Pluto's discovery was widely celebrated, especially in the U.S. After all, it was the first planet discovered in the new world, and America needed the win in 1930. "I think because it was discovered ...

Once the quirky underdog of our solar system, Pluto held planetary status until 2006, when it got a cosmic demotion that still stings space fans. Discovered in 1930, Pluto was the ninth planet for ...

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

Pluto may be a “dwarf” planet, but it is still a planet. In 2006, the International Astronomical Union, responding to the discovery of several Pluto-like objects in the Kuiper Belt beyond Neptune, ...

Pluto, discovered in 1930, was once considered the ninth planet in our solar system. In 2006, the International Astronomical Union reclassified Pluto as a dwarf planet because it doesn't meet all the ...

(Correction: An earlier version of this story misstated how far Pluto is from the sun. The correct number is 3.7 billion miles.) What was discovered in Flagstaff, Arizona, and killed off in Prague? If ...

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 ...

PRAGUE, Czech Republic — Leading astronomers declared today that Pluto is no longer a planet under historic new guidelines that downsize the solar system from nine planets to eight. After a tumultuous ...

In 2006, updated research led to Pluto being controversially demoted to dwarf planet status by the International Astronomical Union. The reasoning was that Pluto's location in the far-flung ...

It's going on two years since the International Astronomical Union rewrote its definition of a planet and busted Pluto down to something it called a "dwarf planet." But it's not a done deal, says Mark ...