When I was a boy it seemed certain that somewhere ‘out there’ were other worlds like Earth – strange and wonderful plants, birds and animals and civilisations, good and bad like our own. People wrote stories, mathematicians calculated the chances. The universe was vast and becoming vaster. At home our old encyclopaedia knew nothing of other galaxies beyond our own Milky Way, yet ‘out there’ is now known to be filled with others. Science fiction writers had to invent hyperspace travel and warp speed, stargates and wormholes in space to cover the limitations of distance and speed of light.

And yet…

Even as the twenty-first century approached, when Dan Dare and Jeff Hawke had grown into Captain Kirk, Luke Skywalker and E.T. there were hairline cracks. I remember an article listing the factors which led to the development of life here, concluding that there would probably be at least a hundred thousand intelligent civilisations like our own. I noticed that among the factors the writer had not included was the influence of the Moon. We are almost a twin planet with a satellite so large it produces powerful tides that have driven adaptation and evolution in the tidal zone so critical as life moved from sea to land.

I wondered how many planets in the life zone of other stars had a similar large companion; one in fifty or less did not seem unreasonable, That would reduce the number of other civilisations to two thousand. Three more such missed factors would mean we were probably alone. A bleak prospect.

Since then work by scientists such as Nick Lane, evolutionary biochemist of University College London, on the origins of nucleated, cellular life which found that the common basic structure of mitochondrial DNA points to a single, one-off event in the origin of all cellular life: plants, insects, us, everything in the four and a half billion years this planet has existed (Google Nick Lane ‘The Vital Question’). Derek Bickerton, Professor Emeritus of Linguistics, University of Hawaii has found strong evidence of a similar one-off development in language and spare brain capacity. In ‘More than Nature Needs’ he investigates why, in the billions of years since complex creatures evolved on Earth, we are the only species that can study the universe in which we have evolved.

It is noticeable that more recent science fiction, such as Gravity and The Martian, is of human endeavour fighting the perils ‘out there’.
Are we alone? If so is that a bleak prospect?