Two decades ago , the planets of our Solar System were the only single we knew to be orbiting a Sun - comparable star . Of course , we had theorized there would be many others around other stars – but none had been found .
So October 6 this workweek marked a momentous occasion , as NASA heralded the20th anniversaryof the first satellite to be find orb a Sun - similar principal , 51 Pegasi b. This was arguably not the first exoplanet find ; that honor belongs to PST B1257 + 12 A , a planet revolve apulsarthat was light upon almost by chance event three class before , although there is somecause for disceptation . But 51 Pegasi Bel was the first spotted around a “ normal ” champion like our Sun .
Its discovery , by uranologist Michel Mayer and Didier Queloz , was herald inNatureon October 6 , 1995 . They happen it using the radiate velocity method , which detects the gravitative influence of a planet on its star . 51 Pegasi b is half the mass of Jupiter but orbits closer to its star than Mercury does to our Sun , a image for so - calledhot Jupiters .
Since then , major planet hunting has move from a bang science to one of the major bailiwick in uranology . Thousands of exoplanets have now been found , most using NASA ’s tremendously successful Kepler space telescope . coming infinite observatories , include theJames Webb Space Telescope(JWST ) and theTransiting Exoplanet Survey Satellite(TESS ) , will carry on to study and hunt for these foreign new worlds .
The “ holy grail ” for planet Hunter is to detect another major planet on the dot like Earth . That is , one with the same age , size of it , and mint , orbiting a star like our Sun at exactly the same space . The tight we ’ve come so far isKepler 452b(second from right in the image above ) earlier this year , but at 1.6 time the size of it of Earth , it does n’t quite go the bill .
We can look back 20 age , though , and see just how far we ’ve descend . Along the mode , we ’ve discovered planets we never think possible : hot Jupiters in tight orbits , jolty worldsmade of diamondand even superintendent - ground , sublunary planet much larger than our own . Who knows what else is out there , waiting for us to find .
