Clyde Tombaugh discovered Pluto in 1930 at Lowell Observatory in Flagstaff. Here's how Pluto won - and lost - its planetary ...

For decades, it captivated imaginations with its icy surface and distant orbit beyond Neptune. But in 2006, Pluto’s planetary reign came to an end when the International Astronomical Union ...

“New Horizons shattered a major paradigm of planetary science,” says Alan Stern, the mission’s principal investigator. “Pluto turns out to have as much complexity as Mars or Earth, so much so that I ...