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Is life on Earth special? (Image: DuncanImages/Alamay)

Although intelligent life may exist on other planets, The Copernicus Complex by Caleb Scharf argues that Earth will still be special after all

IN THE 16th century, the Polish canon-cum- mathematician Nicolaus Copernicus suggested that Earth was not the unmoving centre of the universe; he claimed instead that .

The idea that Earth is nowhere special has been reinforced by subsequent discoveries. Our solar system is far from the centre of our galaxy, and that galaxy is just one of an almost uncountable number of others.

For most of us, this idea is humbling. For astronomers and cosmologists, it is useful, allowing them to make general statements about the universe based on observations made from Earth. However, Earth is the only planet known to support life – intelligent life at that – and astrobiologist thinks we should prepare for the possibility that we are special in some way, after all.

Special – but not unique. In 2000, argued in Rare Earth that intelligent life on Earth relied on so many unlikely accidents that we are probably alone in the universe. This is a step too far for Scharf, and rather like saying that a spectator at a baseball game lucky enough to catch a ball must therefore be alone in the stadium.

In a big enough universe, extraordinary things happen all the time. Our solar system is a case in point: , with rocky planets closer to the sun and gas giants farther out.

The Copernicus Complex is an astrobiology book framed within a philosophical question. It does not discuss why life (intelligent or not) exists. It is, nonetheless, an easy-to-read summary of astrobiology research, which is no mean feat considering the weighty topics it deals with.

This article appeared in print under the headline “An ordinary miracle”