Astronomers believe they have uncovered evidence of a previously unknown ninth planet lurking in the not-too-distant reaches of the solar system. This hypothetical world, dubbed "Planet Y," could be ...

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 ...

Earth has a newly-discovered neighbor in the solar system. But the heavenly body – possibly a dwarf planet à la Pluto – isn't a frequent visitor. Located beyond Neptune, its extreme orbit ...

It's an evocative idea that has long bedeviled scientists: a huge and mysterious planet is lurking in the darkness at the edge of our solar system, evading all our efforts to spot it. Some astronomers ...