When was Halley's Comet first discovered?
Observational history of comets
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.
Sungrazing comet
One of the first comets to have its orbit computed was the sungrazing comet (and Great Comet) of 1680, now designated C/1680 V1. It was observed by Isaac Newton and he published the orbit results in 1687. Later, in 1699, Jacques Cassini proposed that comets could have relatively short orbital periods and that C/1680 V1 was the same as a comet observed by Tycho Brahe in 1577, but in 1705 Edmond Halley determined that the difference between the perihelion distances of the two comets was too great for them to be the same object. However, this marked the first time that it was hypothesized that Great Comets were related or perhaps the same comet. Later, Johann Franz Encke computed the orbit of C/1680 V1 and found a period of approximately 9000 years, leading him to conclude that Cassini's theory of short period sungrazers was flawed. C/1680 V1 had the smallest measured perihelion distance until the observation in 1826 of comet C/1826 U1.
Historical comet observations in China
Ancient Chinese records of comet observations are the most extensive historical records in existence. They are far more complete than European observations. The earliest confirmed Chinese comet observation is from 613 BC, but there is also a possible sighting of Halley's Comet in 1059 BC. However, this may not be an actual sighting, but the result of later back calculation.
Historical comet observations in China
In 1843 engineer and sinologist Édouard Biot translated Chinese records of comets. Astronomer John Russell Hind observed that past apparitions of Halley back to 12 BC in most cases could be matched to these Chinese records.
Friedrich Bessel
Bessel came to the attention of a major figure of German astronomy at the time, Heinrich Wilhelm Olbers, by producing a refinement on the orbital calculations for Halley's Comet in 1804, using old observation data taken from Thomas Harriot and Nathaniel Torporley in 1607.
Halley's Comet
The next predicted perihelion of Halley's Comet is 28 July 2061, when it is expected to be better positioned for observation than during the 1985–1986 apparition, as it will be on the same side of the Sun as Earth. It is expected to have an apparent magnitude of −0.3, compared with only +2.1 for the 1986 apparition. It has been calculated that on 9 September 2060, Halley will pass within of Jupiter, and then on 20 August 2061 will pass within of Venus. In 2134, Halley is expected to pass within of Earth. Its apparent magnitude is expected to be −2.0.
Vahe Gurzadyan
He identified the Halley's comet depicted on ancient coins of Armenian king Tigranes the Great, I c.BC. as the earliest known image of that comet He revealed the observation of supernova SN 1054 (progenitor of Crab nebula) in Armenian medieval chronicle of Hetum (Hayton of Corycus) and Cronaca Rampona.
Rosetta (spacecraft)
During the 1986 approach of Halley's Comet, international space probes were sent to explore the comet, most prominent among them being ESA's "Giotto". After the probes returned valuable scientific information, it became obvious that follow-ons were needed that would shed more light on cometary composition and answer new questions.
Historical comet observations in China
A computer calculation of the past orbits of Halley using numerical integration could not continue past 837 AD because a very close approach to Earth made calculation of orbits prior to that too inaccurate. The researchers had started with accurate European measurements from 1759, 1682 and 1607 AD and calculated backwards. However, no accurate European records exist for 837 AD so the researchers looked to Chinese records. From these they obtained a good estimate of the perihelion of Halley for that year. They used that, together with perihelions found from Chinese data for 374 and 141 AD, to provide constraints for their calculation. They were finally able to calculate the orbits of Halley back to 1404 BC.
Ralph Steadman
In 1985, Steadman designed a set of four British postage stamps to commemorate the appearance that year of Halley's Comet.
Pope Callixtus III
According to one story that first appeared in a 1475 posthumous biography and was subsequently embellished and popularized by Pierre-Simon Laplace, Callixtus III excommunicated the 1456 appearance of Halley's Comet, believing it to be an ill omen for the Christian defenders of Belgrade from the besieging armies of the Ottoman Empire. No known primary source supports the authenticity of this account. The 29 June 1456 papal bull of Callixtus III calling for a public prayer for the success of the crusade makes no mention of the comet. By 6 August, when the Turkish siege was broken, the comet had not been visible in either Europe or Turkey for several weeks.
122P/de Vico
122P/de Vico (provisional designation: 1846 D1) is a periodic comet with an orbital period of 74 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years). It was discovered by Francesco de Vico in Rome on February 20, 1846.
