Over the past century, astronomers have speculated about the existence of a mysterious 9th planet lurking in the outer ...

There could be a ninth planet in our Solar System after all - and no, it's not Pluto. Instead, it's the theoretical Planet X, also called Planet Nine, a wide-orbit planet that would circle the Sun ...

Alfredo has a PhD in Astrophysics and a Master's in Quantum Fields and Fundamental Forces from Imperial College London.View full profile Alfredo has a PhD in Astrophysics and a Master's in Quantum ...