Planet 10? Another Earth-Size World May Lurk in the Outer Solar System
A planet-size object may be orbiting the sun in the icy reaches of the solar system beyond Pluto.
Scientists at the University of Arizona’s Lunar and Planetary Laboratory (LPL) have determined that an unseen object with a mass somewhere between that of Earth and Mars could be lurking in the Kuiper Belt, a region beyond Neptune filled with thousands of icy asteroids, comets and dwarf planets.
In In January 2016, a separate group of scientists predicted the existence of a Neptune-size planet orbiting the sun far, far beyond Pluto — about 25 times farther from the sun than Pluto is. This hypothetical planet was dubbed “Planet Nine,” so if both predictions are correct, one of these putative objects could be the solar system’s 10th planet.