Instruct: Given a question, retrieve relevant documents that can help answer the question.
Query: Who discovered Halley's Comet?
Halley's returns to the inner Solar System have been observed and recorded by astronomers since at least 240 BC. Clear records of the comet's appearances were made by Chinese, Babylonian, and medieval European chroniclers, but were not recognized as reappearances of the same object at the time. The comet's periodicity was first determined in 1705 by English astronomer Edmond Halley, after whom it is now named.
List of Halley-type comets Halley's Comet in fiction
He also developed a method of eliminating systematic errors in positioning brighter comets that resulted in a more accurate prediction of the Halley's Comet. A recalculation of the path of Halley's comet to 2317 BC confirmed that the Greeks had already seen the comet on 466 B.C.
He discovered seven minor planets including 3683 Baumann, 4378 Voigt (named after Hans-Heinrich Voigt), 9938 Kretlow and 4349 Tibúrcio at ESO's La Silla Observatory in northern Chile.
Hale–Bopp's orbital position was calculated as 7.2 astronomical units (AU) from the Sun, placing it between Jupiter and Saturn and by far the greatest distance from Earth at which a comet had been discovered by amateurs. Most comets at this distance are extremely faint, and show no discernible activity, but Hale–Bopp already had an observable coma. An image taken at the Anglo-Australian Telescope in 1993 was found to show the then-unnoticed comet some 13 AU from the Sun, a distance at which most comets are essentially unobservable. (Halley's Comet was more than 100 times fainter at the same distance from the Sun.) Analysis indicated later that its comet nucleus was 60±20 kilometres in diameter, approximately six times the size of Halley.
Ultimately, it was Newton's friend, editor and publisher, Edmond Halley, who, in his 1705 Synopsis of the Astronomy of Comets, used Newton's new laws to calculate the gravitational effects of Jupiter and Saturn on cometary orbits.[22] Having compiled a list of 24 comet observations, he calculated that the orbital elements of a second comet that had appeared in 1682 were nearly the same as those of two comets that had appeared in 1531 (observed by Petrus Apianus) and 1607 (observed by Johannes Kepler).[22][23] Halley thus concluded that all three comets were, in fact, the same object returning about every 76 years, a period that has since been found to vary between 74–79 years. After a rough estimate of the perturbations the comet would sustain from the gravitational attraction of the planets, he predicted its return for 1758.[24] While he had personally observed the comet around perihelion in September 1682,[25] Halley died in 1742 before he could observe its predicted return.[26]
The orbits of the Halley-type comets suggest that they were originally long-period comets whose orbits were perturbed by the gravity of the giant planets and directed into the inner Solar System.[40] If Halley was once a long-period comet, it is likely to have originated in the Oort cloud,[41] a sphere of cometary bodies that has an inner edge of 20,000–50,000 AU. Conversely the Jupiter-family comets are generally believed to originate in the Kuiper belt,[41] a flat disc of icy debris between 30 AU (Neptune's orbit) and 50 AU from the Sun (in the scattered disc). Another point of origin for the Halley-type comets was proposed in 2008, when a trans-Neptunian object with a retrograde orbit similar to Halley's was discovered, 2008 KV42, whose orbit takes it from just outside that of Uranus to twice the distance of Pluto. It may be a member of a new population of small Solar System bodies that serves as the source of Halley-type comets.[43]
As its official designation implies, Encke's Comet was the first periodic comet discovered after Halley's Comet (designated 1P/Halley). It was independently observed by several astronomers, the second being Caroline Herschel in 1795 and the third Jean-Louis Pons in 1818. Its orbit was calculated by Johann Franz Encke, who through laborious calculations was able to link observations of comets in 1786 (designated 2P/1786 B1), 1795 (2P/1795 V1), 1805 (2P/1805 U1) and 1818 (2P/1818 W1) to the same object. In 1819 he published his conclusions in the journal "Correspondance astronomique", and predicted correctly its return in 1822 (2P/1822 L1). It was recovered by Carl Ludwig Christian Rümker at Parramatta Observatory on 2 June 1822.
Halley's Comet or Comet Halley, officially designated 1P/Halley,[1] is a short-period comet visible from Earth every 75–76 years.[1][10][11][12] Halley is the only known short-period comet that is regularly visible to the naked eye from Earth, and the only naked-eye comet that might appear twice in a human lifetime.[13] Halley last appeared in the inner parts of the Solar System in 1986 and will next appear in mid-2061.[14]
The names given to comets have followed several different conventions over the past two centuries. Before any systematic naming convention was adopted, comets were named in a variety of ways. The first one to be named was "Halley's Comet" (now officially known as Comet Halley), named after Edmond Halley, who had calculated its orbit. Similarly, the second known periodic comet, Comet Encke (formally designated 2P/Encke), was named after the astronomer, Johann Franz Encke, who had calculated its orbit rather than the original discoverer of the comet, Pierre Méchain. Other comets that bore the possessive include "Biela's Comet" (3D/Biela) and "Miss Herschel's Comet" (35P/Herschel–Rigollet, or Comet Herschel–Rigollet). Most bright (non-periodic) comets were referred to as 'The Great Comet Of...' the year in which they appeared.
