Edmund Halley - Astronomer, Scientist, and Innovator
English astronomer Edmond Halley whose name is given to the comet that he studied extensively was a consummate scientist who made significant contributions not only in astronomy but also in physics, meteorology, geophysics, and mathematics. Edmond Halley’s paper, “A Synopsis of the Astronomy of Comets,” which was published in 1705, is considered as his major contribution to astronomy.
Until his death in January 14, 1743 at the age of 87, Halley was a tireless observer and disciple of science. He was a universal philosopher whose insatiable curiosity and thirst for knowledge fueled his desire to explain natural phenomenon. Edmond Halley predicted that the comet he wrote about in his scientific paper would return either in the year 1758 or 1759. It did, but he did not live to see his calculations proven right.
Although there are many uncertainties surrounding Edmond Halley’s birth such as the date, it is known that he was born at Haggerston, Shoreditch, London in England. Some sources state that Halley was born in October 29, 1655, while other set his date of birth at November 8, 1656.
Halley was raised in an affluent household in the Anglican religion. His father was a wealthy man who in his lifetime was a merchant of soap and salt, with numerous real estate properties in London. Though immersed in the mercantile industry, Edmond’s father realized early on that his son was a “promising genius” and so he nurtured is curiosity and love for learning. With his wealth, he provided him with books, tutors, as well as instruments and apparatus for the observation of the night sky.
Unfortunately, in 1684, Edmond’s father was murdered. At that time, Edmond had already lost his mother who passed away in 1672. Edmond’s father financially supported his scientific studies until his untimely death, and afterward, Halley had some personal means to continue funding his activities.
In 1682, Edmond was married to Mary Tooke. They raised three children in Islington.
Tutored at home in his boyhood, Edmond Halley then attended St. Paul’s School from 1671 to 1673 and afterwards to Oxford University, Queen's College, from 1673 to 1676 as was the usual practice amongst wealthy Englishmen in those days. Halley showed an aptitude for astronomy and mathematics. When he entered Queen’s College at the age of 17, he brought with him his personal collection of astronomical instruments, procured by his father. Halley mostly delved in mathematics, astronomy, and physics, but Halley was also interested in meteorology, magnetism, and demography. He published is first scientific paper at the age of 20 on his observations of the gas planets Saturn and Jupiter.
In his undergraduate studies at Oxford, while under the wings of Astronomer Royal John Flamsteed, Halley made important observations on sunspots and an occultation of the red planet, Mars by Earth’s moon. While an undergraduate student, Halley published in the Philosophical Transactions on the topic of theoretical astronomy. While Halley worked as Flamsteed’s assistant at the Greenwich Observatory, he was also tasked to assign Flamsteed numbers to the stars.
At the age of 22, upon receiving his M.A. Degree at Oxford, Edmond Halley was elected to the Royal Society as Fellow. Because of his scientific achievements, he was also accepted as a member of the Académie Royal des Sciences in Paris.
Contributions to Science
Edmond Halley is the founder of the science of geophysics and he published key papers on tides, the sources of fountains and springs, and trade winds. He also developed a general theory of magnetism and made experiments in order to determine the laws that govern the Earth’s magnetic poles. His interest in earth science extends to meteorology, specifically the relationship of weather and barometric pressure. Historical geology was another topic that piqued Halley’s interest.
Edmond Halley also published papers in pure mathematics. He also worked on papers on Apollonius and other ancient geometricians. The translation of the conics of Apollonius was completed in collaboration with David Gregory. Halley was also a pioneer of social statistics. Another area of science that he thought worth unraveling was optics. Halley also involved himself in the study of navigation.
Halley’s body of work also involves contributions to cartography, navigation instruments, and military engineering aside from the methods that he developed to improve his own astronomical calculations. For instance, he published a paper in 1731 about a more accurate means of calculating longitude determination using lunar positions. He also devised a means of determining longitude using magnetic declinations, which had important applications in cartography at that time.
Halley’s interests in instrumentation also included the realms of cartography and navigation. In his long career as a scientist, Edmond Halley improved the backstaff as a tool for measuring the sun’s height, helped John Harrison in the invention of the first longcaseclock in 1713, and he also developed a diving bell for undersea exploration in 1691. Halley also came up with a working model of a magnetic compass and presented the rudimentary device to the members of the Royal Society in London.
Halley’s diving bell
Edmond Halley contributed much toward undersea explorations by the plans that he prepared for a diving bell that could withstand long hours of submersion. He put the plans forward for the first time in 1691 and the results of the subsequent demonstration led to further improvements. The device that he designed provided atmosphere to the diver via weighted barrels of air, which were sent down into the depths. Halley himself, joined by five people demonstrated the use of the diving bell at the River Thames under 18 metres (60 feet) of water. The bell was quite heavy, but the demonstration showed that it could provide ample air to the diver for about an hour and a half. The bell that Halley developed did not become a staple equipment for use in salvage work underwater because of its weight but Halley’s diving bell played an important role in the evolution of diving equipment.
