United States. Twenty-three-year-old Clyde Tombaugh discovered Pluto from the Lowell Observatory in Arizona, as part of the search for Planet X launched in 1905 by American billionaire Percival Lowell. He did so by comparing two images, among tens of thousands of others analyzed, and discovered a tiny, faint dot that had moved slightly. The name was chosen by an English girl, Venetia Burney, who suggested Pluto, after the god of the underworld. It was visited by the American probe New Horizons on July 14, 2015, after the cancellation of the Voyager 3 and 4 missions that would have visited it in the 1980s.
