Joseph loves History, Anthropology, Astronomy and Science, and they have been talking about Edmond Halley, the astronomer, geophysicist, mathematician, meteorologist, and physicist who was born on a day like today in 1742.
Edmond or Edmund Halley, (29 October 1656-14 January 1742) was an English astronomer, geophysicist, mathematician, meteorologist, and physicist.
He was the second Astronomer Royal in Britain, succeeding John Flamsteed in 1720.
From an observatory he constructed on Saint Helena, Halley recorded a transit of Mercury across the Sun. He realised a similar transit of Venus could be used to determine the size of the Solar System. He also used his observations to expand contemporary star maps.
He aided in observationally proving Isaac Newton's laws of motion, and funded the publication of Newton's influential Philosophiæ Naturalis Principia Mathematica. From his September 1682 observations, he used the laws of motion to compute the periodicity of Halley's Comet in his 1705 Synopsis of the Astronomy of Comets. It was named after him upon its predicted return in 1758, which he did not live to see.
Beginning in 1698, he made sailing expeditions and made observations on the conditions of terrestrial magnetism. In 1718, he discovered the proper motion of the fixed stars.
More information: BBC
Halley was born in Haggerston in Middlesex. His father, Edmond Halley Sr., came from a Derbyshire family and was a wealthy soap-maker in London. As a child, Halley was very interested in mathematics. He studied at St Paul's School where he developed his initial interest in astronomy, and from 1673 at The Queen's College, Oxford. While still an undergraduate, Halley published papers on the Solar System and sunspots.
While at the University of Oxford, Halley was introduced to John Flamsteed, the Astronomer Royal. Influenced by Flamsteed's project to compile a catalogue of northern stars, Halley proposed to do the same for the Southern Hemisphere.
In 1676, Halley visited the south Atlantic island of Saint Helena and set up an observatory with a large sextant with telescopic sights to catalogue the stars of the Southern Hemisphere.
While there he observed a transit of Mercury across the Sun, and realised that a similar transit of Venus could be used to determine the absolute size of the Solar System.
Halley spent most of his time on lunar observations, but was also interested in the problems of gravity. One problem that attracted his attention was the proof of Kepler's laws of planetary motion.
In August 1684, he went to Cambridge
to discuss this with Isaac Newton, much as John Flamsteed had done four
years earlier, only to find that Newton had solved the problem, at the
instigation of Flamsteed with regard to the orbit of comet Kirch,
without publishing the solution.
More information: Space
Halley asked to see the calculations and was told by Newton that he could not find them, but promised to redo them and send them on later, which he eventually did, in a short treatise entitled, On the motion of bodies in an orbit.
Halley recognised the importance of the work and returned to Cambridge to arrange its publication with Newton, who instead went on to expand it into his Philosophiæ Naturalis Principia Mathematica published at Halley's expense in 1687.
Halley's first calculations with comets were thereby for the orbit of comet Kirch, based on Flamsteed's observations in 1680-1. Although he was to accurately calculate the orbit of the comet of 1682, he was inaccurate in his calculations of the orbit of comet Kirch. They indicated a periodicity of 575 years, thus appearing in the years 531 and 1106, and presumably heralding the death of Julius Caesar in a like fashion in −44 (45 BCE). It is now known to have an orbital period of circa 10,000 years.
Halley succeeded John Flamsteed in 1720 as Astronomer Royal, a position Halley held until his death.
Halley died in 1742 at the age of 85. He was buried in the graveyard of the old church of St Margaret's, Lee at Lee Terrace, Blackheath. He was interred in the same vault as the Astronomer Royal John Pond; the unmarked grave of the Astronomer Royal Nathaniel Bliss is nearby.
His original tombstone was transferred by the Admiralty when the original Lee church was demolished and rebuilt –it can be seen today on the southern wall of the Camera Obscura at the Royal Observatory, Greenwich. His marked grave can be seen at St Margaret's Church, Lee Terrace.
More information: EarthSky
Edmond Halley
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