Edmond Halley (1656 - 1742) was an English astronomer, mathematician, and geophysicist best known for computing the orbit of the comet that now bears his name and correctly predicting its return.[1] A wide-ranging natural philosopher, he also made lasting contributions to geophysics, meteorology, and the study of mortality, and served as the second Astronomer Royal.
Early life and education
Halley was born on 8 November 1656 in Haggerston, near London, into a prosperous family. He was educated at St Paul's School and then at The Queen's College, University of Oxford, where he displayed an early aptitude for astronomy and mathematics.[2] He left Oxford before completing his degree in order to travel to the remote South Atlantic island of Saint Helena.
Cataloguing the southern skies
From Saint Helena, Halley observed and catalogued the stars of the southern hemisphere that could not be seen from Europe, publishing his Catalogus Stellarum Australium in 1678. The achievement earned him election as a Fellow of the Royal Society at the age of twenty-two, an unusually young age for the honour.[1]
Halley's Comet
Applying Isaac Newton's laws of gravitation, Halley calculated the orbits of numerous comets and concluded that the bright comets recorded in 1531, 1607, and 1682 were in fact a single body returning periodically. In 1705 he predicted that it would reappear around 1758.[3] Although he did not live to witness the event, the comet returned close to his forecast and was named in his honour, becoming the first comet recognised to be periodic.
Collaboration with Newton
Halley played a decisive role in the appearance of one of the most important works in the history of science. He encouraged Newton to set down his theory of universal gravitation and personally financed the printing of the Philosophiae Naturalis Principia Mathematica (1687) at his own expense, ensuring that it reached publication.[1]
Later career and legacy
Halley's interests ranged far beyond astronomy. He produced one of the earliest charts of the trade winds and monsoons, mapped the variation of Earth's magnetic field across the oceans, and compiled a table of mortality for the city of Breslau that became an early foundation of actuarial science. He also proposed using transits of Venus to measure the distance from the Earth to the Sun. In 1720 he was appointed the second Astronomer Royal, a position he held until his death at Greenwich on 14 January 1742.[4]
