| On This Day in American History |
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On February 18, 1930, Pluto is discovered by astronomer Clyde W. Tombaugh at the Lowell Observatory in Flagstaff, Arizona. The existence of Pluto had long been hypothesized because the orbits of Neptune and Uranus were known to wobble, likely under the influence of another body. Named after the Roman god of the underworld, Pluto is about 4 billion miles from the sun, and it takes 248 years to complete one orbit of the sun. Long considered the ninth planet, scientists in 2006 decided it did not qualify as a planet because its orbit overlapped, at times, with Neptune’s. |
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