In 2006, the International Astronomical Union stopped classifying Pluto as our solar system’s ninth planet and demoted its ...

One Pluto year equals 248 Earth years. At 1473 miles in diameter—about half the width of the United States—Pluto is the ...

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 ...

song, Interplanet Janet. Upon the discovery of its existence in 1930, Pluto enjoyed decades of special status as one of the solar system's planets. Then, in the summer of 2006, Pluto was demoted.

Pluto, humanity's favorite dwarf planet, is getting some high-profile allies. "Star Trek" actor William Shatner wants to use ...

There’s a new frozen oddball orbiting the Sun, and it’s not your average space rock. It’s a planet—a minor one, to be ...

This sparked debate about Pluto's status in the planetary canon, which came to a head at a 2006 meeting in Prague. That year, the IAU tasked a small committee with creating a working definition of ...

Scientists believe such an extreme orbit means the object was pushed and pulled by the gravity of giant planets like Jupiter ...

(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?

Despite the change, Pluto remains a beloved celestial body, and some astronomers still debate whether it should regain its planetary status. Yes. Clyde Tombaugh discovered Pluto on Feb. 18 ...