Earth has a newly-discovered neighbor in the solar system. But the heavenly body – possibly a dwarf planet à la Pluto – isn't a frequent visitor. Located beyond Neptune, its extreme orbit ...

These icy bodies orbit the sun just like the major planets, yet they follow their own rules, often traveling along elongated ...

Pluto has long been one of the most debated celestial bodies in our solar system. Once classified as the ninth planet, it was redefined in 2006 as a dwarf planet, a decision that still sparks ...

No longer a planet but not forgotten, Pluto’s colors, captured by NASA almost 10 years ago, continue to dazzle among the collection of colorful celestial objects only seen in the solar system. Since ...

This is an image of Ceres, the nearest dwarf planet to Earth in the solar system. A new dwarf planet extremely far from the sun may have just been discovered. Credit: NASA / JPL-Caltech / UCLA / MPS / ...

Before Pluto was discovered, it was predicted. Astronomers had observed that massive objects can affect the orbits of their neighbors and, after seeing deviations in the orbits of Uranus and Neptune, ...

Astronomers using the Hubble Space Telescope have discovered a fourth moon orbiting Pluto. Pluto - for the record - is still classified as a dwarf planet. Astronomer Larry Wasserman of Lowell ...