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. He reasoned that the same comet which he saw in 1682 had appeared before and predicted that it would appear again, about every 76 years. Although Halley died in 1742, the comet reappeared 16 years later and was named after him.

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