But could there be a planet lurking in the depths of our solar system? It's possible that there is a planet in the outer solar system, but it is so far away and so cold that it would be difficult to see. In recent years there has been some evidence to support the existence of a super-Earth planet in the outer solar system. No if there's no planet 9, is that it for solar system bodies? While the latest survey of TNOs rules out a super-Earth, it leaves open the possibility of a smaller planet, sometimes called Planet 10.

Source: Forbes June 22, 2017 15:11 UTC