Discovered in 1930 at the Lowell Observatory, Pluto was demoted as a planet in 2006. Some want President Trump to take action ...

Debate has raged for two decades over whether Pluto should be considered a planet. Some want President Trump to take action via executive order.

In the cold, distant reaches of the Solar System, far beyond Pluto, astronomers have just identified what could be a new dwarf planet. It's called 2017 OF 201, a rock that appears to be some 700 ...

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, ...

Neptune’s largest moon, Triton, and the dwarf planet Pluto may have shared a common origin before being separated in the early solar system, an analysis of their composition suggests. Triton and Pluto ...

Beyond the asteroid belt lies a vast region dominated by giant planets and frozen worlds. This video explores the colossal ...

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, ...