Pluto was discovered at Lowell Observatory in Flagstaff, Arizona in 1930 and was considered our ninth planet until 2006. The International Astronomical Union reclassified Pluto as a dwarf planet ...

Ever since the cameras of NASA's New Horizons mission discovered a large heart-shaped structure on the surface of the dwarf planet Pluto in 2015, this "heart" has puzzled scientists because of its ...

(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?

The findings are part of a study about Pluto and its internal structure published Monday in the journal Nature Astronomy. Previously, the team studied unusual features across the solar system ...

Pluto, discovered in 1930, was once considered the ninth planet in our solar system. In 2006, the International Astronomical Union reclassified Pluto as a dwarf planet because it doesn't meet all ...