Besides minor planets, he has also discovered 3 comets. The parabolic comet C/1944 H1 observed in 1944 and 1945, as well as the two short period comets, 40P/Vaisala 1, a Jupiter-family comet, and C/1942 EA, a Halley-type and near-Earth comet. Together with Liisi Oterma he co-discovered the Jupiter-family comet 139P/Väisälä-Oterma, which was first classified as asteroid and received the provisional designation "1939 TN".
Halley was the first comet to be recognized as periodic. Until the Renaissance, the philosophical consensus on the nature of comets, promoted by Aristotle, was that they were disturbances in Earth's atmosphere. This idea was disproved in 1577 by Tycho Brahe, who used parallax measurements to show that comets must lie beyond the Moon. Many were still unconvinced that comets orbited the Sun, and assumed instead that they must follow straight paths through the Solar System.[20]
The song is in praise of the famous Halley comet and the band's joy with it, with the objective to give a good new, Halley comet could be seen in Earth. This comet only can be seen from Earth every 76 years, and could be seen in 1986, named after the astronomer Edmond Halley.
Halley at first agreed with the longtime consensus that each comet was a different entity making a single visit to the solar system. In 1705, he applied Newton's method to 23 cometary apparitions that had occurred between 1337 and 1698. Halley noted that three of these, the comets of 1531, 1607, and 1682, had very similar orbital elements, and he was further able to account for the slight differences in their orbits in terms of gravitational perturbation by Jupiter and Saturn. Confident that these three apparitions had been three appearances of the same comet, he predicted that it would appear again in 1758–9. (Earlier, Robert Hooke had identified the comet of 1664 with that of 1618, while Giovanni Domenico Cassini had suspected the identity of the comets of 1577, 1665, and 1680. Both were incorrect.) Halley's predicted return date was later refined by a team of three French mathematicians: Alexis Clairaut, Joseph Lalande, and Nicole-Reine Lepaute, who predicted the date of the comet's 1759 perihelion to within one month's accuracy. Halley died before the comet's return; when it returned as predicted, it became known as Halley's Comet (with the latter-day designation of 1P/Halley). The comet next appears in 2061.
In November 1703, Halley was appointed Savilian Professor of Geometry at the University of Oxford, his theological enemies, John Tillotson and Bishop Stillingfleet having died, and received an honorary degree of doctor of laws in 1710. In 1705, applying historical astronomy methods, he published "Synopsis Astronomia Cometicae", which stated his belief that the comet sightings of 1456, 1531, 1607, and 1682 were of the same comet, which he predicted would return in 1758. Halley did not live to witness the comet's return, but when it did, the comet became generally known as Halley's Comet.
Halley married Mary Tooke in 1682 and settled in Islington. The couple had three children.There are three pronunciations of the surname "Halley". The most common, both in Great Britain and in the United States, is (rhymes with "valley"). This is the personal pronunciation used by most Halleys living in London today.
The alternative 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. Colin Ronan, one of Halley's biographers, preferred . Contemporary accounts spell his name "Hailey, Hayley, Haley, Haly, Halley, Hawley" and "Hawly", and presumably pronunciations varied similarly.
After Edmund Halley demonstrated that the comets of 1531, 1607, and 1682 were the same body and successfully predicted its return in 1759 by calculating its orbit, that comet became known as Halley's Comet. Similarly, the second and third known periodic comets, Encke's Comet and Biela's Comet, were named after the astronomers who calculated their orbits rather than their original discoverers. Later, periodic comets were usually named after their discoverers, but comets that had appeared only once continued to be referred to by the year of their appearance.
It was Wilhelm von Biela, an army officer serving at the fortress town of Josefstadt, who observed the comet during its 1826 perihelion approach (on February 27) and calculated its orbit, discovering it to be periodic with a period of 6.6 years. At the time it was only the third comet known to be periodic, after comets Halley and Encke. The comet was named after Biela, although there was initially some controversy due to a later but independent discovery by Jean-Félix Adolphe Gambart, who also provided the first mathematical proof linking the 1826 and 1805 comets (letters from Biela and Gambart were published in the same issue of the "Astronomische Nachrichten"). A third claim was made by Thomas Clausen, who had independently linked the comets.
