Nomad Planet

There are millions of wandering, homeless planets in the Milky Way. Such a planet which has been ejected from its system and is no longer gravitationally bound to any star, brown dwarf or other such object, and that therefore orbits the galaxy directly is called a nomad planet or rogue planet.  The researchers say that these intriguing cosmic bodies would belong to a whole new class of alien worlds, shaking up existing theories of planet formation, and may also raise new and tantalizing questions in the search for life beyond Earth. The PTI news says that over the past several decades, astronomers have keenly hunted for planets outside our solar system. So far, the search has turned up more than 700 of these exoplanets. Almost all of these newfound worlds orbit stars, but last year, scientists found about a dozen planets with no discernible host star.  One doubtful such nomad planet is Cha 110913-773444.