Researchers at the California Institute of Technology have found evidence in the outer solar system of an object that could be a real ninth planet.
They have given it the nickname ‘Planet Nine’ or ‘Planet X’.
It has a mass about 10 times that of Earth and orbits about 20 times farther from the sun than Neptune. That means it would take this new planet between 10,000 and 20,000 years to make just one full orbit around the sun!!
However, researchers haven’t actually seen the planet, but they have found evidence of a gravitational pull suggesting a planet is there.
Since 2006 when Pluto was downgraded to a dwarf planet, scientists have thought we only had 8 planets in a our solar system. Now we may be up to nine again.
Check out a video here about the new planet