In this edition of Space, Euronews correspondent Jeremy Wilks reports from the Observatory of Geneva - home to experts in exoplanets, the name given to planets outside our solar system.
So far they have managed to find more than 3500 exoplanets but they believe there could be literally billions of them across the Milky Way.
The first exoplanet to be discovered was what's known as a hot Jupiter, a giant gas planet orbiting close to its star. That discovery, made by University of Geneva professor Michel Mayor in 1995, kick-started a revolution in astronomy, one which at the time of our interview put the number of exoplanets at 3559 and counting.