Babcock invented and built a number of astronomical instruments, and in 1953 was the first to propose the idea of adaptive optics.
[3] Babcock's 1938 doctoral thesis contained one of the earliest indications of dark matter.
He reported measurements of the rotation curve for the Andromeda galaxy (M31) which suggested that the mass-to-luminosity ratio increases radially.
[4] He, however, attributed it to either absorption of light within the galaxy or modified dynamics in the outer portions of the spiral and not to any form of missing matter.
It was not until the 1970s and the work of Rubin and Ford that Babcock's rotation curve of M31 was fully accepted as an indication of a mass or gravity problem in spiral galaxies.