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Halley, Edmund

        Science | Astronomers

Halley, Edmund (1656?1743), an English astronomer and scientist. He is best known for his studies of thehcomet that bears his name. He observed it in 1682, calculated its orbit, and predicted its reappearance. As he had foretold, the comet reappeared in 1758; this was the first time that the reappearance of a comet had been correctly predicted. COMET,

Halley was a friend of Isaac Newton, and it was at Halley's urging and expense that Newton's Principia, the treatise that formulated the laws of gravitation, was published. Halley was also an inventor; he built a successful diving bell and found a way to supply divers with compressed air. Diving Halley contributed to other fields as well, including meteorology, optics, magnetism, and mathematics. He published the first map of the winds on the earth's surface (1689) and was the first to attempt to establish tables of life expectancy (1693).

Halley was born in London. He attended Queen's College, Oxford. During 167678 he observed the stars of the Southern Hemisphere from the South Atlantic island of St. Helena. There he cataloged 341 starsthe first star chart made using a telescope.

Halley became a professor at Oxford in 1703. By comparing his star charts with ancient ones, in 1718 he showed that stars are not fixed in the heavens. Halley became astronomer royal in 1720 and spent 18 years studying the motion of the moon.