About 80% of the Halley's Comet nucleus is water ice, and frozen carbon monoxide (CO) makes up another 15%. Much of the remainder is frozen carbon dioxide, methane, and ammonia. Scientists think that other comets are chemically similar to Halley's Comet. The nucleus of Halley's Comet is also an extremely dark black. Scientists think that the surface of the comet, and perhaps most other comets, is covered with a black crust of dust and rock that covers most of the ice. These comets release gas only when holes in this crust rotate toward the Sun, exposing the interior ice to the warming sunlight.
The following is a list of Halley-type comets (HTCs), which are periodic comets with an orbital period between 20 and 200 years, often appearing only once or twice within one's lifetime. The majority come from between the orbits of Saturn and Neptune; Due to the nature of their orbits, their orbits can be perturbed by the giant planets and sent into orbits too far from the Sun to outgas, and vice versa. Minor planets in comet-like orbits similar to HTCs that never come close enough to the Sun to outgas are called centaurs. HTCs are named after the first discovered member, and the first discovered periodic comet, Halley's Comet, which orbits the Sun in about 75 years, and passing as far as the orbit of Neptune.
After Edmond Halley demonstrated that the comets of 1531, 1607, and 1682 were the same body and successfully predicted its return in 1759, that comet became known as Halley's Comet. Similarly, the second and third known periodic comets, Encke's Comet and Biela's Comet, were named after the astronomers who calculated their orbits rather than their original discoverers. Later, periodic comets were usually named after their discoverers, but comets that had appeared only once continued to be referred to by the year of their apparition.
The game takes place in an alternate history in 1906 where the British Empire rules all of Earth and several extrasolar colony worlds, powered by technology brought to the planet by Halley's Comet in 1835. An unknown substance known as Halley's Core was found throughout the world, and certain individuals who came in contact with it and gained superhuman abilities became known as "Halley's Chosen." The first of these was a scientist named Dr. Hebble Gate, who was affected by the comet while in his mother's womb. With his superhuman mind he harnessed the power of Halley's Core and discovered a wide range of scientific breakthroughs, including fusion and nuclear power, genetic engineering, computers, space travel and countless others. With these technologies the British Empire quickly conquered the earth, and Gate is famous as the man responsible. A complete mystery to all, Gate also holds great power over economic, political and military affairs, and is the founder of the Hebble Foundation and the GunValkyrie (GV) Organization, composed of Halley's Chosen throughout the world to prevent the misuse of technology. He suddenly disappears, throwing the world into shock, and has been missing for four years by the time the game begins.
Halley is classified as a periodic or short-period comet; one with an orbit lasting 200 years or less.[40] This contrasts it with long-period comets, whose orbits last for thousands of years. Periodic comets have an average inclination to the ecliptic of only ten degrees, and an orbital period of just 6.5 years, so Halley's orbit is atypical.[30] Most short-period comets (those with orbital periods shorter than 20 years and inclinations of 20–30 degrees or less) are called Jupiter-family comets. Those resembling Halley, with orbital periods of between 20 and 200 years and inclinations extending from zero to more than 90 degrees, are called Halley-type comets.[40][41] As of 2015, only 75 Halley-type comets have been observed, compared with 511 identified Jupiter-family comets.[42]
Among the comets with short enough periods to have been observed several times in the historical record, Halley's Comet is unique in that it is consistently bright enough to be visible to the naked eye while passing through the inner Solar System. Since the confirmation of the periodicity of Halley's Comet, other [periodic comet]]s have been discovered through the use of the telescope. The second comet found to have a periodic orbit was Encke's Comet (with the official designation of 2P/Encke). During the period 1819–21 the German mathematician and physicist Johann Franz Encke computed the orbits for a series of comets that had been observed in 1786, 1795, 1805, and 1818, and he concluded that they were same comet, and successfully predicted its return in 1822. By 1900, seventeen comets had been observed through more than one passage through their perihelions, and then recognized as being periodic comets. , 305 comets have achieved this distinction, although several of these have disintegrated or been lost.
Comet Crommelin, also known as Comet Pons-Coggia-Winnecke-Forbes, is a periodic comet with an orbital period of almost 28 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years). It is named after the British astronomer Andrew C. D. Crommelin who calculated its orbit in 1930. It is one of only four comets not named after their discoverer(s), the other three being Comets Halley, Encke, and Lexell.
The first near-Earth objects to be observed by humans were comets. Their extraterrestrial nature was recognised and confirmed only after Tycho Brahe tried to measure the distance of a comet through its parallax in 1577; and the periodicity of some comets was recognised in 1705, when Edmond Halley first published his orbit calculations for the returning object now known as Halley's Comet. The 1758–1759 return of Halley's Comet was the first comet appearance predicted in advance.