CAPE CANAVERAL, FL -- Come Tuesday, Clyde Tombaugh will pass within 7,800 miles of the icy world he discovered 85 years ago. His ashes are flying on NASA's New Horizons spacecraft on humanity's first ...

For generations Pluto stood as the mythic ninth planet until a scientific revolution shattered that legacy and transformed it ...

The International Astronomical Union declared that Pluto only fulfills two of the three criteria for a full-size planet. Pluto, discovered 90 years ago on Feb. 18, 1930, was long considered the solar ...

Today, the dwarf planet Pluto orbits the sun from the edge of our solar system and its surface temperature is an inhospitable negative 378 to negative 396 degrees Fahrenheit. But a new study suggests ...

January 5, 2005, is an astronomical anniversary that is not really marked but should be. It saw the discovery of dwarf planet ...

The science community may be ecstatic over the discovery of a ninth planet, but the former planet "Pluto" had a totally different reaction. Hours after scientists announced there's solid evidence of ...

Pluto was reclassified as a dwarf planet in 2006 when the IAU redefined what it means to be a planet, declaring that a planet must be a celestial body that orbits the sun, is round or nearly round and ...