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BIO Magazine - Edmond Halley Δεκέμβριος 2015
Δεκέμβριος 2015 No38

BIO Biography

Edmond Halley
Edmond Halley

Early life

Halley was born in Haggerston, Shoreditch, England. 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, and from 1673 at The Queen's College, Oxford. While an undergraduate, Halley published papers on the Solar System and sunspots.[citation needed]

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.[5] While there he observed a transit of Mercury, and realised that a similar transit of Venus could be used to determine the absolute size of the Solar System.[6] He returned to England in May 1678. In the following year he went to Danzig (Gdańsk) on behalf of the Royal Society to help resolve a dispute. Because astronomer Johannes Hevelius did not use a telescope, his observations had been questioned by Robert Hooke. Halley stayed with Hevelius and he observed and verified the quality of Hevelius' observations. The same year, Halley published the results from his observations on St. Helena as Catalogus Stellarum Australium which included details of 341 southern stars.[7] These additions to contemporary star maps earned him comparison with Tycho Brahe: e.g. "the southern Tycho" as described by Flamsteed. Halley was awarded his M.A. degree at Oxford and elected as a Fellow of the Royal Society at the age of 22.

In 1686, Halley published the second part of the results from his Helenian expedition, being a paper and chart on trade winds and monsoons. In this he identified solar heating as the cause of atmospheric motions. He also established the relationship between barometric pressure and height above sea level. His charts were an important contribution to the emerging field of information visualization.

A 1702 printing of Halley's chart

In 1692, Halley put forth the idea of a hollow Earth consisting of a shell about 500 miles (800 km) thick, two inner concentric shells and an innermost core, about the diameters of the planets Venus, Mars, and Mercury.[13] He suggested that atmospheres separated these shells, and that each shell had its own magnetic poles, with each sphere rotating at a different speed. Halley proposed this scheme in order to explain anomalous compass readings. He envisaged each inner region as having an atmosphere and being luminous (and possibly inhabited), and speculated that escaping gas caused the Aurora Borealis.[14]

In 1693 Halley published an article on life annuities, which featured an analysis of age-at-death on the basis of the Breslau statistics Caspar Neumann had been able to provide. This article allowed the British government to sell life annuities at an appropriate price based on the age of the purchaser. Halley's work strongly influenced the development of actuarial science. The construction of the life-table for Breslau, which followed more primitive work by John Graunt, is now seen as a major event in the history of demography.

The Royal Society censured Halley for suggesting in 1694 that the story of Noah's flood might be an account of a cometary impact.[15]

Halley's grave

Exploration years

In 1698, Halley was given command of the Paramour, a 52 feet (16 m) pink, so that he could carry out investigations in the South Atlantic into the laws governing the variation of the compass. On 19 August 1698, he took command of the ship and, in November 1698, sailed on what was the first purely scientific voyage by an English naval vessel. Unfortunately problems of insubordination arose over questions of Halley's competence to command a vessel. Halley returned the ship to England to proceed against officers in July 1699. The result was a mild rebuke for his men, and dissatisfaction for Halley, who felt the court had been too lenient.[16] Halley thereafter received a temporary commission as a Captain in the Royal Navy, recommissioned the Paramour on 24 August 1699 and sailed again in September 1699 to make extensive observations on the conditions of terrestrial magnetism. This task he accomplished in a second Atlantic voyage which lasted until 6 September 1700, and extended from 52 degrees north to 52 degrees south. The results were published in General Chart of the Variation of the Compass (1701). This was the first such chart to be published and the first on which isogonic, or Halleyan, lines appeared.

Plaque in South Cloister of Westminster Abbey

The preface to Awnsham and John Churchill’s collection of Voyage and travels (1704), perhaps by John Locke or by Edmond Halley, made the link.[citation needed] It is not to Halley's credit that he failed to acknowledge Gregory's priority in this matter. In 1718 he discovered the proper motion of the "fixed" stars by comparing his astrometric measurements with those given in Ptolemy's Almagest. Arcturus and Sirius were two noted to have moved significantly, the latter having progressed 30 arc minutes (about the diameter of the moon) southwards in 1800 years.[19]

In 1720, together with his friend the antiquarian William Stukeley, Halley participated in the first attempt to scientifically date Stonehenge. Assuming that the monument had been laid out using a magnetic compass, Stukeley and Halley attempted to calculate the perceived deviation introducing corrections from existing magnetic records, and suggested three dates (AD 920, AD 220 and 460 BC), the earliest being the one accepted. These dates were wrong by thousands of years, but the idea that scientific methods could be used to date ancient monuments was revolutionary in its day.[20]

Halley succeeded John Flamsteed in 1720 as Astronomer Royal, a position Halley held until his death in 1742 at the age of 85. Halley was buried in the graveyard of the old church of St. Margaret (since rebuilt), at Lee, South London. He was interred in the same vault as Astronomer Royal John Pond; the unmarked grave of Astronomer Royal Nathaniel Bliss is nearby.[21]

Personal life

Halley married Mary Tooke in 1682 and settled in Islington. The couple had three children.

Halley's map of the path of the Solar eclipse of May 3, 1715 across England

Pronunciation

There are three pronunciations of the surname Halley. The most common, both in Great Britain[3] and in the United States,[4] is /hæli/. This is the personal pronunciation used by most Halleys living in London today.[22] The alternative /hli/ is often preferred for the man and the comet by those who grew up with rock and roll singer Bill Haley, who called his backing band his "Comets" after the common pronunciation of Halley's Comet in the United States at the time.[23] Colin Ronan, one of Halley's biographers, preferred /hɔːli/. Contemporary accounts spell his name Hailey, Hayley, Haley, Haly, Halley, Hawley and Hawly, and presumably pronunciations varied similarly.[24]

As for his given name, although the spelling "Edmund" is quite common, "Edmond" is what Halley himself used.[2]

http://en.wikipedia.org/wiki/Edmond_Halley

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