As a tangent to yesterday’s post (and also because discussing bleak prospects for Mars appears popular), there’s another point in James Lovelock’s Gaia: A New Look At Life on Earth that seems relevant for today. It’s just been announced that NASA will send another rover to Mars in 2020 to compliment the work of the current Curiosity rover in its search for life. While Curiosity has been generally examining the environment with its hi-tech equipment to see if it could ever have been fit for life, this new rover would focus on studying the planet’s geology.
When writing the book, it was Lovelock’s view that the development of life on a planet inevitably acts to terraform that planet to make it even more fit to harbour life – such as how on Earth life has regulated our atmosphere in the last 3 billion years to keep the temperature constant, despite the fact it ought to be lowering. If Mars has ever had life on it, then this life should have modified the planet to make it more habitable, thereby leading to more life. This doesn’t necessarily mean that Mars should still be habitable now if it ever sustained life – some catastrophe could have destroyed the atmosphere, for example – but signs of former life ought to be more obvious. Certainly, it would suggest with certainty that no life exists now. In this theory I think it’s still possible that life never developed past basic bacteria before being wiped out, but the chances of such a short lifespan can be considered unlikely. If this is true then our search for life on Mars is probably in vain.
That’s not to say I don’t think we should be sending rovers to Mars. Quite the contrary! There is still so much we can learn from our neighbours whilst developing our own technological capabilities. I just don’t think we should be getting our hopes up for any big announcements.