Englishastronomer. In collaboration with Samuel Molyneux (1689–1728) he attempted to detect stellar parallax, but instead discovered the annual aberration of starlight. This discovery, announced in 1728, was the first direct observational verification that the Earth orbits the Sun. From the amount of aberration he calculated the speed of light to within 2% of the true value. In 1742 Bradley became the third Astronomer Royal. He subsequently discovered the nutation of the Earth's axis, announced in 1748.
Subjects: Astronomy and Astrophysics.