Far beyond Neptune, something heavy appears to be tugging on the outer solar system, bending the paths of distant icy worlds ...

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, waiting to ...

Astronomers have used NASA's James Webb Space Telescope to find strong evidence for a planet orbiting a star in the triple system closest to our own sun. At just 4 light-years away from Earth, the ...

This artistic photo compilation compares the size of Planet Nine (right) to Earth (left). Dr. Konstantin Batygin, professor of Planetary Science at Caltech, made a joke that turned out to be true. In ...

A powerful new observatory is the best hope yet for finding the elusive Planet 9, a large planet that some scientists say is hidden in our solar... If Planet Nine is out there, this telescope might ...