Mars

Mars doesn’t shine as brightly in the brief summer nights as it did earlier in the year. But it’s still the most tangible, almost touchable world out there. No planet except our own has been more studied, more watched, more visited than Mars. And unless you are very young or very optimistic it is the only planet out there that in our lifetimes we may see visited by our species. We know an extraordinary amount, but there remain great mysteries. What are the enormous caves recently discovered in the Northern mountains, and what’s in them? Was there life on Mars when it was warmer and wetter? Is there life there still?

Intriguingly in 2004 traces of the gas methane were detected in Mars’ atmosphere. Methane is quite unstable and would naturally break down, meaning if it’s there it must be replenished. But by what? There are a few potential sources, but they don’t fully explain it . There is no volcanism on Mars so geological causes are very unlikely. Meteorites and asteroids can carry methane, but the amounts that could be delivered are tiny in comparison to the amounts found. One explanation is that the methane could have a biological origin. On Earth methane is found deep under the ground a product of the breakdown of plants and animals. We use it and call it natural gas. If Mars had life in the past it is possible that the decayed remains of it lie deep under the Martian surface. It is not inconceivable that they have decomposed in the same way. Of course it would require bacteria or something similar to have caused the decomposition. A beguiling possibility emerged last year when NASA announced that seasonal plumes of methane had been discovered coming from the Northern surface of Mars. The area in fact where the caves are located. Could it be that bacteria survive deep underground in those caves, springing into life during the Martian summer?  Perhaps one day an astronaut will descend into one of those deep caves and find out.