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 ...

"Pluto was found really close to where Lowell thought a planet should be, but it's also a great example of serendipity in science," Schindler said. "When Lowell was doing his work, there was an ...

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 decades, Pluto was celebrated as the ninth planet of our solar system. However, in 2006, the International Astronomical Union (IAU) redefined what constitutes a planet, leading to Pluto’s ...

Claims that the Solar System has a tenth planet are bolstered by the finding by a group led by Bonn astrophysicists that this alleged planet, announced last summer and tentatively named 2003 UB313, is ...

(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 ...

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

For the first time, NASA’s Hubble Space Telescope has seen distinctly the “tenth planet,” currently nicknamed “Xena,” and has found that it is only slightly larger than Pluto. Though previous ...

The year was 2015. After traveling billions and billions of miles through the Erebus, New Horizons encounters the boatman, and the somber lord of the departed. The spacecraft could have been called ...