Life is elsewhere

Our reach must exceed our grasp or what8217;s a heaven for? NASA8217;s Phoenix lander has bits of Martian matter solidly in its clutch 8212; and it has the world agog, waiting to know what it could imply, and whether centuries of speculation have any support. Ten years ago, NASA even began a programme in astrobiology: a mix of astronomy, geology and biology that is dedicated to the study of extra-terrestrial life 8212; and an indication that it is not just cranks and dreamers, but also serious scientists who dedicate their careers to sketching such possibilities. There have been several mishaps on the previous 11 attempts, but Phoenix, which was assembled from the remains of a previous polar expedition, has proved to be a hardy little thing. It will scoop up and analyse samples of matter to ask the big question: could Mars support life?

Geological evidence and observation by other orbiters suggest that there might be vast amounts of ice hidden under the surface, which holds out possibilities of microbial life. But the crucial question is whether the ice melts, because 8220;liquid water8221; is essential for incubating life. If there was a significant wet patch on Mars, that would lend credence to the idea that low-level life could exist on the planet next door. Or the wilder, grander hypothesis 8212; that there might even have been more complex forms of life on Mars for a few million years, that died out, and meteors battered the planet for about 500 million years thereafter. Or perhaps, that microbial life originated in Mars and bits of rock, blasted by meteors actually made it to earth. Theories abound. Our appetite for them is the reason we are willing to foot the major costs of space exploration.

What explains our imaginative investment in Martiana, in little green men in their magnificent flying machines or in visions of colonising the red planet? The idea of a parallel world that we can make in our own image, or the idea that something alien could unwittingly reveal truths about our own situation? Whatever the reasons, neighbourhood visits rarely generate such excitement.