Some scientists hypothesize that a mysterious, gigantic 9th planet may be lurking at our solar system’s edge. Why haven't we ...

For the dwarf planet candidate, one trip around the sun takes over 24,000 years. Its orbit challenges a proposed path for a hypothetical Planet Nine.

Shares of Planet Labs ( PL 11.24%) climbed on Thursday, closing up 11.2% as of the 1 p.m. ET early market close for the ...

Scientists may have discovered a dwarf planet far beyond Neptune — an unearthing that may disprove a longstanding theory ...

Charles Leclerc let fly an untelevised, X-rated radio rant after qualifying in sixth for the British Grand Prix.

Computer simulations show that planets could be flung out of the inner solar system, supporting the possible existence of a ...

The planet, which astronomers believe is orbiting a young red dwarf star approximately 34 light years away, has been dubbed ...

New research shows there is at least a 40% chance of the existence of Planet Nine, but scientists are still looking for definitive proof.

A new dwarf planet, discovered beyond Neptune and described as Pluto's 'cousin,' could void the hypothesis of a Planet X in our solar system.

To get a glimpse of the “Swift Planet,” EarthSky suggests waiting for the sun to set before looking west for the planet ...

It is also sometimes called Planet X, a name proposed for a hypothetical world beyond Neptune more than a century ago. Back in 1930, ...

Planet X has been hypothesized for years, but how such a planet could have appeared in the outer Solar System has long stumped scientists. A new study in Nature Astronomy reveals a novel theory, ...