A surprising number of scientists believe in little green men

In 1928, a young physicist and engineer named Karl Jansky began working at Bell Telephone Laboratories, tasked with investigating any sources of static that could interfere with long-distance radio communication. Cobbling together a system of antennae on a merry-go-round, he successfully found that thunderstorms were annoying in just this way. But there was a small bit of noise left over, and he kept scanning the sky to locate the culprit. To his surprise, he eventually found it was coming from Sagittarius in the centre of the Milky Way. He christened it ‘star-noise’. We now know that he had correctly identified the emanations from a supermassive black hole; and, quite by accident, he had invented the new science of radio astronomy.

Chris Lintott’s book, an amiable advert for serendipitous wonders, is concerned in part to overturn a certain naive view of science: that it consists of forming hypotheses and then testing them. Quite as often, the author – an Oxford astrophysicist and presenter of The Sky at Night – points out, it consists of the opposite: observing unexpected things and then scrabbling around for possible explanations.

In astronomy, indeed, this seems to be the rule rather than the exception. When the Hubble space telescope was first pointed at a tiny patch of seemingly empty space and left to expose its sensors for 100 hours, not much was expected of the exercise. But the resulting picture – the first Hubble ‘deep field’ image – was almost sickening in its unfathomable majesty, a teeming riot of extremely distant (and therefore very young when their light was emitted) galaxies of hitherto unexpected shapes: ‘twisted discs, bizarre, sharp-angled systems’, and one ‘like a strange species of porcupine’. Taking a punt on a long exposure in this way, Lintott relates, ‘changed the way that astronomy was done’ from then on.