Nomad planets are a type of extrasolar planet that does not orbit a star. They are believed to be formed in the same way as regular planets, but they are not bound to a star and instead roam freely through space. These wandering worlds are thought to make up a significant portion of the known universe’s planetary population.
The first nomad planet was discovered in 2013 by a team of astronomers led by Alexander Wolszczan of Pennsylvania State University. This world, dubbed PSO J318.5-22, is just six times the mass of Jupiter and orbits no star at all. It is thought to have been ejected from its home system after getting too close to one or more giant planets.
Since then, several other candidates for nomad planets have been found, but none have yet been confirmed beyond doubt. One such world is CFBDSIR 2149-0403 b, which was discovered in 2012 using the Canada-France Brown Dwarf Survey instrument on ESO’s 3.6 meter telescope at La Silla Observatory in Chile. This object is estimated to be between 13 and 20 times the mass of Jupiter and also appears to be unbound to any star. However, further observations are needed to confirm its status as a true nomad planet.
It is estimated that there may be billions upon billions of these objects roaming through our Milky Way galaxy alone. In fact, it has been suggested that free-floating worlds could outnumber stars by more than three to one! Given their vast numbers and strange lifestyles, understanding nomad planets could hold key clues about how our own solar system came to be—and how common Earth-like worlds might really be out there in the cosmos waiting to be found…