1656–1742, English astronomer
Best remembered for the comet that bears his name, Edmond Halley was one of the great scientists of all time. He discovered the proper motion of stars, made important studies of the moon's motion, and his investigations of the Earth's magnetic field and of tides were unrivalled for centuries.
Halley played a crucial role in the Newtonian revolution in the natural sciences. It was Edmond Halley who set the question that led Sir Isaac Newton to write the Principia, and who edited, paid for, and reviewed it.
Halley's prediction of the transit of Venus led to Captain Cook's voyage to Tahiti and to an accurate calculation of the distance between the Earth and Sun.
Halley used his knowledge of erosion, and measurements of salt in ocean water, to come up with an early estimate of the age of the planet Earth itself.
As a young man, he sailed to St. Helena to chart the unmapped stars of the Southern Hemisphere. Moreover, Halley knew the leading artists of his age--Wren, Pepys, Handel, Purcell, and John Dryden--and he travelled widely throughout Europe, meeting numerous fellow scientists and serving on a variety of diplomatic missions. He even spent a number of adventurous years as commander of a Royal Naval warship.