Jeremiah Horrocks

(also Horrox). Born circa 1617; died 1641. English astronomer.

Horrocks introduced improvements in the theory of lunar motion. Even before I. Newton’s discovery of the law of universal gravitation, he had conjectured that the disparities in the lunar motion were the result of the perturbing influence of the sun, and he noted several irregularities in the motions of the Saturn and Jupiter. Horrocks calculated in advance the transit of Venus across the sun’s disk (1639) and was the first to observe the phenomenon.