Friday, 16 March 2012

The Prehistory Of The Red Planet Part Two

A couple of months ago, I reported on geological developments into the prehistory of the red planet. Analysis of soil brought back by the Phoenix probes in 2008 showed that liquid water only existed on the surface of Mars for less than 10,000 years, showing that there was not enough time for life to form above the ground. While micro-organisms may still be living in subterranean caves or buried in the soil and ice at the poles, they certainly never colonised or lived permanently on the surface.

New discoveries are once again defining how Mars has developed as a planet and how these developments may have affected the origins and evolution of its potential inhabitants. B.C shall, once again, travel through the space to our neighbouring planet where analysis of its geology, reveals some surprising facts about where Martian life could have arisen from inert chemicals.

For abiogenesis to occur, the right conditions and elements have to be present. There has to be an abundant energy source, which can be anything from volcanic heat, lightning to the powerful radiation emitted by the sun; and there has to be a high concentration of hydrogen, oxygen, nitrogen and phosphorus.

Many creation myths detail the first humans as constructed from clay. Yet this story is more accurate than one might think because these elements are often locked up in minerals which are particularly abundant in mud and clay. This will be affected by a planet's geology. In light of this, a team of scientists from Brown University used satellite images taken by the Mars Odyssey Spacecraft to find lakes, where water once rushed in as well as out.

The satellite images of the lakes
The team analysed light reflected off the ancient lake beds to determine the chemical and lithological composition. They were looking for evidence of mud and clay. Out of the 226 lake beds surveyed, they found that only 79 contained the correct minerals. This is in keeping with previous Martian studies which showed that liquid water existed on the surface of the planet for a few thousand years only. Significantly longer periods of time are needed to produce large clay deposits.

Yet it does not necessarily rule out the possibility that life did once exist on Mars. The lakes, found in the Nili Fossae region had very thick layers of sediment. Erosion revealed crusts as old as 4.1 billion years, showing that clay depositions, while not on a global scale, were present and had occured in the same area for a long period of time. The placement of these clay lakes narrows down the places where we might find Martian fossils or even life itself. Until humans reach the Red Planet, the theory remains just that, a theory. So for the moment we can only echo David Bowie's words: 'is there life on Mars?'