Americanastronomer. In the 1930s and 1940s he conducted photographic meteor patrols, and found that the Taurid meteor stream has the same orbit as Comet Encke. In 1949 he proposed an ‘icy conglomerate’ theory of comets (later dubbed the ‘dirty snowball’ model), according to which a comet's nucleus consists of frozen gases mixed with dust; this was borne out in 1986 when the Giotto space probe flew past the nucleus of Halley's Comet. Whipple discovered six comets, and studied planetary nebulae, flare stars, and stellar evolution.
Subjects: Astronomy and Astrophysics.