To the naked eye Mars is unmistakeably red, the colour of blood and, by association, of war, and its light fluctuates in intensity as it wanders one way and then back again across the sky. It has been an object of fascination and speculation for all recorded history. Looking through a telescope more than a hundred years ago, Percival Lowell thought he spotted canals on Mars and hypothesised the existence of intelligent life, desperately building canals to fight off the encroaching desert. (The canals were in the first instance a mistranslation of the canali - channels - detected by the Italian astronomer Giovanni Schiaparelli.) Lowell was wrong, and although Mars is covered in spectacular geological features, his canals aren't one of them. We know, because we've looked. At the time of writing there are three spacecraft orbiting Mars and three more trundling about its surface. The latest is a Nasa lander called Phoenix, resident on Mars since 25 May, which is currently chugging around the north polar region looking for water and evidence of habitability.

LRB 11 September 2008 | PDF Download