Comet Swift–Tuttle
Comet Swift–Tuttle (formally designated 109P/Swift–Tuttle) is a periodic comet with a current (osculating) orbital period of 133 years. It fits the classical definition of a Halley-type comet with a period between 20 and 200 years. It was independently discovered by Lewis Swift on July 16, 1862 and by Horace Parnell Tuttle on July 19, 1862. It has a well determined orbit and has a comet nucleus 26 km in diameter.
List of Halley-type comets
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.
Halley's Comet
Researchers in 1981 attempting to calculate the past orbits of Halley by numerical integration starting from accurate observations in the seventeenth and eighteenth centuries could not produce accurate results further back than 837 due to a close approach to Earth in that year. It was necessary to use ancient Chinese comet observations to constrain their calculations.
Comet nucleus
During a flyby in September 2001, the Deep Space 1 spacecraft observed the nucleus of Comet Borrelly and found it to be about half the size (8×4×4 km) of the nucleus of Halley's Comet. Borrelly's nucleus was also potato-shaped and had a dark black surface. Like Halley's Comet, Comet Borrelly only released gas from small areas where holes in the crust exposed the ice to sunlight.
The nucleus of comet Hale–Bopp was estimated to be 60 ± 20 km in diameter. Hale-Bopp appeared bright to the unaided eye because its unusually large nucleus gave off a great deal of dust and gas.
23P/Brorsen–Metcalf
23P/Brorsen–Metcalf is a periodic comet with an orbital period of 70 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years). It was first discovered by Theodor Brorsen at the Altona Observatory on July 20, 1847, and again by Kaspar Schweizer (Moscow) on August 11, 1847. It was predicted that it would reappear between 1919 and 1922.
Comet Holmes
The 1899 and 1906 appearances were observed, but the comet was lost (see Lost comet) after 1906 until it was recovered on July 16, 1964, by Elizabeth Roemer (US Naval Observatory Flagstaff Station, Arizona, United States). Aided by the computer predictions of Brian G. Marsden, the comet has been observed on every subsequent return.
Halley's Comet
In 1066, the comet was seen in England and thought to be an omen: later that year Harold II of England died at the Battle of Hastings; it was a bad omen for Harold, but a good omen for the man who defeated him, William the Conqueror. The comet is represented on the Bayeux Tapestry and described in the tituli as a star. Surviving accounts from the period describe it as appearing to be four times the size of Venus and shining with a light equal to a quarter of that of the Moon. Halley came within 0.10 AU of Earth at that time.
Star of Bethlehem
Other writers suggest that the star was a comet. Halley's Comet was visible in 12 BC and another object, possibly a comet or nova, was seen by Chinese and Korean stargazers in about 5 BC. This object was observed for over seventy days, possibly with no movement recorded. Ancient writers described comets as "hanging over" specific cities, just as the Star of Bethlehem was said to have "stood over" the "place" where Jesus was (the town of Bethlehem). However, this is generally thought unlikely as in ancient times comets were generally seen as bad omens. The comet explanation has been recently promoted by Colin Nicholl. His theory involves a hypothetical comet which could have appeared in 6 BC.
Halley's Comet
The 374 AD and 607 approaches each came within 0.09 AU of Earth. The 684 AD apparition was recorded in Europe in one of the sources used by the compiler of the 1493 Nuremberg Chronicles; it is the oldest-known picture of a comet. Chinese records also report it as the "broom star". The 451 AD apparition was said to herald the defeat of Attila the Hun at the Battle of Chalons.
In 837, Halley's Comet may have passed as close as 0.03 AU (3.2 million miles; 5.1 million kilometres) from Earth, by far its closest approach. Its tail may have stretched 60 degrees across the sky. It was recorded by astronomers in China, Japan, Germany, the Byzantine Empire, and the Middle East. In 912, Halley is recorded in the "Annals of Ulster", which state "A dark and rainy year. A comet appeared."
