THE SHOCKING possibility of finding life on Mars has taken a step closer. New research published this morning indicates that methane found in the Martian atmosphere can only be there because of something happening on the planet’s surface.
The presence of methane could indicate biological processes or volcanic activity but some scientists had suggested methane could also be delivered by incoming meteorites.
However, this possibility has now been ruled out by scientists from Imperial College London who say the methane must come from something happening at the surface.
They conducted experiments showing that meteorites falling through the atmosphere could produce about 10kg of methane each year.
However, this was well below the 100-300 tonnes needed to maintain the current levels being measured, the scientists write this morning in the journal Earth and Planetary Science Letters.
This now leaves just two likely sources, the Imperial researchers indicate: either it comes from volcanic activity or it is produced by microbes living at the surface.
The implications of this are enormous, suggested Kevin Nolan, physics lecturer at the Institute of Technology Tallaght and author of an internationally sold book, Mars, A Cosmic Stepping Stone.
“The methane being generated on Mars is indigenous to Mars,” he said yesterday. “It is a big deal.”
The methane seen there today must also have a fairly recent origin, he said. The sun breaks down methane very quickly and changes it into other chemicals.
“It doesn’t last for more than two years in the Martian atmosphere,” Mr Nolan said. “If methane is there, it is being produced right now.”
Geological activity could produce “huge amounts of methane” in a very simple process, he said. Hot water flowing over solidified lava in Mars’ carbon dioxide atmosphere could do this, he said.
There were few signs of recent volcanic activity, however, with the last major events taking place several million years ago, Mr Nolan said.
At best, there were some signs of activity several hundred thousand years ago but any resultant methane would have been destroyed long ago.
This leaves the tantalising possibility that living, multiplying, dining microbes currently occupying the Martian biosphere are the source of the methane.
“This would be a significant discovery on a biological but also a philosophical basis,” Mr Nolan suggested. It could tell us about the origins of life and also about its cosmic abundance and “provide insights into the nature of life itself”.
This is why the world's planetary scientists were shocked in 2004 when the European Space Agency's Mars Expressdiscovered traces of methane above the Red Planet.
Ground-based observatories in Hawaii have since identified “hot spots” of methane and US and Europe scientists plan a joint satellite mission for 2018 to search for the source of the methane.
“This will affect all future explorations of Mars,” Mr Nolan said. It will give scientists a target at the surface to go dig for the possible first confirmation of life found away from Earth.
Should geological reasons be found responsible it was still very significant, he added. “Even if it is hydrothermal, this is also a highly exciting discovery.”