These icy bodies orbit the sun just like the major planets, yet they follow their own rules, often traveling along elongated ...

Earth has a newly-discovered neighbor in the solar system. But the heavenly body – possibly a dwarf planet à la Pluto – isn't a frequent visitor. Located beyond Neptune, its extreme orbit ...

The heart's brightness arises from sunlight reflection, while red patches, formed by tholins, showcase Pluto's atmospheric ...

In 2006, the International Astronomical Union (IAU) voted on the definition of a planet. Famously, Pluto no longer met the criteria and was demoted to a dwarf planet. Things have been a bit of a mess ...

Pluto has long been one of the most debated celestial bodies in our solar system. Once classified as the ninth planet, it was redefined in 2006 as a dwarf planet, a decision that still sparks ...

In this except from "Space Camp," a special series from NPR science podcast Short Wave, host Regina Barber delves into Pluto's demotion from planet to dwarf planet. It's not exactly news to say that ...

No longer a planet but not forgotten, Pluto’s colors, captured by NASA almost 10 years ago, continue to dazzle among the collection of colorful celestial objects only seen in the solar system. Since ...

For many people, the definition of a planet was only made clear in 2006, when the spunky world Pluto was demoted from a planet to a dwarf planet. Now, a team of astronomers is pushing for “planet” ...

(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 ...