It’s a small world after all, because today, we’re shrinking Earth to the size of Pluto. But if our planet was this tiny, how ...

The International Astronomical Union declared that Pluto only fulfills two of the three criteria for a full-size planet. Pluto, discovered 90 years ago on Feb. 18, 1930, was long considered the solar ...

(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 ...

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 ...

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NASA chief Jared Issacman appears to be among those who support Pluto being reclassified as a planet. Could President Trump ...

Arizona has a new state emblem — and it's one that has been a source of controversy among scientists for years. Gov. Katie Hobbs signed a bill on Friday designating Pluto — once considered the ninth ...