As long as people have looked up at the night sky, they have wondered whether humanity is alone in the universe. Of places close enough for people to visit, Mars is the only one that anybody seriously thinks might support life. The recent confirmation of a five-year-old finding that there is methane in the Martian atmosphere has therefore excited the hopes of exobiologists—particularly as the sources of three large plumes of the gas now seem to have been located. These sources are probably geological but they might, just, prove to be biological.

The possibility of life on Mars is too thrilling for mankind to ignore. But how should we explore such questions—with men, or machines? Since America is the biggest spender in space, its approach will heavily influence the world’s. George Bush’s administration strongly supported manned exploration, but the new administration is likely to have different priorities—and so it should.

Bug-eyed monsters

Michael Griffin, the boss of American’s National Aeronautics and Space Administration (NASA), a physicist and aerospace engineer who supported Mr Bush’s plan to return to the moon and then push on to Mars, has gone. Mr Obama’s transition team had already been asking difficult questions of NASA, in particular about the cost of scrapping parts of the successor to the ageing and obsolete space shuttles that now form America’s manned space programme. That successor system is also designed to return humans to the moon by 2020, as a stepping stone to visiting Mars. Meanwhile, Mr Obama’s administration is wondering about spending more money on lots of new satellites designed to look down at the Earth, rather than outward into space.

... contd.