On Oct. 10, 1846, William Lassell peered through his 20-foot reflector in Liverpool, England. Lassell was a self-funded ...

CAPE CANAVERAL, Fla. - Chalk up one more moon for Neptune. NASA announced the discovery of Neptune's 14th moon Monday. The Hubble Space Telescope captured the moon as a white dot in photos of Neptune ...

Astronomers have discovered a distant dwarf planet orbiting beyond Neptune — a frozen world so far from the Sun that it challenges everything we know about how the solar system formed.

It’s often said—we said it again ourselves just last week, in fact—that our own Solar System isn’t as typical as scientists once imagined. We’ve got four small, close-in, rocky planets (Mercury ...

A new study suggests yet another theory for a possible extra planet in our solar system, likely of a size between Mercury and ...