The newly identified cluster of Kuiper Belt objects lies about 4 billion miles from the Sun, offering fresh clues about how ...

Sedna is drifting into a part of its path where human technology can finally contemplate catching up, and that window will ...

With sapphire waterfalls, lava rain and orbits around dead stars, these distant worlds push the limits of what’s possible.

For the first time since Pluto was demoted, the idea of a true ninth planet is edging from speculation toward something ...