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 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.
The so-called “planetary-mass object” described by the scientists from LPL appears to affect the orbits of a population of icy space rocks in the Kuiper Belt. Distant Kuiper Belt objects (KBOs) have tilted orbits around the sun. The tilted orbital planes of most KBOs average out to something called the invariable plane of the solar system.
But the orbits of the most distant KBOs tilt away from the invariable plane by an average of 8 degrees, which signals the presence of a more massive object that warps its surroundings with its gravitational field, researchers said in a study due to be published in The Astronomical Journal.
“The most likely explanation for our results is that there…