Halley, << HAL ee, >> Edmond (1656-1742), also spelled Edmund, was an English astronomer noted for his work on comets. He calculated the orbit of a comet he observed in 1682 and proved that it was the same one astronomers had seen in 1531 and in 1607. He predicted its return in 1758. The comet was sighted on Christmas Day of that year. This comet became known as Halley’s Comet. See Halley’s Comet .
Halley produced the first accurate map of the stars visible from the Southern Hemisphere. He proved that stars have proper motion—that is, they change position in relation to each other. Halley studied the orbit of the moon and the effect of the moon on ocean tides. He also determined an accurate way to measure the distance of the sun from the earth. This measurement was needed for determining the size of the solar system and the distances of other stars from the earth.
Halley was born in London on Nov. 8, 1656. He attended Oxford University and served as England’s astronomer royal from 1720 until his death on Jan. 14, 1742.
