A wandering planet (also known as an interstellar planet, rogue planet, or orphan planet) is a planet that has been flung from its system and is no longer gravitationally bound to any star or other such object, and therefore orbits the galaxy directly. It has been estimated that there are twice as many wandering planets as there are stars. Isolated planets which were not ejected, but have always been free-floating, were formed in a similar way to stars.