As the world mourns the loss of David Bowie, I am going to take the liberty of once again attempting to answer the age-old adage which has long kept us hooked to the silver screen: “is there life on Mars”?
Ever since Schiaparelli in 1887 first saw what he thought to be canals, supposedly the work of an advanced civilization, etched on the surface of Mars people have been eagerly speculating as to whether or not there really is life on Mars. This question has ever since been a staple subject for popular culture with a myriad of works from H. G. Wells’ The War of the Worlds to David Bowie’s “Life on Mars?” tackling the subject. I shall, however, attempt to approach it from a more scientific perspective.
After photographs of Mars were first returned to earth by NASA’s Mariner 4 it became clear that there were no advanced life forms living on the desolate surface and that Schiaperelli’s canals were, in fact, optical illusions. This is not wholly surprising when one considers the outcome of further observations which suggest that the surface of Mars is approximately -100˚C during the daytime and that it has virtually no atmosphere; conditions which seem antithetic to our usual ideas of habitual environments. This seems to leave those hoping for Martian life somewhat disappointed, however all hope is not lost.
Whilst the chance of finding higher life forms on Mars is now remote, there is still a chance that Mars might be harbouring simpler forms of life. There is, as yet, no evidence to prove this but there are some very slight hints that this maybe the case. One of these is the detection of methane in the atmosphere, first by telescopes, then by a European Space Agency orbiter. As methane reacts relatively quickly in the Martian atmosphere, the methane detected must have been produced relatively recently with two likely sources. The first is that the gas is being produced by volcanic activity on the planet, however no other indications of volcanic activity have yet been found. This leaves us to consider the second possibility that the methane is being produced by simple microorganisms on the surface.
A second piece of evidence pointing to the existence of life on Mars is the recent discovery by NASA that there may be liquid water on the surface. It has long been known that there were large quantities of ice present on Mars however the freezing conditions led most to believe that there was no possibility of liquid water and therefore life as we know it on the surface. However, data from a NASA satellite suggests that dark streaks visible on the surface may be due to the presence of small amounts of liquid water on the surface due to the presence of salts which lower its melting point. If this were true, it raises the possibility that life could exist due to these flows of liquid water.
Whilst this is at best proof of the existence of some of the simplest life possible, it would still be an incredibly significant discovery. This would show that life can exist elsewhere from Earth making the idea of life being a common occurrence in the universe all the more likely. However, as yet, it still remains to be seen to see if there really is life on Mars.
Original Image by Elizabeth Timoshchenko.