Who really discovered the first exoplanet?
While speculation about planets beyond the Solar System dates back over 2,000 years, actually finding them proved hard – and controversial.
During the 1960s, credit for finding the first exoplanet went to Dutch astronomer Peter van de Kamp, who claimed to have found two planets orbiting a nearby red dwarf called Barnard’s Star. Based on analysis of tiny wobbles in the star’s location over 30 years, the claim stood until the mid-1970s, when it emerged the cause was a wobbly telescope lens, not the effect of invisible planets on the star.
In 1991, two British astronomers claimed to have found a planet orbiting a pulsar, a remnant of a dead star. Within months, this too had been shown to be an illusion. By then, the Polish astronomer Aleksander Wolszczan and colleague Dale Frail had announced the discovery of at least two planets around another pulsar by detecting subtle shifts in its emission of radiation.
While subsequently confirmed, these planets and their parent ‘star’ have little in common with our Solar System. Credit for the discovery of the first planet orbiting a normal star thus goes to Swiss astronomers Michel Mayor and Didier Queloz, who found a Jupiter-sized object orbiting the star 51 Pegasi in 1995.
Robert is a science writer and visiting professor of science at Aston University.