(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?

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 ...

Furthermore, the collision deposited substantial internal heat into both bodies, potentially influencing Pluto’s geological evolution and supporting theories of a subsurface ocean. This heat ...

The controversy endures over Pluto's true status, but the solar system underdog continues to capture hearts across the globe. Clyde Tombaugh didn't set out to discover Pluto when he sent his ...

An 11-year-old English schoolgirl, Venetia Burney, suggested the name Pluto, the god of the underworld. Tombaugh’s newfound fame earned him a scholarship to the University of Kansas, where he ...

Astronomer Percival Lowell founded his Arizona stargazing lab in 1894 to aid in his search for life on Mars. While that quest is still ...

NASA's New Horizons spacecraft conducted the first and only flyby of the Pluto system, culminating at the closest approach of that distant world in July 2015. Sailing onward, the probe carried out ...