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 ...

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.

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

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

Despite this, "people have considered a whole host of different orbits for these hypothetical planets," Chad Trujillo, an astronomer at Northern Arizona University, said to Science News. "This object ...

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

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.

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, ...

The scientists announced in a news release that they have found a trans-Neptune Object(TNO), code-named 2017OF201, located past the icy and desolate region of the Kuplier Belt.