Our fascination with Mars has sent numerous missions, probes and rovers to the Red Planet in order to discover its secrets and answer whether or not it may one day be made habitable for humans. Indeed at the very moment NASA’s latest rover, Curiosity, is busy gathering various data on the Red Planet, collecting soil samples, atmospheric readings and the like in order to understand Mars’ past and to see whether or not life ever existed on the now desolate planet.
Of course it would make perfect sense for answers to Mars’ past to come from Curiosity and the numerous other probes and rovers sent to the planet but in recent research, scientists have turned to a more home grown solution for answers. Studying clay found in old atomic bomb test sites in the Pacific, researchers from the University of Poitiers in France have concluded that Mars may not have been as wet and warm as scientists have imagined. It is believed that around 3.75 billion years ago, Mars was apparently running with water.
The clay samples taken from rocks found at the Mururoa Atoll in French Polynesia is similar to clay found on the Martian surface and using this, the French researchers have extrapolated that Mars was most likely not ‘awash’ in water as previously thought. While the large deposits of clay spotted by satellites on the Martian surface are believed to have formed as a direct result for large amounts of water weathering rocks, the clay found on Mururoa formed quite differently. Instead of liquid water weathering rocks, the Mururoa clay was formed by precipitation from waiter-rich volcanic rock. This process did not require large amounts of water and the present study, published in the journal, Nature Geoscience supposes that the same is applicable to Mars.
Speaking about the research, lead researcher, Prof Alain Meunier said, "Mars was not as warm and wet in its earliest time as some have suggested. I do not believe in an early ocean on Mars. But [The Mururoa process] explains only the earliest generation of clays on Mars, in the early Noachian period. In later periods, liquid water has existed on Mars' surface; that is undoubtedly the case."
But some scientists have disagreed with the research, saying that while The Mururoa process may explain some clay formation, it cannot account for the vast amounts of clay found on Mars as Prof John Mustard of Brown University in the US says, “The question is: how do you generate thick sequences of this stuff? Their model cannot, I don't think, explain a Mawrth Vallis and other thick sections where we can quite clearly demonstrate many hundreds of metres, if not more, of clay formation. Mawrth Vallis has far too much clay to be produced by this process. The amount of clays produced by this degassing process is a relatively small amount.”
Prof Mustard instead supposes that the bulk of the clay was perhaps formed sub-surface and it will be interesting to see if Curiosity will be able to analyse some clay samples.