Pluto's days, though they drag on a bit at around 153 hours, are nothing compared to its years. Pluto's orbit takes 248 Earth ...

What was discovered in Flagstaff, Arizona, and killed off in Prague? If you answered "Pluto's planethood," your grasp of the astronomical is excellent. Feb. 18 marks the 95th anniversary of the ...

PHOENIX – The Pluto Discovery Telescope at Lowell Observatory has reopened for the first time in a year after undergoing renovations. The telescope in Flagstaff was made famous on Feb. 18, 1930 when ...

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 ...

Pluto was the little planet that could — until it couldn’t. Discovered in 1930 at Lowell Observatory in Flagstaff, Arizona, ...

On January 5, 2005, astronomers at NASA discovered Eris, the second-largest dwarf planet in the solar system. Eris is just ...

FLAGSTAFF, Ariz. (AP) — The observatory where Pluto was discovered is taking full advantage of a flyby of the icy dwarf planet Tuesday with astronomy-themed face painting, an extra Pluto presentation ...

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 ...

FLAGSTAFF, Ariz. It's been 75 years since the discovery of Pluto, but it remains a mystery. Perhaps in another 10 years some of its secrets will be revealed when a space probe gets close enough for a ...

(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 ...