Halley’s association with Sir Isaac Newton
One of the lines of scientific inquiry that Edmond Halley’s was very much interested in was gravity. He was one of the scientists in those days that were studying planetary motion with the intention of providing a mechanical explanation for observed phenomena. Working with Robert Hooke, an accomplished microscopist, Halley failed to arrive at a suitable theory and deduce an orbit matching planetary motions as observed from Earth. The explanation came from Sir Isaac Newton, who proposed an elliptical orbit, which he expounded in detail in his seminal work, “Philosophiae Naturalis Principia Mathematica,” which was published in 1687. Edmond Halley not only persuaded Newton to publish, but he was also the one who recognized the importance of Newton’s work as soon as he saw the calculations. Halley also contributed financially to the publication of Newton’s most important work on celestial mechanics.
In 1705, his work “A Synopsis of the Astronomy of Comets” was published and it was unlike any other research study on the topic. In the paper, Halley described in detail the parabolic orbits of 24 comets. The data came from observations chronicled from 1337 to 1698. Edmond Halley presented the theory that the three comets observed in 1531, in 1607, and in 1682 were similar in a number of parameters that they must be the same object. Halley was the first scientist to make accurate calculations of the comet’s trajectory and periodicity. Because of Halley’s keen scientific mind, mathematical prowess, and excellent observational skills, he was the first to ascertain that the comet that has been documented since 240 BC by ancient astronomers is a comet that “returns” and follows a specific orbit that takes it through the inner solar system.
Halley also made an important discovery about the orbits of comets. He found out that comets travel in a squashed circle or elliptical orbit instead of parabolic orbits. The former allows them to return, to be seen again after a period of time had elapsed, while the latter entails that a comet passes through only once. He plotted the trajectory with care and produced an accurate prediction.
Based on Halley’s calculations, the comet would return in 75 years. It did, and Halley was proven right. In recognition of his work, the comet was named after him.
Halley’s Comet was last seen from Earth in 1986. Its next perihelion is predicted to occur in July 28, 2061. This comet is quite famous because it holds the designation as the one and only short period comet that can be seen without the aid of a telescope. It is the only periodic naked-eye comet known to man. Halley’s Comet is also the only comet that might be seen by a person twice in his or her lifetime.
Other important contributions to astronomy
The orbital path and trajectory of Halley’s Comet is not the only contribution of Edmond Halley to the disciple that took up much of his time. Halley also worked on the “Catalogus Stellarum Australium” or a catalogue of the southern skies, in 1678 to complement the work of his then mentor John Flamsteed on the northern hemisphere. In order to complete this research, Halley sailed to the South Atlantic to the island of St. Helena in 1676, leaving his studies behind. While on the island, he catalogued 341 individual stars and discovered Centaurus, the star cluster, using a sextant with telescopic sights. The publication of his authoritative star catalogue cemented his reputation as a serious astronomer because it was the first catalogue of its kind to present locations of southern stars as determined by a telescope. During his studies of the southern hemisphere, Halley also made observations that contributed to the understanding of the atmosphere and the oceans.
Halley as other important contributions to astronomy such as the secular acceleration of the moon, a method of measuring the Astronomical Unit (AU) using the transit of Venus, and a method of establishing stellar motion.
Occupations and positions held by Edmond Halley
In order to support his scientific inquiry as well as his wife and children, Edmond Halley assumed various salaried positions through the years. He served as the assistant of the secretaries of the Royal Society from 1685 to 1696. His next job, which he held from 1696 to 1698 was deputy controller at the Chester Mint, in which Sir Isaac Newton acted as his patron. For the scientific expedition on navigation, which he led from 1698 to 1701, Halley commanded the vessel Paramore as Naval Captain. He settled into a long-term teaching job as Savilian Professor of Geometry at Oxford from the year 1704 to 1743. Before starting out on his job as professor, Halley served for two years on a mission at an Adriatic naval base to improve its fortifications. While teaching geometry, Halley served as Astronomer Royal from 1720 to 1743. He continued with is naval pursuits as captain on half pay from 1729 to 1743.
Edmond Halley’s legacy
Every student learns about Halley’s Comet during science class, one of the most wonderful things to behold in the sky. There is no argument that the comet is the most celebrated of its kind on Earth, and through the centuries, its arrival is greeted with much anticipation not just by the scientific community but also by regular folk. The comet’s path around the sun takes it close enough to be seen from the Earth, with an orbital period of roughly 75 years. Edmond Halley has been immortalized when his name was given to this heavenly body, and deservedly so.
In recognition of his contributions not only to astronomy, but also to the other fields of study that he delved into with devotion during his lifetime, Halley’s name is also associated with a lunar crater and a crater on the planet Mars. A 680 metre high geological formation in Saint Helena known as Halley’s Mount was christened with his name. The Halley Research Station in Antarctica was named after him as well.
Asimov, Isaac. Asimov's Biographical Encyclopedia of Science and Technology. 2nd Edition. Doubleday & Company, Inc. 1982.