- A strong signal of life on Mars has been detected by
scientists at the US National Aeronautics and Space Admin- istration (Nasa)
and the European Space Agency.
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- Each group has independently discovered tantalising evidence
of methane in the Martian atmosphere. Methane, a waste product of living
organisms on Earth, could also be a by-product of alien microbes living
under the surface of the Red Planet.
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- The detection of methane has been the holy grail of scientists
studying the Martian atmosphere, as its presence could provide unequivocal
proof that there is life beyond Earth.
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- Neither Nasa nor the European Space Agency (ESA) has
publicly announced the findings, but specialists who have seen the data
believe the discovery is genuine - although they are unsure what it means
in terms of confirming the presence of life.
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- The discovery comes weeks after Nasa and ESA announced
new findings relating to the presence of huge bodies of water on Mars which
could have supported life.
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- The European effort is led by Vittorio Formisano, of
the Institute of Physics and Interplanetary Science in Rome, who operates
the methane-detecting spectrometer on board the Mars Express spacecraft
orbiting the planet. "We can identify the presence of methane in the
Martian atmosphere and we've been able to evaluate how much of it there
would be," Professor Formisano said. "Globally, if I average
all the data I have, I can find something of the order of 10 or 10.5 parts
per billion. It's detectable, but only if I average a lot of data."
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- Methane is destroyed by the intense ultraviolet radiation
on Mars because the gas has a relatively short photochemical lifetime of
about 300 years, so if it is present there must be something producing
it continually, Professor Formisano said. "[Its presence] is significant
and very important. If it is present you need a source," he added.
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- The second group to detect signals of methane in the
Martian atmosphere is led by Michael Mumma of Nasa's Goddard Space Flight
Centre in Maryland, who used powerful spectroscopic telescopes based on
Earth.
-
- This team is even believed to have detected variations
in the concentrations of methane, with a peak coming from the ancient Martian
seabed of Meridiani Planum, which is being explored by a Nasa rover.
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- This could indicate a subterranean source of methane
which is pumping out the gas, either due to some residual geological activity
or because of the presence of living organisms producing it as a waste
gas.
-
- Asked whether the continual production of methane is
strong evidence of a biological origin of the gas, Dr Mumma said: "I
think it is, myself personally."
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- He added: "It's difficult to imagine that primordial
methane [from geological activity] would continue outgassing for four billion
years [the age of Mars]. This looks very intriguing."
-
- Both teams of scientists are now busy validating their
results before their respective organisations are prepared to go public
on the implications.
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- © 2004 Independent Digital (UK) Ltd
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- http://news.independent.co.uk/world/science_medical/story.jsp?story=505454
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