Rock abrasions from NASA's Opportunity rover (left) and Curiosity rover (right), the latter of which produced grey tailings suggesting the presence of partially oxidised chemicals compatible with habitability. Images via NASA/JPL-Caltech/Cornell/MSSS
NASA’s Curiosity rover, which has been exploring the Gale Crater on Mars since August last year, has discovered conditions once suited to supporting life on this neighbouring planet.
The robotic rover collected a sample of sedimentary rock near an ancient stream bed in the crater last month. Scientists analysed this and have identified sulphur, nitrogen, hydrogen, oxygen, phosphorous and carbon –some of the key chemical ingredients of life.
Does this mean that there was once life on Mars? “A fundamental question for this mission is whether Mars could have supported a habitable environment,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Programme at. “From what we know now, the answer is yes.”
Data from Curiosity’s sample analysis and chemistry and mineralogy instruments indicates that the Yellowknife Bay area that it is now exploring was once a habitable environment for living microbes. It is interpreted that this area was once the end of a river system or an intermittently wet lake bed that could have provided chemical energy and other favourable conditions for life.
Scientists have also discovered clay minerals and a mixture of oxidised, less-oxidised and non-oxidised chemicals in Curiosity’s samples. “The range of chemical ingredients we have identified in the sample is impressive, and it suggests pairings such as sulfates and sulfides that indicate a possible chemical energy source for micro-organisms,” explained Paul Mahaffy, one of NASA’s principal investigators of Mars sample analysis.
The partial oxidisation of chemicals in the samples has given rise to the idea of an earlier ‘grey Mars’, before it was the Red Planet, when conditions would have supported life. An additional sample will be used to help confirm these results.
