METHANE GAS in the Mars atmosphere could indicate the presence of life on the planet, Nasa scientists have said.
Methane is usually a byproduct of microbial organisms on Earth and, at a press conference last night, Nasa said the gas had either biological or geological origins.
Nearly 19,000 tonnes of methane was detected using Earth-based telescopes based in Hawaii, which scanned 90 per cent of the Martian surface for seven years.
The gas was present in the northern hemisphere during the Martian summer and later disappeared, suggesting that it was recently created.
Nasa scientists believe the process could be biological or alternatively created by serpentinisation, which occurs when rocks rich in certain minerals react with water, releasing methane.
Prof Lisa Pratt, director of the Nasa astrobiology lead team, said the space agency needed to change its philosophy from looking for ancient life on Mars to looking for the possibility that life might still exist on the planet.
To date, most scientists have concluded that life on Mars, if it existed at all, occurred in the planet’s first billion years, when it was warmer and wetter than it is now.
She said the methane could be the “exhaled breath of a microbial ecosystem” and was a “very important new piece of information”.
“We simply have to accept the fact that, while we are currently developing a strategy to search for ancient life on Mars, we also need to think in terms of present-day life still holding on in the subsurface.”
However, Prof Pratt cautioned against the assumption the methane was caused by life on Mars.
“As a life scientist, I would love to think it was biology, but we need other lines of evidence before it tips the balance one way or the other.”
