- The Guardian,
- Thursday March 16 2000
Evidence for life on Mars might be in the soil - and overlooked because all previous missions had the wrong detector system.
Organic chemicals such as alcohol, vinegar or oxalic acid - the stuff that makes rhubarb leaves taste bitter - might have existed on Mars, but landing craft would have failed to detect their byproducts, according to a team of US scientists.
The harsh, thin Martian atmosphere would have altered such life-associated chemicals in various ways, Steve Benner of the university of Florida in Gainesville tells the New Scientist today.
The Florida team simply looked at the oldest evidence from Mars and saw a missed opportunity. In the fierce ultraviolet radiation of the Red Planet, organic carbon-based molecules would have been dismantled, or transmuted into something else. The most stable byproduct of acetic acid or oxalic acid or ethanol would be a carboxylic acid. In 1976 the Viking robot landers revealed a cold, arid desert after they scooped up Martian soil and heated it to 500C for 30 seconds and analysed the vapour. But, the scientists point out, carboxylic acid takes longer than 30 seconds to turn to vapour.
The argument will kick new life into the faltering life-on-Mars debate. Two weeks ago the journal Nature carried a blow for the faithful: the sulphur in the Martian soil could be explained without help from biological processes, a study said.
If there are traces of carbon-based life on Mars, says Colin Pillinger of the Open university, they will be detected by the British lander Beagle2, to be delivered by a European mission in 2003.
