Planet X
Is Planet Nine tilting our Solar System?
The existence of a ninth planet in our Solar System could provide the solution to an age-old problem concerning the orbits of the planets.
Is there no Planet Nine after all?
A 9th planet could be shepherding objects in the outer Solar System into strange orbits, or it could be the gravity of objects beyond Neptune.
Four objects examined in Planet 9 search
Four unknown bodies are being examined in the hope of finding the hypothetical ninth planet of our Solar System beyond the orbit of Neptune.
Join the hunt for Planet 9
NASA is looking for help analysing data in the hope of discovering the ninth member of our Solar System.
Have astronomers discovered a ninth planet?
Since the declassification of Pluto in 2006, our Solar System has been considered an eight-planet system. But a new discovery by astronomers may have revealed a new contender for the ninth member.