Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously ...

Astronomers used a telescope in Hawaii to find a new object on the outer edges of our solar system, helping to fuel evidence of a long-standing theory about Planet Nine, or Planet X. For years, ...

Our fundamental understanding of Neptune and Uranus may be completely wrong, say researchers rethinking our solar system.

New models suggest Uranus and Neptune may hold far more rock than expected, raising questions about how these distant planets formed.

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

Neptune’s supersonic winds and icy storms revealed a planet so extreme that it forever changed our picture of the solar ...

There may be more ringed objects in the outer solar system than anyone knew. This week, researchers revealed that the egg-shaped dwarf planet Haumea — one of four known diminutive planets that circle ...

The Hubble Space Telescope has peered at Uranus, left, and Neptune to study the so-called "ice giant" planets, but little is known about their interior composition. Credit: NASA / ESA / M. Showalter / ...

A team of astronomers has announced the discovery of some of the smallest planets yet detected beyond our solar system. The two newly discovered planets represent a new class of extrasolar planets, ...