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 ...

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 ...

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 ...

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

Billions of years ago, in the frozen edges of the solar system, a violent impact shaped one of space’s oddest pairs. Instead of a typical planet-moon setup, Pluto and Charon became a binary system.

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 ...