Heads up, stargazers, as the dog days of summer take hold this week, a series of planets enter their retrograde phase, leaving plenty of room for reflection as the energy signature and patterns slow ...

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

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 ...

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, ...

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

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

The five dwarf planets recognized by the International Astronomical Union are Pluto, Ceres, Eris, Haumea and Makemake—and these are pictured with 2017 OF201 in a telescope image. Dwarf planets: NASA / ...