Charles Greeley Abbot

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Charles G. Abbot, at the 9th Annual Aircraft Engineering Research Conference, 1934

Charles Greeley Abbot (May 31, 1872 Wilton, NH – December 17, 1973, Washington D.C.) was an American astrophysicist, astronomer and Secretary of the Smithsonian Institution. He was born in Wilton, New Hampshire.

[edit] Life

Abbot graduated from MIT in 1894 with a degree in chemical physics. Samuel Pierpont Langley was looking for an assistant at the Smithsonian Astrophysical Observatory, and hired Abbot in 1895 because of his skill at laboratory work, despite his lack of experience in astronomy.

He became acting director in 1896 and director in 1907. He was also secretary of the Smithsonian Institution from 1928 to 1944, when he became a research associate.

Langley began to focus on aeronautics experiments, and Abbot took responsibility for the observatory's solar observations. He designed and built devices for measuring solar radiation, including a greatly improved bolometer which was used to measure the Sun's inner corona at the 1900 solar eclipse in Wadesboro, North Carolina.

Langley died in 1906. Abbot succeeded him as director of the SAO, and Charles Walcott became Smithsonian secretary. Abbot soon used improved techniques to come up with a more accurate value of 1.93 cal/cm²/min for the solar constant (the modern value is measured in watts per square meter).

In 1918 Abbot became Assistant Secretary of the Smithsonian. He succeeded Walcott as Secretary in 1928, and guided the Smithsonian through turbulent times during the Great Depression and World War II. He retired as both SAO director and Smithsonian Secretary in 1944, being the first Smithsonian Secretary not to die in office.

He delegated the National Museum largely to his Assistant Secretary, Alexander Wetmore, who succeeded him as Secretary in 1944.

[edit] Awards

Abbot won the Henry Draper Medal of the National Academy of Sciences in 1910 and the Rumford Prize of the American Academy of Arts and Sciences in 1915.

[edit] Studies

Abbot pushed to provide funding to rocket pioneer Robert Goddard during World War I, but to his disappointment this was canceled after the end of the war.

Abbot, like Langley, pursued the idea that the Sun's radiation was variable and that this variability could influence weather. He persistently searched for variations in the solar constant, hoping that these could be used for weather forecasting, and believed that he had detected such variations, on the order of 3% to 10%. However, modern measurements of greater accuracy indicate that such variability does not occur, apart from tiny variations due to sunspots and faculae.

He completed the mapping of the infrared solar spectrum and carried out systematic studies of variation in solar radiation, its relation to the sunspot cycle, and its effect on weather variation. He also studied the nature of atmospheric transmission and absorption. Abbot perfected various standardised instruments now widely used for measuring the sun's heat, and he invented devices utilizing solar energy.

Abbot crater on the Moon is named after him; an exception was made and it was named for him while he was still alive. He obtained his last patent at the age of 101, the oldest inventor to ever receive a patent.

[edit] External links

• National Academy of Sciences biography
• QJRAS 18 (1977) 136
• The University of Wisconsin Digital Collections Center presents The Smithsonian Scientific Series and the following digitized articles originally published by C.G. Abbot: Abbot, Charles Greeley The sun and the welfare of man (1938), Abbot, C. G. (Charles Greeley), 1872 Great inventions (1932), Bishop, Carl Whiting, 1881-1942; Abbot, Charles Greeley; Hrdlicka, Aleš Man from the farthest past (1930).