Edmond Halley

Second Astronomer Royal

Born: 8 November 1656 Haggerston, Middlesex (now part of London) England
Died: 14 January 1742
Buried: St Margaret's Churchyard, Lee (near Greenwich), London, England
Astronomer Royal: 1720 - 1742

Edmond Halley, b. Nov. 8 (Oct. 29, O.S.), 1656, d. Jan. 14, 1742, was an English astronomer who discovered the proper motion of stars and the periodicity of comets. His activities also ranged from studying archaeology to serving as deputy comptroller of the mint at Chester. He was an integral part of the English scientific community at the height of its creativity.

A graduate of Oxford, he became a member of the Royal Society at the age of 22. From the island of Saint Helena, he catalogued (1676-78) the positions of about 350 Southern Hemisphere stars and observed a transit of Mercury; he urged that the latter phenomenon and future transits of Venus be used to determine the distance of the Sun. He worked out a theory of cometary orbits, concluded that the comet of 1682 (which still bears his name) was periodic, and correctly predicted that it would return in 76 years. In 1710, comparing current star positions with those listed in Ptolemy's catalog, he deduced that the stars must have a slight motion of their own, and he detected this proper motion in three stars.

Halley was appointed Savilian professor of geometry at Oxford in 1704, and in 1720 he succeeded John Flamsteed as astronomer royal. At the Greenwich Observatory he used the first transit instrument and devised a method for determining longitude at sea by means of lunar observations.

Halley played an active role in the events and controversies of his time. He both morally and financially supported Isaac Newton, pacified the astronomer Johannes Hevelius regarding the disputed accuracy of methods for measuring stellar positions, and infuriated Flamsteed by scheming with Newton to publish Flamsteed's observations long before they were complete.

Halley was a major astronomer. He began observing seriously already as an undergraduate and published a paper on theoretical astronomy in the Philosophical Transactions at that time. He is known today primarily for A Synopsis of the Astronomy of Comets, 1705, but he made other important contributions: the catalogue of the southern skies (Catalogus stellarum australium, 1678), the method of measuring the astronomical unit via transits of Venus, the establishment of stellar motion and the secular acceleration of the moon.

• He published important editions of Apollonius and of other ancient geometricians as well as papers in pure mathematics.
• He is considered the founder of geophysics, especially for his paper on trade winds and his work on tides.
• He was one of the pioneers in social statistics by calculating annuities from the mortality tables of Breslau (1693).
• He was constantly concerned with the magnetism of the earth, and developed a general theory about this. He also experimented at determining the law of magnetic poles.
• He was concerned as well with weather, and published on the relation of barometric pressure to the weather.

Why is the comet named after Halley?

Edmond Halley was using Isaac Newton's ideas of gravitation to analyze the motion of bodies in the solar system. He noticed that the records for the bright comets of 1531, 1607, and 1682 showed that all three comets had very similar orbits. He drew the bold conclusion that all three were really the same comet, trapped by the gravitational pull of the outer planets, and predicted that the comet would return in 1758-59. The comet was found again on Christmas night 1758 and was then named in the late astronomer's honour. 

Halley's Comet has been know since at least 240 BC (and possibly 1059 BC). Its most famous appearance was in 1066 AD when it was seen right before the Battle of Hastings. It was named after  Halley, who calculated its orbit.

Halley's Comet put on bright shows in 1835 and in 1910.  Its return in 1986 was accompanied by space missions including the  Giotto mission to Halley's Comet.

Links

Comprehensive guide to Halley

More Edmond Halley links

The other Haley and his Comets

Bill Haley and the Comets famous Rock around the Clock

The Bill Haley and the Comets recording of "Rock Around the Clock," which topped the charts for eight weeks in 1955, is remembered as the beginning of the rock era. Though it also represented Haley's peak as a performer, his career had begun some time before and would continue for a long time after. Born in Michigan, Haley began leading Western swing bands under various names in the late '40s, slowly starting to incorporate elements of R&B. Soon after he began recording for Essex in the early '50s, his backup band was named the Comets.