Portrait of Edmond Halley Reprinted by permission from the Royal Society Library, London, England.

Edmond Halley was an English astronomer who lived between 1656-1742. Using historical records, his own observations, and Newton's universal law of gravitation, he reasoned that the comets which had appeared in 1456, 1531, 1607, and 1682, were one and the same. He then predicted the comet's return about every 76 years. Although Halley died in 1742, the comet reappeared 16 years later, and today bears his name.

In addition to his work on comets, Halley studied the Earth's weather and magnetic field, and the ocean's tides.