Sydney Chapman was born on January 28, 1888 near Manchester, England. He studied engineering at the University of Manchester, but obtained a degree in mathematics as well. Chapman then attended Trinity College, Cambridge University to further study mathematics, graduating in 1910.
Chapman worked at the Greenwich Observatory and over the course of his career, had faculty positions at Manchester, Cambridge, and Oxford Universities. He made important contributions in thermal diffusion, the kinetic theory of gasses, and astronomy. To students of probability, his named is linked with Andrei Kolmogorov through the famous Chapman-Kolmogorov equation for Markov processes. Sydney Chapman died on June 16, 1970 in Boulder, Colorado, USA.