Peter N Spotts

Hopes of finding evidence that organic life gained a toehold on Mars appear to be brightening. To be sure, no one yet has uncovered direct evidence for life there. An experiment designed to look for it, the European Space Agency’s Beagle 2 Lander, failed on arrival at Mars in December 2003. But results from US and European orbiters circling the Red Planet and the discovery of another new species of ice-happy microbes on Earth leave many researchers convinced that it is just a matter of time before they come up with the “smoking guns.”

On Friday, the European Space Agency wrapped up a weeklong meeting in Noordwijk, Netherlands, focusing on the first year’s results from its Mars Express orbiter. Planetary scientists reported evidence for volcanic eruptions within the planet’s recent past. Others have spotted what they interpret as a large, dust- covered frozen sea. Still others cite the presence of methane and formaldehyde in the Martian atmosphere as evidence for current biological activity.

“Hints of life on Mars are getting stronger,” notes Vittorio Formisano, whose research group detected the two compounds in the planet’s tenuous atmosphere using instruments on Mars Express. Indeed, an informal survey of participants at the meeting indicated that 75 per cent of the researchers present agreed that bacteria once lived on Mars. Roughly 25 per cent agreed that bacteria inhabit the planet today.

Meanwhile, a meeting in Houston scheduled for next month will highlight a range of results from Mars Express and from the US Mars Global Surveyor and Mars Odyssey orbiters for near-surface ice and glacial activity in Mars’ recent past.

The evidence for a frozen sea near Mars’ equator comes from Mars Express images analysed by a team led by John Murray, a researcher at the Open University in Milton Keynes, England.

Placed side by side with a picture of Antarctic pack ice, the Mars image looks different only in its signature rust-coloured dust. The researchers say the water that formed the sea probably came from within the crust. They estimate that the floods covered the region somewhere between 2-10 million years ago.

The researchers reckon that the sea is still there. The few craters in the area are very shallow, indicating that once an impactor hit, water quickly refilled the crater. Moreover, the surface surrounding the ice floes is extremely flat, compared with hints of an underlying “sea bottom,” implying a frozen sea. Meanwhile, researchers from Cornell University, NASA’s Johnson Space Centre, and Lockheed-Martin describe a layer of ice some 40 meters thick, thought to be at least 5 million years old. The layer is actively reshaping the surface in a mid- latitude region known as Western Utopia.

These results and others leave researchers champing at the bit for a sample-return mission. Both space agencies are looking at the prospect for launching such missions between 2011 and 2014. NASA’s Dr Hoover notes that colleagues elsewhere claim to have revived bacteria from 100 million-year-old salt crystals, and some varieties “freeze dry” well at liquid-nitrogen temperatures — only to be thawed and cultured later. So finding ancient bacteria on Mars no longer seems far-fetched. — The Christian Science MonitorLetters to this column should be addressed to Letters C/o Edit Page Editor,

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