[meteorite-list] Did Life Arrive Before the Solar SystemEvenFormed?

From: Marc Fries <m.fries_at_meteoritecentral.com>
Date: Thu May 5 11:08:41 2005
Message-ID: <1200.69.140.92.248.1115305670.squirrel_at_webmail.ciw.edu>

Howdy

   Alright, I need to go point-by-point for this one...

   For the Surveyor 3 microbes: I've never heard the story of Pete Conrad
actually seeing any microbes; are you sure about that? I know they
brought back the camera and other parts and swabbed/cultured them, and
were rewarded with a colony of streptococcus from the camera insulation.
The reason that it was never hyped up, or even published officially as far
as I know, is that it could be the result of airborne contamination
-=after=- the camera was returned to Earth. The camera and other parts
were not handled in a sterile fashion, and they shared the Apollo capsule
with the three astronauts for several days on the way back to Earth. They
were handled after landing as well, and basically there is no sure-fire
proof that this very common airborne microbe did not settle on the camera
afterwards or even result from a sneeze by one of the investigators.

   For the tardigrades: yes, they can withstand a lot. BUT, only after
they have been induced into a spore-like state. They are not
technically alive, but rather in a state of dessicated suspension. The
same can be said for spores of many types of organisms. They are
tougher than when they're actively metabolising, but they're still not
bulletproof. I'm not familiar with the Mars Jars experiment, but keep in
mind that we knew much less about the actual conditions on Mars in the
50's than we do today. I'd be interested in seeing a modern
re-creation of that experiment.

Bah humbug yet,
MDF

> Hi,
>
> Just a sort of footnote to my previous post on this topic. I forgot
> the most
> obvious example of critters in space.
> On April 20, 1967, the Surveyor 3 spacecraft landed on the moon.
> Unknown to us,
> it was carrying some uninvited passengers. When Surveyor 3 was being
prepared for
> launch, somebody apparently coughed on it, and a colony of a common
bacteria,
> Streptococcus mitis, was established on a piece of foam insulation that
covered one
> of Surveyor's circuit boards.
> The bacteria was discovered in 1969 when Apollo 12 astronauts Pete
> Conrad and
> Alan Bean visited the wreck of Surveyor and saw something odd growing on
the
> insulation and brought back a piece of it. The bacteria had struggled
along,
> multiplying and growing for a while before they went dormant and were
freeze-dried.
> Once back on Earth, they were revived in a normal agar culture and
started
> growing
> again, while waiting for their chance to get back into a warm wet human
throat and
> give it a cough...
> For someone whose natural habitat was that warm wet human throat,
I'd
> say they
> handled life in a vacuum with a temperature range of +300 degrees C. to
-250 degrees
> C. every month pretty well.
> I also remember experiments done in the 1950's in which tiny
creatures
> called
> Tardigrades (also known as "water bears") were put into Mars Jars,
meaning
> simulations of the Martian evironment kept at the correct Martian
temperatures,
> pressures, atmospheres, near-waterlessness, and so forth. They thrived and
> multiplied (although more slowly than on Earth). Although Tardigrades
are
> tiny
> (about 200 microns long!), they like us are complex multicellular
organisms with
> feet, guts, heads, eyes, and lots of other movable parts. (Although,
they
> don't
> have jaws because they have evolved a specialized "spear mouth" that
doesn't need a
> jaw -- they don't bite; they stab!)
> I quote: "Some tardigrades can survive in temperatures as low as
> minus 200
> degrees Celsius (minus 328 F). Others can survive temperatures as high
as
> 151
> degrees C (304 F). Tardigrades can survive the process of freezing or
thawing, as
> well as changes in salinity, extreme vacuum pressure conditions, and a
lack of
> oxygen. Tardigrades also are resistant to levels of X-ray radiation that
are
> hundreds of times more lethal to humans and other organisms. This
resilience stems
> from the tardigrade's ability to survive without water."
> The quote is from NASA's ASTROBIOLOGY magazine, which had a nice
> article about
> the "water bears" (with pictures). They look more like Gummi Bears,
with
> the same
> silly faces...
> <http://www.astrobio.net/cgi-bin/h2p.cgi?sid=261&ext=.pdf>
> Now, what would happen if you snuck a tiny little capsule with about
> 100,000,000,000 Tardigrades onto the next Mars probe scheduled to land
on
> the
> surface? Instant Martians? I love a good experiment...
>
>
> Sterling K. Webb
>
>
>
>

-- 
Marc Fries
Postdoctoral Research Associate
Carnegie Institution of Washington
Geophysical Laboratory
5251 Broad Branch Rd. NW
Washington, DC 20015
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FAX: 202 478 8901
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Received on Thu 05 May 2005 11:07:50 AM PDT