As the Huygens probe descended through Titan's
atmosphere, it sent data on the chemical make-up of the atmosphere.
The data stream is being analyzed to break out readings on the
hydrogen and acetylene concentrations.
New Scientist reports in
Has Huygens found life on Titan? that Chris McKay and Heather
Smith, of NASA's Ames Research Center in Moffet Field, California
and the International Space University in Strasbourg, France,
respectively, 'have worked out the likely diet of such organisms on
Titan.'
McKay and Smith calculate that if
methanogens are thriving on Titan, their breathing would deplete
hydrogen levels near the surface to one-thousandth that of the rest
of the atmosphere. Detecting this difference would be striking
evidence for life, because no known non-biological process on Titan
could affect hydrogen concentrations as much. ...
It will take time to analyse the raw data, partly because
hydrogen's signal will have to be separated from those of other
molecules. "Eventually, I hope, we will have numbers for at least
upper limits for hydrogen," says Hasso Niemann of Goddard Space
Flight Center in Maryland, principal investigator of the GCMS [the
instrument which recorded atmosphereic chemical composition on
descent and landing].
Acetylene could be easier to analyse, McKay says, and it too might
betray life. "I would guess that there would be a similar fall-off
of acetylene if the microbes are eating it." The work is to be
published in the journal Icarus.
No timeframe is given for when results will appear.