Fred Lawrence Whipple (November 5, 1906 – August 30, 2004) was an American astronomer.

He is best known for writing an influential paper in Astrophysical Journal in 1950, in which he proposed the "icy conglomerate" theory of comet composition (later called the "dirty snowball" theory). The basic features of this theory were later confirmed, however the exact amount (and thus the importance) of ices in a comet is an active field of research, with most of the recently obtained data pointing to a low contribution of ices to a comet's mass (dubbed the "icy dirtball" theory).

Whipple, the son of a farmer, was born November 5, 1906, in Red Oak, Iowa. An early bout with polio ended his ambition of being a professional tennis player. Whipple studied at Occidental College in southern California, then majored in mathematics at the University of California at Los Angeles. A class in astronomy turned him in that direction, and he received a doctorate in that subject in 1931 from the University of California at Berkeley. While in graduate school, he helped map the orbit of the newly discovered planet Pluto.

He joined Harvard College Observatory in 1931 and studied the trajectories of meteors, confirming that they originated within the solar system rather than from interstellar space.

In 1933, he discovered the periodic comet 36P/Whipple and the asteroid 1252 Celestia. He also discovered or co-discovered five other non-periodic comets, the first of which was C/1932 P1 Peltier-Whipple, independently discovered by the famed amateur astronomer Leslie Peltier.

During World War II, he invented a device for cutting tinfoil into chaff to confuse enemy radar tracking Allied aircraft. He was awarded a Certificate of Merit for this in 1948.

He also invented a "meteor bumper" or "Whipple shield", which protects spacecraft from impact by small particles by vaporizing them.

In 1955 he became director of the Smithsonian Astrophysical Observatory (SAO), remaining in this post until 1973.

He anticipated the era of artificial satellites and organized the "Moonwatch" group to track them. His group was the only one prepared and ready to make observations when the Soviet Union unexpectedly launched Sputnik I in 1957.

Whipple died in 2004, aged 97.

Honors

• Distinguished Federal Civilian Service Award, by US President John F. Kennedy (1963)
• Gold Medal of the Royal Astronomical Society (1983)
• Bruce Medal of the Astronomical Society of the Pacific (1986)
• Henry Norris Russell Lectureship of the American Astronomical Society (1987)

• Asteroid 1940 Whipple
• Whipple Observatory on Mount Hopkins in Arizona
• Whipple shield

Notes

1. Fred L. Whipple, "A Comet Model" (two parts), Astrophys. J. 111(1950), p. 375 and 113(1951), p. 464; Online versions Part I, Part II
2. Horst Uwe Keller at al., "Deep Impact Observations by OSIRIS Onboard the Rosetta Spacecraft", Science 310(2005), p. 281; online abstract

External links

• Bruce Medal entry with picture
• Report of his death (BBC)
• Report of his death (CNN)
• Astronomy.com obituary
• Harvard-Smithsonian Center for Astrophysics press release

1906 births | 2004 deaths | American astronomers | Planetary scientists | Asteroid discoverers

Фред Уипъл | Fred Whipple | Fred Lawrence Whipple | Fred Whipple | フレッド・ホイップル | Fred L.Whipple | 弗雷德·惠普尔