An icy planet with a 20,000-year orbit has been discovered passing through our solar system, leading to the re-emergence of theories about the existence of the mysterious Planet Nine
L91, as the icy rock is called, is one of a growing number of icy worlds with strange orbits discovered at the edge of the solar system.
According to scientists working on the Outer Solar System Origins Survey, L91 is an enigma defying previously established gravitational patterns, and its discovery has added to mounting evidence that there are gravitational disruptions going on beyond what we can see.
In the case of L91, some astronomers believe that the external disrupter could be a ninth giant planet, dubbed planet x, which is as yet undiscovered.
However, L91’s discovery team favors a scenario in which the disturbance is caused by something more mundane: a passing star, or the Milky Way’s gravity.
The Mail Online reports:
According to Science magazine, L91’s huge elliptical orbit means the icy world never comes closer than 50 times the distance between Earth and the sun (1 AU) and may swing as far out as 1,430 AUs.
Astronomers believe that the strange paths of distant object such as L91 and others, such as Sedna, are affected by the gravitational pull of a dense world far beyond the known eight planets: the as yet unidentified Planet Nine.
A team at the Outer Solar System Origins Survey (Ossos) have been tracking the icy worlds beyond Neptune to study their origin and why they take the paths they do.
Presenting their findings this week at a meeting of the American Astronomical Society’s Division for Planetary Science in Pasadena, California, members of the team indicate that L91 is being pulled by a distant object, resulting in its elongated orbit.