Astronomers have discovered a mystery object in the depths of the solar system which orbits the sun backwards at an unusual tilt.
The icy world is believed to be less than 200km in diameter and has been classified by scientists as a trans-Neptunian object (TNO).
Scientists are most interested in why the TNO orbits the sun in a plane which is tilted 110 degrees to plane of the solar system, New Scientist reported.
Normally, planets orbit on a flat plane, which forms in a disk of dust that is generated just before a star’s birth.
But the researchers who made the discovery at the Harvard-Smithsonian Center for Astrophysics believe the TNO must have been knocked out of a more conventional orbit by something else.
Harvard’s Matthew Holman told New Scientist: “It suggests that there’s more going on in the outer solar system than we’re fully aware of.”
Earlier this year, scientists speculated that a huge world ten times the size of Earth, known as Planet Nine, is lurking even deeper in the solar system.
Holman’s team believe the TNO is orbiting the sun as part of another group of objects in a “highly inclined plane”, but through testing dismissed the idea that the objects could be linked to Planet Nine’s gravitational pull.
Holman said that not even an undiscovered dwarf planet could explain its unusual orbit.
California Institute of Technology’s Konstantin Batygin, who discovered the possibility of Planet Nine’s existence earlier this year, told the New Scientists he was excited about the TNO’s discovery:
“Whenever you have some feature that you can’t explain in the outer solar system, it’s immensely exciting because it’s in some sense foreshadowing a new development.”
Scientists nicknamed the TNO “Niku”, the Chinese adjective for rebellious.
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