1693-1762

English astronomer renowned for discovering stellar aberration—apparent displacement of a star's position due to the combined velocity of Earth and starlight. Bradley exploited this effect to estimate the speed of light, thus providing the first direct evidence of Earth's motion. Correcting for aberration, his extensive astronomical observations were more accurate than those of his predecessors. Bradley discovered the nutation of Earth's axis, measured Jupiter's diameter, and succeeded Edmond Halley as the third Astronomer Royal.