For a few years now, astronomers have been detecting hints that there may be a mysterious planet lurking undetected in some of the farthest reaches of our solar system.
But a new study suggests there may be a great deal more going on in the cold, dark regions of space beyond the eighth planet orbiting our sun, Neptune.
Scientists have discovered a bizarre new object, less than 124 miles (200km) across, with a strange tilted orbit that sends it high above the flat orbital disk of the rest of the solar system.
They found the new minor planet, which they have named Niku after the Chinese for rebellious, which seems to be part of a cluster of other similar objects and icy planetoids with similar orbits.
It suggests they may have been pushed or pulled into this strange orbit by something far larger orbiting beyond Neptune.
At first the astronomers thought it could be the hypothetical Planet Nine that astronomers have been hunting for far beyond Pluto on the farthest edge of the solar system.
However, they found Niku and its fellow tiny worlds are too close to the rest of the solar system to have been tugged out of place by this theoretical planet.
Instead, they suggest Niku and its neighbours may have been swept into their strange orbit by another undiscovered dwarf planet like Pluto or Ceres.
But they were unable to find any evidence for this either, which has left astronomers baffled and excited at the prospect of something waiting to be discovered in this region of the solar system.
Dr Matthew Holman, an astronomer at the Harvard-Smithsonian Centre for Astrophysics who was part of the team that discovered Niku, told New Scientist: 'It suggests that there's more going on in the outer solar system than we're fully aware of.'
Niku is around 160,000 times fainter than Neptune and the astronomers esimtate it is around 11 times smaller than the dwarf planet Pluto.
Niku was found to orbit 110 degrees off the orbital plane of the solar systemOrbiting at around 3.25 billion miles from the sun, it falls into a class of minor worlds known as trans-Neptunian objects, which sit beyond the giant planet Neptune.
These icy worlds are not comets but instead considered to be minor planets.
Another class of minor planets with unstable orbits known as centaurs also orbit between Jupiter and Neptune.
These often have unusual orbits as the gravitational pull of the gas giants tugs them out of synchronisation with the rest of the solar system.
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