His research interests were exceptionally broad but we can divide them into topics and rough periods when he was concentrating on these particular topics. First he studied stellar structure, including the theory of white dwarfs, from 1929 to 1939, then stellar dynamics from 1939 to 1943. Next he looked at the theory of radiative transfer and the quantum theory of the negative ion of hydrogen from 1943 to 1950, followed by hydrodynamic and hydromagnetic stability from 1950 to 1961.
Ang kanyang mga pananaliksik interes ay iba malawak ngunit kami ay maaaring hatiin ang mga ito sa mga paksa at magaspang panahon kapag siya ay concentrating sa mga partikular na paksa. Unang-aral siya sa bituin structure, kabilang ang mga teorya ng white dwarfs, 1929-1939, at pagkatapos ay sa bituin dinamika 1939-1943. Susunod na siya tumingin sa teorya ng namamanaag transfer at ang quantum theory ng mga negatibong Ion ng haydrodyen 1943-1950, sinusundan ng hydrodynamic at hydromagnetic katatagan 1950-1961.