Mike Brown is convinced that beyond Neptune, at the far reaches of our solar system, there's an unseen giant planet. "This is the 5th largest planet in our solar system, lurking out there ...

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 ...

It's a question that has baffled scientists around the world for years. Is there really a ninth planet hiding in our solar system? And if so, how do we find it? Now, researchers from Rice ...

Astronomers announced Thursday that they had detected the most promising "hints" of potential life on a planet beyond our solar system, though other scientists expressed skepticism. There has been ...

They theorized that a potential planet’s long orbit would enable them to see it move across the sky. They found 13 pairs of dots that could be explained by a moving planet that resembled Planet ...

The planet "splashed down" into the star, sending a giant plume of gas into space that gave the star a ring. The James Webb Space Telescope (JWST) has been studying the scene of a dramatic ...