This Day in History: 1930-02-18
In 1930 Pluto was discovered at the Lowell observatory in Arizona, US by astronomer Clyde W. Tombaugh. The ninth planet was first proposed by Percival Lowell, an American businessman who became an accomplished astronomer. He predicted a ninth planet or ‘planet X’ as he called it from the perturbations (a slight wobble or deviation) of the orbital path of Uranus and Neptune (These wobbles are normally caused by the gravitational pull of foreign bodies). He searched for many years at the Lowell observatory, which he founded, but was unable to find planet X. After his death, as lens technology improved the observatory were able to install a larger, more powerful telescope which Tombaugh used to continue the search. On this day in 1930 Tombaugh found the tiny planet but the observatory waited until the anniversary of Lowell’s birth (13th of March) to announce their findings.
