William Henry Pickering

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William Henry Pickering
Pickering William Henry 02598v.jpg
Pickering in 1909
Born February 15, 1858
Boston, Massachusetts
Died January 16, 1938(1938-01-16) (aged 79)
Mandeville, Jamaica
Fields Astronomy
Notable awards Lalande Prize (1906)

William Henry Pickering (February 15, 1858 – January 16, 1938) was an American astronomer and the brother of Edward Charles Pickering. He was elected a Fellow of the American Academy of Arts and Sciences in 1883.[1]


He discovered Saturn's ninth moon Phoebe in 1899 from plates taken in 1898. He also believed he had discovered a tenth moon in 1905 from plates taken in 1904, which he called "Themis". For this discovery he was awarded the Lalande Prize of the French Academy of Sciences in 1906. "Themis" was later shown to not exist.

Following George Darwin, he speculated in 1907 that the moon was once a part of the earth and that it broke away where now the Pacific Ocean lies. He also proposed some sort of continental drift (even before Alfred Wegener) and speculated that America, Asia, Africa, and Europe once formed a single continent, which broke up because of the separation of the moon. [2]

In 1908 he made a statement regarding the possibility of airplanes that had not yet been invented, saying that "a popular fantasy is to suppose that flying machines could be used to drop dynamite on the enemy in time of war".[citation needed]

He led solar eclipse expeditions and studied craters on the Moon, and hypothesized that changes in the appearance of the crater Eratosthenes were due to "lunar insects".[3] He also claimed to have found vegetation on the moon.[4]

In 1919, he predicted the existence and position of a Planet X based on anomalies in the positions of Uranus and Neptune but a search of Mount Wilson Observatory photographs failed to find the predicted planet. Pluto was later discovered at Flagstaff by Clyde Tombaugh in 1930, but in any case it is now known that Pluto's mass is far too small to have appreciable gravitational effects on Uranus or Neptune, and the anomalies are accounted for when today's much more accurate values of planetary masses are used in calculating orbits. When the planet was named, he interpreted its symbol as a monogram referring to himself and Lowell by the phrase "Pickering-Lowell".[5]

Pickering constructed and established several observatories or astronomical observation stations, notably including Percival Lowell's Flagstaff Observatory. He spent much of the later part of his life at his private observatory in Jamaica. He produced a photographic atlas of the Moon: The Moon : A Summary of the Existing Knowledge of our Satellite — New York: Doubleday, Page & Company, 1903.

He won the Prix Lalande in 1905 and the Prix Jules Janssen in 1909.[6] The asteroid 784 Pickeringia, and the craters Pickering on the Moon and Pickering on Mars, are jointly named after him and his brother Edward Charles Pickering.


  1. ^ "Book of Members, 1780-2010: Chapter P". American Academy of Arts and Sciences. Retrieved 22 April 2011. 
  2. ^ Pickering, W.H (1907). "The Place of Origin of the Moon - The Volcani Problems". Popular Astronomy 15: 274–287. Bibcode:1907PA.....15..274P. 
  3. ^ Moore, Patrick (1999). The wandering astronomer. Bristol; Philadelphia: Institute of Physics Pub. ISBN 9780750306935. 
  4. ^ "SAYS 2 CROPS A DAY GROW ON THE MOON; Prof. Pickering Is Convinced Markings Are Caused by Vegetation in the Craters.FIELD PATTERNS TRACEDCriticises Astronomers for Assuming Life There Is Impossible--Easier to Study Than Mars. May Be Life in Low Form. Same Old Argument. The Southeastern Field. Arguing Like a Fish". The New York Times. October 9, 1921. 
  5. ^ Pickering W. H. (1930). "The discovery of Pluto". Monthly Notices of the Royal Astronomical Society 91 (1): 0812–0817. Bibcode:1931MNRAS..91..812P. doi:10.1093/mnras/91.7.812. 
  6. ^ "Pickering, William Henry". New International Encyclopedia 18. 1918. p. 605. 

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