The discovery of Pluto, the ninth…

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Thursday, March 13, 1930: The discovery of Pluto, the ninth planet, was officially announced on this date, which was Percival Lowell’s birthday. Lowell was founder of Lowell Observatory in Flagstaff, Arizona, where Clyde W. Tombaugh discovered Pluto on February 18, 1930. (Much later, Pluto’s “planet” designation changed!).