Edmond Halley

born in 1656, died in 1742 (in Greenwich).

English scientist in astronomy and mathematics and namesake of the famous comet.

Halley was son of a prosperous merchant and attended Queen's college in Oxford, leaving as an undergraduate in 1676. He travelled to the island of St Helena in the South Atlantic, which later became known to be Napoleon's exile, trying to chart the sky of the South. 341 stars were mapped during this 2-year-observation, which nobody had done before. Returning to England and publishing his work, Halley finally got a master's degree and also became member of the Royal Society like Christopher Wren and Robert Hooke.

In 1684, after having a debate with Hooke and Wren about the planets' movement, he went to Cambridge to visit Isaac Newton and asked him for his opinion on that matter. Halley learned that Newton had already worked on the topic of gravitation leading to his later famous law of gravity. He argued Newton into writing and publishing his works. Therefore, Halley secured the finances of this project which in 1687 became published and known as Newton's Principia or Mathematical Principles of Natural Philosophy.

Being 39 years old, Halley got more interested in comets, believing that they were also influenced by the forces of gravity. By comparing the routes of comets of the past, he found out that these seemingly different comets were one and the same. In 1705 then, he figured correctly that this comet would reappear in 1758. Today it is known as Halley's comet.

By then, he had already been professor of astronomy at Oxford for two years. Furthermore, Halley discovered the proper movements of the stars (1718) as well as the fact that the mean motion of the moon accelerates. Meanwhile in 1720, being promoted the second Astronomer Royal, he began observations of the sun and the moon which should take 18 years.

He also had an important position in the transformation of Royal Society, then a social club, into a scientific institution.

He participated in scientific meetings until he died in Greenwich aged 86. His last work Tabulae astronomicae was released after his death in 1749.

Sources

"Edmond Halley." The Columbia Encyclopedia, Sixth Edition. 2008. Encyclopedia.com. 12 Jul. 2009 [1]

"Halley, Edmond." A Dictionary of Astronomy. 1997. Encyclopedia.com. 12 Jul. 2009 [2]

"Halley, Edmond (1656-1743)." World of Earth Science. The Gale Group, Inc. 2003. Encyclopedia.com. 12 Jul. 2009 [3]

John Cannon. "Halley, Edmond." The Oxford Companion to British History. Oxford University Press. 2002. Encyclopedia.com. 12 Jul. 2009 [4]