Professor Didier Queloz hunts for extreme worlds and Earth twins in Cambridge’s Battcock Centre for Experimental Astrophysics. Here he tells of the moment in 1995 when he became the first to discover a planet that orbits a star other than our Sun.
Astronomers had speculated as to the existence of these distant worlds – called exoplanets – but, until the discovery of 51 Pegasi b by Queloz and Professor Michel Mayor at the University of Geneva, no planet other than those in our own solar system had ever been found.
Of the 1,900 or so confirmed exoplanets that have now been found, many are different to anything we ever imagined, challenging existing theories of planet formation.
For instance, 51 Peg resembles the gas giant Jupiter. But unlike our distant cousin, which is located in the further reaches of our solar system and takes 10 years to orbit the sun, 51 Peg ‘hugs’ its sun, orbiting every four days. It’s been hailed as an example of a whole new class of ‘roaster planets’ or ‘Hot Jupiters’ and has prompted scientists to wonder if large planets are able to migrate closer to their suns over millions of years.