A huge planet that has never been seen by astronomers could be lurking, almost invisibly, at the dark edges of our solar system, some scientists believe.
By 1846, astronomers had pinpointed all the eight main planets – and have since found several other ‘dwarf planets’ including Pluto.
But the search goes on for the mysterious ‘ninth planet’ which is thought to sit far beyond Neptune in our solar system, said space expert Sara Webb.
There is a lot of evidence for the planet – thought to be up to 20 times further out from the Sun than Neptune – but it may be impossible to see with current technology.
The giant, hidden planet is thought to be 10 times larger than Earth and on an orbit that takes 10,000 or 20,000 years to go round the sun.
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