November 5, 2012
On Nov. 5, 1906, Fred Lawrence Whipple was born in the commercial trading town of Red Oak, Iowa. His more than 70 years of astronomical observations and scientific work changed our understanding of comets and made space travel safer.
Whipple started his academic career in mathematics and graduated from UCLA in 1927, but he became fascinated with physics and astronomy and got his doctorate at the University of California, Berkley. He immediately headed east to accept a job at the Harvard College Observatory in 1931.
When he passed away on Aug. 30, 2004, the Harvard Gazette obituary quoted Charles Alcock, director of the Harvard-Smithsonian Center for Astrophysics, "Fred Whipple was one of those rare individuals who affected our lives in many ways. He predicted the coming age of satellites, he revolutionized the study of comets, and as director of the Smithsonian Astrophysical Observatory, he helped form the Harvard-Smithsonian Center for Astrophysics."
His astrophysical talents were quickly apparent. While in graduate school, he was part of a team that mapped the orbit of Pluto (when it was still considered a planet). When he started at the Harvard observatory he was primarily interested in meteors, and helped prove that meteors originated within the solar system and were not interstellar visitors.
In 1933, he discovered his first comet, designated 36P/Whipple, a periodic comet, and also the asteroid 1252 Celestia. He discovered, or co-discovered, five more comets during his research.
He interrupted his solar system research during World War II to work with the military efforts, primarily on radar detection counter-measures. He co-developed a chaff-cutter device that "transformed 3 ounces of aluminum foil into 3,000 half-wave dipoles." Chaff confuses enemy radar systems to protect airplanes from attack. (Astronomy magazine obituary)
After the war Whipple returned to his research, and began to think about man’s eventual forays into space. In 1946, he invented the Whipple Shield, a “meteor bumper,” to protect space vehicles from meteor impacts. Improved versions of the shield are still used today.
He was one of a handful of scientists to predict the emergence of artificial satellites. They organized a global network of amateur astronomers that would track satellites, whenever they might be launched. Sputnik I was launched on Oct. 4, 1957, and Whipple’s network, “Moonwatch,” was the only non-Russian source of information about the satellite; the U.S. government was not prepared to release any information.
In 1950, Whipple published his theory that a comet nucleus was an icy conglomerate, not “flying sandbanks” as previously thought. And the composition, when heated by the solar wind, is what caused the variability of comet orbits. Observers had been mystified by the inaccuracy of mathematical predictions of the reappearance of comet. In 1910, Halley’s Comet returned three days later than expected. But the “dirty snowball” theory, explained how the explosive expansion of methane, ammonia and carbon dioxide that Whipple postulated would alter orbits.
Astronomy magazine quoted Brian Marsden, director of the Minor Planet Center, in their obituary, “The [icy conglomerate model] was one of the most important contributions to solar system studies in the 20th century." Whipple’s papers on his theories are still among the most cited scientific papers.
He was still engaged in research as late as 1999, when he joined the CONTOUR mission. He was 93, and still a mind to be reckoned.