Mars probe detects (possible) hint of life

Mars probe detects hint of life
Whiff of ammonia is discovered in atmosphere Microbes thought to replenish
the compound
Jul. 16, 2004. 09:20 AM

LONDON—An instrument orbiting Mars may have detected a whiff of life on the Red Planet.

Data from a spectrometer aboard the European Space Agency's Mars Express probe appears to have recorded radiation indicating pungent ammonia gas in Mars' atmosphere, BBC News Online reports.

Since ammonia can survive for only a few hours in the Martian atmosphere before breaking down, it must be constantly replenished from one of two possible sources: active volcanoes — of which none have been found on Mars — or microbes.

"Ammonia could be the key to finding life on Mars," a NASA scientist told the BBC. "There are no known ways for ammonia to be present in the Martian atmosphere that do not involve life."

Ammonia is a compound of nitrogen and hydrogen atoms. Nitrogen is rare in the Mars environment, and researchers say the presence of ammonia may indicate that Martian microbes may be hoarding it.

Spectral evidence of ammonia was seen by the Planetary Fourier Spectrometer [link added] on Mars Express, which has been in orbit around the Red Planet since December.

Scientists have so far only analyzed a fraction of the spectral data the probe has radioed back to Earth.

Researchers say this is because they are still coming to terms with the complexities of the Planetary Fourier Spectrometer as well as coping with some nagging power problems on Mars Express.

Professor Vittorio Formisano, principal investigator for the instrument, is expected to release details of the new findings at an international conference next week in Paris.

The Planetary Fourier Spectrometer is examining radiation on Mars in regions of the spectrum that include the signatures of water and carbon dioxide as well as a high-resolution mode that can detect ammonia and methane.

So far, it has observed a depletion of carbon dioxide and an enrichment of water vapour over some of the large extinct volcanoes on Mars, researchers say.

It has also found methane, another gas with a possible biological origin.

One possibility the scientists had to rule out was that the ammonia came from the air bags of the failed Beagle 2 mission.

Analysis revealed the ammonia's distribution was not consistent with this explanation.

The twin U.S. rovers that landed on Mars in January will be unable to answer the question of the ammonia's origin, as they are designed for geological work.

But future missions could include sensors to analyze the ammonia to determine if it has a biological or volcanic origin. Lava deposited on the surface, or released underground, could produce the gas.

So far, no active volcanic hotspots have been detected on the planet by the many spacecraft currently in orbit.

BBC NEWS ONLINE