Brussels, 30 Mar 2004
Scientists working with the Mars Express mission have detected methane in the Red Planet's atmosphere, supporting two previous observations of the gas, and leading to speculation that the planet is harbouring life.
The European Space Agency has confirmed that a team led by Vittorio Formisano of the Institute of Physics and Interplanetary Science in Rome, Italy, has detected methane using the Planetary Fourier Spectrometer (PFS) instrument onboard Mars Express.
The discovery supports previous research by a team in the US, that used infrared spectrometers attached to powerful Earth based telescopes to detect methane in 2003. A third group of researchers, also based in the US, is about to present yet more evidence that the gas is present in the Martian atmosphere.
'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.'
Professor Formisano sounded a clear note of caution, saying that, by itself, the PFS instrument they used was not yet good enough to conclusively detect methane.
However, he still described his team's findings as 'significant and very important'. Crucially, methane would have a lifetime of just several hundred years on Mars due to the presence of intense ultraviolet radiation. If the gas does prove to be methane therefore, it would mean that something on Mars is continually producing it.
On Earth, a large proportion of atmospheric methane is the result of bacteria, or even some animals, digesting organic matter. Methane trapped below the Earth's crust since the formation of hydrocarbons can also be released into the atmosphere through geological activity such as volcanoes.
However, some scientists find it hard to believe that Mars could continue to release methane four billion years after its formation. Asked whether the presence of methane is strong evidence of a biological origin, Martian atmospheric expert Dr Michael Mumma said: 'I think it is, myself personally.'
The next challenge for Professor Formisano and his team is to try to determine variations in the concentrations of methane in the Martian atmosphere, and in doing so, to narrow down the possible sources of the gas.
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