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 ...

(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 ...

A new formation theory for Pluto's moon Charon could explain why Pluto is geologically active. Illustration incorporates NASA New Horizons terrain imagery. Pluto — demoted to dwarf planets status in ...

Since Pluto remains in the sun’s orbit, it should be considered a planet due to the fact that it is still a part of the solar system. And since Pluto is still hanging on at the end of the system, it ...

The “demoted” dwarf planet Pluto and its largest moon Charon make an unusual pair, and for decades, scientists have been discussing how the binary system—in which each mutually orbits the other—came ...

What was discovered in Flagstaff, Arizona, and killed off in Prague? If you answered "Pluto's planethood," your grasp of the astronomical is excellent. Feb. 18 marks the 95th anniversary of the ...