There are only eight planets in the solar system. Better get used to it. The International Astronomical Union's members voted Thursday to accept a definition of the term "planet" that leaves tiny, ...

NASA's New Horizons spacecraft captured this high-resolution enhanced color view of Pluto that is inserted beneath the Short Wave logo. The image combines blue, red and infrared images taken by the ...

For many people, the definition of a planet was only made clear in 2006, when the spunky world Pluto was demoted from a planet to a dwarf planet. Now, a team of astronomers is pushing for “planet” ...

The debate over Pluto’s planetary status has been ongoing since its reclassification as a “dwarf planet” in 2006 by the International Astronomical Union (IAU). Recent discussions and new scientific ...

From the time of its discovery in 1930 until 1992, Pluto was a happy, full-fledged planet. A little odd maybe with its tipped, eccentric orbit and tiny size, but the ninth planet just the same. That ...

Though Pluto has formally been considered a dwarf planet for almost two decades, it still has many lessons left for planetary scientists —... Pluto isn’t a planet — but it gives us clues for how the ...