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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 ...

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 ...

(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 ...

Pluto, discovered 90 years ago on Feb. 18, 1930, was long considered the solar system's ninth planet. Although small, it orbits the sun and has the spherical shape required to be considered a planet.

Nine years, 3 billion miles, and $700 million later, we are finally getting the very first high resolution photos of Pluto, thanks to a NASA spacecraft called New Horizons. It’s a pretty small planet ...

Pluto was relegated to the catalog of minor planets, a major planet no more. Still, astronomers admitted that they knew very little about Pluto, which many believed was nothing more than a very cold, ...