7 September 2010
…Well that is the billion dollar question !
The planet Mars is place of mystery, it’s the most Earth like of the planets in our solar system gaining our affection and fascination for centuries, and we now have the place mapped down to a resolution of one metre. This freeze dried desert world continues to tease us with tantalising hints of comfortable conditions for life in the past, or even right now. Lakes and seas lapped Martian shorelines eons ago, evidence for huge floods that carved out landforms similar to Earth have been seen, and a very interesting fact is that Mars produces vast plumes of methane today that can only be a product of either geological, or biological activity.
Is Mars a home for life? The debate rages on, the evidence for and against Martian life past or present seems to swing back and forth like a pendulum. In recent years though it has been looking more favourable with new discoveries made by scientists using the flotilla of spacecraft and rovers on and around our sister planet.
This is the latest nugget in the Martian life or no life conundrum, although it is exciting scientists cannot say if life ever existed on Mars. Way back in 1976 Nasa scientists put down the two Nasa Viking landers on the red planet. The spacecraft analysed the Martin soil, and direct evidence for life was expected…but alas, no alien biology or carbon rich molecules were found.
The Nasa Viking 1 Spacecraft on Mars in 1976
But since those far back days we have been landing on Mars, studying the place from orbit, and driving across it…well our robots and spacecraft have. One of those was the Nasa Phoenix Mars Lander that dropped in for a visit in 2008. But experiments made by Phoenix at its landing site in the far north of Mars have caused scientists to look again at just what the Viking spacecraft found, or rather didn’t find.
In 1976 the landers heated the soil during their experiments, and no organic chemicals were found apart from some chlorine compounds, but these were discounted at the time as contamination from cleaning fluids. But 32 years later the Nasa Phoenix Mars Lander found something called perchlorate, an ion of chlorine and oxygen. Scientists doing experiments in the Atacama Desert in Chile have now realised that perchlorate destroys organic compounds in the soil when heated, and also gives off chlorine compounds. Those exact same chlorine compounds that were found by Viking in 76 and discounted.
So what was thought to be contamination maybe was not, and the experiments the Vikings did could have been effectively destroying the very things they were looking for. So organics could be present in the Martian soil after all, but even this doesn’t actaully prove anything about life. Organics can be produced from both biological or non biological sources.
The Mars methane plumes, it’s ancient warmer wetter past, the ancient “Martian fossil” ALH84001 that caused a worldwide media frenzy in the 90′s. The red world is elusive and won’t quite give up its secrets, the real truth about this amazing place is always just out of reach. But we’re getting there, Nasa will land the Curiosity Rover on Mars in 2012 that will be able to check for organics in the soil and rocks…and importantly it will be able to travel across the surface.
DISCUSS this, or go to the HOME PAGE
