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ToSeek
2005-May-31, 04:13 PM
Traces of Stowaway Algae Could Survive on Mars, Study Finds (http://www.spaceref.com/news/viewpr.html?pid=16978)


Some hardy Earth microbes could survive long enough on Mars to complicate the search for alien life, according to a new study co-authored by University of Florida researchers.

Though scientists looking for life on Mars worry about contamination from stowaway spores clinging to spacecraft, the inhospitable Martian environment is actually an effective sterilizing agent: The intense ultraviolet rays that bombard the Martian surface are quickly fatal to most Earth microbes. However, the new study shows that at least one tough Earth species, a type of blue-green algae called Chroococcidiopsis, could live just long enough to leave a biological trace in the Martian soil - creating a potential false positive.

frogesque
2005-May-31, 06:54 PM
From the same link


"It's the biological Heisenberg principle," Rummel added. "Can we do the studies without contaminating what we're looking at? So we have to have some idea of whether or not Earth life is likely to survive (on other planets)."

An outside possibiliy but could this have been the cause of some of the ambiguous results obtained by the Viking missions?

junkyardfrog
2005-Jun-03, 05:53 AM
We're probably already contaminated Mars.

And even if we didn't do it, Mars probably already had life from Earth that was transferred by debris from a comet or meteorite impact.

Argos
2005-Jun-03, 01:48 PM
False positive? I think that if Earthly life were discovered in Mars, it would still be very cool. :)

crazy4space
2005-Jun-03, 09:34 PM
IIRC the part that we brought back from the Ranger 7 on the moon had a cold virus that had survived in space for 3 or 4 years.

01101001
2005-Jun-03, 10:01 PM
IIRC the part that we brought back from the Ranger 7 on the moon had a cold virus that had survived in space for 3 or 4 years.
Apollo 12, Surveyor 3, Streptococcus bateria inside a camera, about 30 months.

But maybe not:

SpaceDaily article (http://www.spacedaily.com/news/lunar-04zza.html):


Part of the discussion centered on sample handling. The Apollo 12 results were later dismissed as laboratory error, owing to a single non-sterile handling event.

Nonetheless, the principle probably holds:


The longest exposure time of bacteria to the harsh vacuum of space was a Bacillus strain that was revived after six years in a controlled biological experiment, so even if the Apollo 12 results are questionable, the ability of bacteria to survive extreme environments is not particularly in question.