Aeronautics Industry

Hurt · Guest

I'm not sure if it's my own informational feedback but the great
global unconsciousness has recently on several occasions implied that
there may be life on Saturn's moon Titan. Further details requested.

http://www.newscientist.com/article.ns?id=dn7716

IF LIFE exists on Titan, Saturn's biggest moon, we could soon know
about it - as long as it's the methane-spewing variety. The chemical
signature of microbial life could be hidden in readings taken by the
European Space Agency's Huygens probe when it landed on Titan in
January.

Titan's atmosphere is about 5 per cent methane, and Chris McKay of
NASA's Ames Research Center in Moffet Field, California, thinks that
some of it could be coming from methanogens, or methane-producing
microbes. Now he and Heather Smith of the International Space
University in Strasbourg, France, have worked out the likely diet of
such organisms on Titan.

They think the microbes would breathe hydrogen rather than oxygen, and
eat organic molecules drifting down from the upper atmosphere. They
considered three available substances: acetylene, ethane and more
complex organic gunk known as tholins. Ethane and tholins turn out to
provide little more than the minimum energy requirements of
methanogenic bacteria on Earth. The more tempting high-calorie option
is acetylene, yielding six times as much energy per mole as either
ethane or tholins.

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.

One hope for testing their idea rests with the data from an instrument
on Huygens called the GCMS, which recorded Titan's chemical make-up as
the probe descended. 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.

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.

http://huygensgcms.gsfc.nasa.gov/gcms_overview.htm
http://ael.gsfc.nasa.gov/saturnGCMSMass.shtml