smart strategy. If they had
no natural predators, I have no doubt there
would be killer Tardigrades the size of trucks.
(Tardigrades eat plants and bacteria, but some
are predatory on smaller Tradigrades.)

    In 1956, there was a series of experiments
growing Tardigrades in "Mars Jars," closed
environments designed to emulate what we
then thought Mars was like. The Tardigrades
took to the Mars Jars like they were going to
Cozumel. Admittedly, our 1956 idea of Mars
is a little gentler than the real Mars, but I suspect
that Earthly Tardigrades could adapt to the
real Mars. (Better not put any on the next
probe!)

    While there is a kind of appeal in the idea
of the commonality of "low" life, microbial,
archaic, primitive life being widespread, across
the worlds everywhere, an Saganesque appeal
to which we are very susceptible, the truth is...
That's not the way Life works

    Let's say the "researchers" are right about
the deep warm aquifer being the ideal spot
for Life. Life thrives there. It get crowded. As a
result, some poor slobs of a life get pushed out
to the very edges of the aquifer where things
are far from ideal, the aquiferian slums. What
do they do? They adapt. They get good at
handling the new environment. They thrive,
and some life gets pushed to a further, drier,
colder, more radiative edge of the aquifer.
Again, they adapt. They get good at handling
THAT new environment.

    Finally, some life gets pushed right up out
of the ground onto Oh No! NOT... The Surface!
Ya know, there's a lot of elbow room up here.
And with all this light, I can use my photosensitive
spots to navigate. And, look! Here's something
to eat! They adapt. THAT is how Life works.

    Mars has had four billion years, just like we
have. IF Mars had ANY life, it would not have
gone for four billion years without changing, without
adapting, without the fundamental and deadly
necessity of evolution having been at work.
Evolution is not a choice. You can't say "No,
thank you, I'll just stay here in my nice cozy
aquifer and multiply immortally my primitive
genome just the way it is. No changes for me,
please." It's not an option.

    So, the Principal Life Detection Instrument
Package on the Mars Exploration SUV is a video
camera on every corner to see if any Thing comes
up to take a bite out of your (possibly edible) butt.
How are they going to know if you're edible without
having a nip?

    And, if that doesn't happen, then there won't
be any microbes in the dirt, primitive organisms in
the rocks and nobody living the Good Aquiferian
Life for four billion years.


Sterling K. Webb
-------------------------------------------------------------
----- Original Message -----
From: "Ron Baalke" baalke at zagami.jpl.nasa.gov
To: "Meteorite Mailing List" meteorite-list at meteoritecentral.com
Sent: Monday, January 29, 2007 1:14 PM
Subject: [meteorite-list] Dig Deeply to Seek Life on Mars



<http://www.agu.org/sci_soc/prrl/2007-03.html>

Dig deeply to seek life on Mars
AGU Release No. 07-03
29 January 2007

American Geophysical Union
University College London
Joint Release

AGU Contact: Peter Weiss
Public Information Manager
Phone: +1-202-777-7507
E-mail: pweiss at agu.org

UCL Contact: Alexandra Brew
Phone: +44-(0)20-7679-9726
E-mail: a.brew at ucl.ac.uk

WASHINGTON - Probes seeking life on Mars must dig deeply into young
craters, gullies, or recently exposed ice to have a chance of finding
any living cells that were not annihilated by radiation, researchers
report in a new study. One promising place to look for them is within
the ice at Elysium, site of a recently discovered frozen sea, they say.

Current probes designed to find life on Mars cannot drill deeply enough
to find living cells that may exist well below the surface, according to
the study. Although these drills may yet find signs that life once
existed on Mars, the researchers say, cellular life could not survive
incoming radiation within several meters [yards] of the surface. This
puts any living cells beyond the reach of today??Ts best drills.

The study, to be published 30 January in the journal Geophysical
Research Letters, maps cosmic radiation levels at various depths, taking
into account surface conditions in various areas of Mars. The lead
author, Lewis Dartnell of University College London, said: "Finding
hints that life once existed - proteins, DNA fragments, or fossils - would
be a major discovery in itself, but the Holy Grail for astrobiologists
is finding a living cell that we can warm up, feed nutrients, and
reawaken for studying."

"Finding life on Mars depends on liquid water surfacing on Mars,"
Dartnell added, "but the last time liquid water was widespread on Mars
was billions of years ago. Even the hardiest cells we know of could not
possibly survive the cosmic radiation levels near the surface of Mars
for that long."

Unlike Earth, Mars is not protected by a global magnetic field or thick
atmosphere, and for billions of years it has been open to radiation from
space. The researchers developed a radiation dose model and quantified
variations in solar and galactic radiation that penetrates the thin
Martian atmosphere down to the surface and underground. They tested
three surface soil scenarios and calculated particle energies and
radiation doses both on the surface and at various depths underground,
allowing them to estimate the survival times of any cells.

The team found that the best places to look for living cells on Mars
would be within the ice at Elysium, because the frozen sea is relatively
recent - it is thought to have surfaced in the last five million years - and
so has been exposed to radiation for a relatively short period of time.
Even here, though, any surviving cells would be out of the reach of
current drills. Other ideal sites include young craters, because the
recently impacted surface has been exposed to less radiation, and
gullies recently discovered in the sides of craters. Those channels may
have flowed with water in the last five years and brought cells to the
surface from deep underground.

The study was funded by the United Kingdom's Engineering and Physical
Sciences Research Council (EPSRC), the Swiss National Science
Foundation, and the Swiss State Secretariat for Education and Research.

------------------------------------------------------------------------

Notes for Journalists

Journalists and public information officers of educational and
scientific institutions (only) can receive a PDF copy of this paper (a
pre-publication copy subject to final editing of any article listed as
"in press") by sending a message to Jonathan Lifland at jlifland at agu.org .
Please provide your name, the name of your
publication, and your phone number.

Members of the public can read the abstract of any published paper by
clicking on the doi link in the source section, at the end of the
highlight. The full scientific article is available for purchase through
a link in the abstract.

The paper and this press release are not under embargo.

      Title:

"Modelling the surface and subsurface Martian radiation environment:
Implications for astrobiology"


      Authors:

Lewis Dartnell:
    Centre for Mathematics and Physics in the Life Sciences and
    Experimental Biology (CoMPLEX), University College London, London,
    United Kingdom;

L. Desorgher:
Physikalisches Institut, University of Bern, Bern, Switzerland;J. M. Ward:
    Department of Biochemistry and Molecular Biology, University College
    London, London, United Kingdom;

A. J. Coates:
    Mullard Space Science Laboratory, University College London,
    Dorking,United Kingdom.


      Citation:

Dartnell, L. R., L. Desorgher, J. M. Ward, and A. J. Coates (2007),
Modelling the surface and subsurface Martian radiation environment:
Implications for astrobiology, Geophys. Res. Lett., 34, L02207,
doi:10.1029/2006GL027494, in press.


Contact information for authors:

    * Lewis Dartnell: +44-(0)7799-532-842 (mobile phone; omit "0" if
      calling from outside the United Kingdom) or l.dartnell at ucl.ac.uk

AGU is a worldwide scientific community that advances, through unselfish
cooperation in research, the understanding of Earth and space for the
benefit of humanity.

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Received on Mon 29 Jan 2007 09:47:29 PM PST