Person: Halley, Edmond
Edmond Halley was an English astronomer who calculated the orbit of the comet now called Halley's comet. He was a supporter of Newton.
Mathematical Profile (Excerpt):
- There is some confusion over both the date and year of Halley's birth.
- The confusion over the year is less easy to decide, but we give 1656 which Halley himself claimed as the year of his birth.
- Halley made important observations at Oxford, including an occultation of Mars by the Moon on 11 June 1676, which he published in the Philosophical Transactions of the Royal Society.
- The most likely explanation is that with the opening of the Royal Observatory at Greenwich in 1675, Flamsteed undertook the task of mapping the northern hemisphere stars and Halley decided to complement this programme with undertaking a similar task for the southern hemisphere.
- The weather in St Helena proved less good for astronomical observations than Halley had hoped, but despite this his eighteen month spell on the island resulted in his cataloguing 341 southern hemisphere stars and discovered a star cluster in Centaurus.
- Halley returned to England in 1678 and published his catalogue of southern hemisphere stars.
- In 1679 the Royal Society sent Halley to Danzig to arbitrate in a dispute between Hooke and Hevelius.
- The fame and recognition which Halley achieved so quickly did nothing to endear him to Flamsteed who, despite his praise for Halley in his student days, soon turned against him.
- Having the Astronomer Royal as an enemy is not the best recommendation for a young astronomer, even one as famous as Halley, who would soon pay the price.
- Halley did not seek a teaching post at this stage, preferring the freedom to travel and undertake research without commitments.
- Halley observed a comet while near Calais and travelled to Paris where, together with Cassini, he made further observations in an attempt to determine its orbit.
- Much of 1681 Halley spent in Italy.
- Wren, Hooke and Halley then discussed whether it could be shown that the inverse square law implies elliptical orbits for the planets, but failed to come up with a proof.
- but for Halley the Principia would not have existed.
- By now Halley was certainly not a rich man and although in the end his financial outlay which allowed the Principia to be published was reimbursed from the sales, he now sought an academic post.
- Halley's close association with Newton lowered him still further in Flamsteed's eyes.
- Flamsteed was quite right in believing that Halley's view of Christianity was at odds with the standard view of that time which required a literal belief in the Bible.
- Newton also complained to Halley about the fact that Halley doubted the scientific correctness of the biblical story of the creation.
- Despite Halley vigorously claiming that his beliefs were conventional, David Gregory was appointed to the chair.
- The lack of an academic post did not hold Halley back in his scientific work.
- In 1686 Halley published a map of the world showing the prevailing winds over the oceans.
- From around 1695 Halley made a careful study of the orbits of comets.
- Newton favoured comets having parabolic orbits, but Halley believed that elliptical orbits might exist.
- Using his theory of cometary orbits he calculated that the comet of 1682 (now called Halley's comet) was periodic and was the same object as the comet of 1531, and 1607.
- It was not an easy calculation for Halley had to take into account the perturbations to the orbit produced by Jupiter.
- Although Halley had been dead for fifteen years by 1758, he achieved lasting fame when the comet was observed on 25 December 1758 (very slightly later than Halley expected).
- Newton became Warden of the Royal Mint in London in 1696 and he used his influence to have Halley appointed as deputy controller of the mint at Chester in the same year.
- After leaving the mint at Chester, Halley was given the command of a warship, the Paramore Pink, by William III.
- After his return in September 1700, Halley published charts of the variation of the compass, giving the first charts with lines of equal declination plotted.
- Back on the Paramore Pink in 1701, Halley investigated the tides and coasts of southern England.
- Halley was appointed Savilian professor of geometry at Oxford in 1704 following the death of Wallis.
- Halley's inaugural lecture proved a great success.
- In 1710, using Ptolemy's catalogue, Halley deduced that the stars must have small motions of their own and he believed that he was able to detect this proper motion in three stars.
- Halley played an active role in the events and controversies of his time.
- Halley did much to calm disputes, but also seemed to go out of his way to make his dispute with Flamsteed worse.
- At the Greenwich Royal Observatory Halley used the first transit instrument and devised a method for determining longitude at sea by means of lunar observations.
- However, Halley has been criticised for his work as Astronomer Royal.
- It has also been claimed that Halley's observations were carelessly carried out.
- He lists in that article Halley's achievements as Astronomer Royal.
- Halley's other activities included studying archaeology, geophysics, the history of astronomy, and the solution of polynomial equations.
Born 8 November 1656, Haggerston, Shoreditch (near London), England. Died 14 January 1742, Greenwich (near London), England.
View full biography at MacTutor
Tags relevant for this person:
Analysis, Astronomy, Geography, Origin England, Physics
Thank you to the contributors under CC BY-SA 4.0! 
- Github:
-
- non-Github:
- @J-J-O'Connor
- @E-F-Robertson
References
Adapted from other CC BY-SA 4.0 Sources:
- O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive
