No hint of Mars microbes
NASA reported on
19.09.2013Thursday that its Mars rover, Curiosity, which has been trundling
across the red planet for a little more than a year, has deflated hopes that
life could be thriving on Mars today.
The conclusion, published in
the journal Science , comes from the fact that Curiosity has
been looking for methane, a gas that is considered a possible calling card of
microbes, and has so far found none of it.
While the absence of methane
does not entirely preclude the possibility of present-day life on Mars — there
are plenty of microbes, on Earth at least, that do not produce methane — it
does return the idea to the realm of pure speculation without any hopeful data
to back it up.
“You don’t have direct
evidence that there is microbial process going on,”
But NASA scientists are going
strictly by their data. John P. Grotzinger, the project scientist for the
Curiosity mission, would only go so far as to say that the lack of this gas
“does diminish” the possibility of methane-exhaling creatures going about their
business on Mars.
Curiosity made measurements
from Martian spring to late summer, coming up empty for methane.
Scientists have long thought
that Mars, warm and wet in its early years, could have been hospitable for
life, and the new findings do not mean that it was not. But that was about 3
1/2 billion years ago.
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