Crab Nebula
The Crab Nebula was first identified in 1731 by John Bevis. The nebula was independently rediscovered in 1758 by Charles Messier as he was observing a bright comet. Messier catalogued it as the first entry in his catalogue of comet-like objects; in 1757, Alexis Clairaut reexamined the calculations of Edmund Halley and predicted the return of Halley's Comet in late 1758. The exact time of the comet's return required the consideration of perturbations to its orbit caused by planets in the Solar System such as Jupiter, which Clairaut and his two colleagues Jérôme Lalande and Nicole-Reine Lepaute carried out more precisely than Halley, finding that the comet should appear in the constellation of Taurus. It is in searching in vain for the comet that Charles Messier found the Crab nebula, which he at first thought to be Halley's comet. After some observation, noticing that the object that he was observing was not moving across the sky, Messier concluded that the object was not a comet. Messier then realised the usefulness of compiling a catalogue of celestial objects of a cloudy nature, but fixed in the sky, to avoid incorrectly cataloguing them as comets.
Science in the Age of Enlightenment
Building on the body of work forwarded by Copernicus, Kepler and Newton, 18th-century astronomers refined telescopes, produced star catalogues, and worked towards explaining the motions of heavenly bodies and the consequences of universal gravitation. Among the prominent astronomers of the age was Edmund Halley. In 1705, Halley correctly linked historical descriptions of particularly bright comets to the reappearance of just one, which would later be named Halley’s Comet, based on his computation of the orbits of comets. Halley also changed the theory of the Newtonian universe, which described the fixed stars. When he compared the ancient positions of stars to their contemporary positions, he found that they had shifted. James Bradley, while attempting to document stellar parallax, realized that the unexplained motion of stars he had early observed with Samuel Molyneux was caused by the aberration of light. The discovery was proof of a heliocentric model of the universe, since it is the revolution of the earth around the sun that causes an apparent motion in the observed position of a star. The discovery also led Bradley to a fairly close estimate to the speed of light.
Comet Hale–Bopp
Hale had spent many hundreds of hours searching for comets without success, and was tracking known comets from his driveway in New Mexico when he chanced upon Hale–Bopp just after midnight. The comet had an apparent magnitude of 10.5 and lay near the globular cluster M70 in the constellation of Sagittarius. Hale first established that there was no other deep-sky object near M70, and then consulted a directory of known comets, finding that none were known to be in this area of the sky. Once he had established that the object was moving relative to the background stars, he emailed the Central Bureau for Astronomical Telegrams, the clearing house for astronomical discoveries.
Space Place at Carter Observatory
After Crossley’s death in 1905, the telescope was purchased by Reverend Dr David Kennedy and shipped to New Zealand, where it was installed at the Meeanee Observatory at the Marist Seminary near Napier. Kennedy used the telescope to take photographs of Halley’s Comet during its 1910 approach.
Halley's Comet
Halley's orbital period has varied between 74–79 years since 240 BC. Its orbit around the Sun is highly elliptical, with an orbital eccentricity of 0.967 (with 0 being a circle and 1 being a parabolic trajectory). The perihelion, the point in the comet's orbit when it is nearest the Sun, is just 0.6 AU. This is between the orbits of Mercury and Venus. Its aphelion, or farthest distance from the Sun, is 35 AU (roughly the distance of Pluto). Unusual for an object in the Solar System, Halley's orbit is retrograde; it orbits the Sun in the opposite direction to the planets, or, clockwise from above the Sun's north pole. The orbit is inclined by 18° to the ecliptic, with much of it lying south of the ecliptic. (Because it is retrograde, the true inclination is 162°.) Due to the retrograde orbit, it has one of the highest velocities relative to the Earth of any object in the Solar System. The 1910 passage was at a relative velocity of 70.56 km/s (157,838 mph or 254,016 km/h). Because its orbit comes close to Earth's in two places, Halley is associated with two meteor showers: the Eta Aquariids in early May, and the Orionids in late October. Halley is the parent body to the Orionids. Observations conducted around the time of Halley's appearance in 1986 suggested that the comet could additionally perturb the Eta Aquariids meteor shower, although it might not be the parent of that shower.
Johann Franz Encke
Following a suggestion by Jean-Louis Pons, who suspected one of the three comets discovered in 1818 to be the same one already discovered by him in 1805, Encke began to calculate the orbital elements of this comet. At this time, all the known comets had an orbital period of seventy years and more, with an aphelion far beyond the orbit of Uranus. The most famous comet of this family was Comet Halley with its period of seventy-six years. So the orbit of the comet discovered by Pons was a sensation, because his orbit was found to have a period of 3.3 years, so that the aphelion had to be within the orbit of Jupiter. Encke predicted its return for 1822, but this return was observable only from the southern hemisphere and was seen by Carl Ludwig Christian Rümker in Australia. The comet was also identified with the one seen by Pierre Méchain in 1786 and by Caroline Herschel in 1795.
Thomas Bopp
Bopp later acknowledged the chance discovery, The following morning at 8:25am the office of Brian Marsden, director of the Central Bureau for Astronomical Telegrams, called him back to confirm the sighting was indeed a comet. The comet was given the formal name Comet 1995 O1, and three days later its full title C/1995 O1 (Hale–Bopp), designating the first comet found during the second half-month of July 1995. Hale's name precedes Bopp's because his was the first report to arrive. It is uncertain who was the first to discover it, as they both spotted it at around the same time. The following day Hale phoned Bopp to introduce himself with the words, "I think that we have something in common." When they met at a conference two months later, Bopp admitted to the press that Hale "turned out to be a nice guy."
Giotto (spacecraft)
Giotto was a European robotic spacecraft mission from the European Space Agency. The spacecraft flew by and studied Halley's Comet and in doing so became the first spacecraft to make close up observations of a comet. On 13 March 1986, the spacecraft succeeded in approaching Halley's nucleus at a distance of 596 kilometers. It was named after the Early Italian Renaissance painter Giotto di Bondone, who draw free hand perfect circles according to Giorgio Vasari biography. He had observed Halley's Comet in 1301 and was inspired to depict it as the star of Bethlehem in his painting "Adoration of the Magi".
Halley's Comet
Platina's account is not mentioned in official records. In the 18th century, a Frenchman further embellished the story, in anger at the Church, by claiming that the Pope had "excommunicated" the comet, though this story was most likely his own invention.
Historical comet observations in China
Around forty comets have had their orbits calculated based entirely on ancient Chinese records. Of the well known comets, besides Halley, Brian G. Marsden suggested, based on Chinese and other ancient observations, that the Great Comet of 1106 was a previous apparition of Comet Ikeya–Seki.
Comet
In times past, bright comets often inspired panic and hysteria in the general population, being thought of as bad omens. More recently, during the passage of Halley's Comet in 1910, the Earth passed through the comet's tail, and erroneous newspaper reports inspired a fear that cyanogen in the tail might poison millions, whereas the appearance of Comet Hale–Bopp in 1997 triggered the mass suicide of the Heaven's Gate cult.
Naming of comets
The simplest system names comets after the year in which they were observed (e.g. the Great Comet of 1680). Later a convention arose of using the names of people associated with the discovery (e.g. Comet Hale–Bopp) or the first detailed study (e.g. Halley's Comet) of each comet. During the twentieth century, improvements in technology and dedicated searches led to a massive increase in the number of comet discoveries, which led to the creation of a numeric designation scheme. The original scheme assigned codes in the order that comets passed perihelion (e.g. Comet 1970 II). This scheme operated until 1994, when continued increases in the numbers of comets found each year resulted in the creation of a new scheme. This system, which is still in operation, assigns a code based on the type of orbit and the date of discovery (e.g. C/2012 S1).
Space probe
The first dedicated missions to a comet; in this case, to Halley's Comet during its 1985–86 journey through the inner Solar System. It was also the first massive international coordination of space probes on an interplanetary mission, with probes specifically launched by the Soviet (now Russian) Space Agency, European Space Agency, and Japan's ISAS (now integrated with NASDA to JAXA).
Halley's Comet
If, as has been suggested, the reference in the Talmud to "a star which appears once in seventy years that makes the captains of the ships err" (see above) refers to Halley's Comet, it may be a reference to the 66 AD appearance, because this passage is attributed to the Rabbi Yehoshua ben Hananiah. This apparition was the only one to occur during ben Hananiah's lifetime.
Thomas Harriot
Halley's Comet in 1607 turned Harriot's attention towards astronomy. In early 1609 he bought a "Dutch trunke" (telescope), invented in 1608, and his observations were among the first uses of a telescope for astronomy. Harriot is now credited as the first astronomer to draw an astronomical object after viewing it through a telescope: he drew a map of the Moon on 26 July 1609, preceding Galileo by several months. He also observed sunspots in December 1610.
Halley's Comet
American satirist and writer Mark Twain was born on 30 November 1835, exactly two weeks after the comet's perihelion. In his autobiography, published in 1909, he said,
Oort cloud
There are two main varieties of short-period comet: Jupiter-family comets (those with semi-major axes of less than 5 AU) and Halley-family comets. Halley-family comets, named for their prototype, Halley's Comet, are unusual in that although they are short-period comets, it is hypothesized that their ultimate origin lies in the Oort cloud, not in the scattered disc. Based on their orbits, it is suggested they were long-period comets that were captured by the gravity of the giant planets and sent into the inner Solar System. This process may have also created the present orbits of a significant fraction of the Jupiter-family comets, although the majority of such comets are thought to have originated in the scattered disc.
Halley's Comet
Halley is classified as a "periodic" or "short-period comet"; one with an orbit lasting 200 years or less. 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. 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. , only 75 Halley-type comets have been observed, compared with 511 identified Jupiter-family comets.
International Halley Watch
Halley's Comet, named after English astronomer Edmund Halley who first demonstrated its periodicity, returns to the vicinity of the Sun and Earth approximately every 76 years. Since comets are believed to be the most primordial objects in the solar system, their study is of great importance to planetary science. At the time of the 1986 return (technically, "apparition") of the comet, astronomical telescopes and related instrumentation were vastly more sensitive than for any previous apparition. Consequently, the International Halley Watch (IHW) was organized to stimulate, standardize, collect, and archive observations of the comet.
Astronomical naming conventions
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.
Han dynasty
Han Chinese astronomers made star catalogues and detailed records of comets that appeared in the night sky, including recording the 12 BC appearance of the comet now known as Halley's Comet.
Science and technology of the Han dynasty
The Han-era Chinese noted the passage of the same comet seen in Persia for the birth of Mithridates II of Parthia in 135 BCE, the same comet the Romans observed close to the assassination of Julius Caesar in 44 BCE, Halley's comet in 12 BCE, the same comet noted by Roman historian Cassius Dio (c. 155 – c. 229 CE) for 13 CE, and (what is now known to have been) a supernova in AD 185. For various comets discussed in the Han-era history books "Records of the Grand Historian" and "Book of Han", details are given for their position in the sky and direction they were moving, the length of time they were visible, their color, and their size.
William Pearson (astronomer)
Pearson observed Halley's comet on 29 October 1835, and in 1839 he deduced a value for the obliquity of the ecliptic from his own research.
Halley's Comet
Halley is the most active of all the periodic comets, with others, such as Comet Encke and Comet Holmes, being one or two orders of magnitude less active. Its day side (the side facing the Sun) is far more active than the night side. Spacecraft observations showed that the gases ejected from the nucleus were 80% water vapour, 17% carbon monoxide and 3–4% carbon dioxide, with traces of hydrocarbons although more-recent sources give a value of 10% for carbon monoxide and also include traces of methane and ammonia. The dust particles were found to be primarily a mixture of carbon–hydrogen–oxygen–nitrogen (CHON) compounds common in the outer Solar System, and silicates, such as are found in terrestrial rocks. The dust particles decreased in size down to the limits of detection (~0.001 µm). The ratio of deuterium to hydrogen in the water released by Halley was initially thought to be similar to that found in Earth's ocean water, suggesting that Halley-type comets may have delivered water to Earth in the distant past. Subsequent observations showed Halley's deuterium ratio to be far higher than that found in Earth's oceans, making such comets unlikely sources for Earth's water.
Halley's Comet
The comet added to the unrest in China on the eve of the Xinhai Revolution that would end the last dynasty in 1911. As James Hutson, a missionary in Sichuan Province at the time, recorded,
Orionids
Meteor showers first designated "shooting stars" were connected to comets in the 1800s. E.C. Herrick made an observation in 1839 and 1840 about the activity present in the October night skies. A. S. Herschel produced the first documented record that gave accurate forecasts for the next meteor shower. The Orionid meteor shower is produced by the well known Halley's Comet, which was named after the astronomer Edmund Halley and last passed through the inner solar system in 1986 on its 75- to 76-year orbit. When the comet passes through the solar system, the sun sublimates some of the ice, allowing rock particles to break away from the comet. These particles continue on the comet's trajectory and appear as meteors ("falling stars") when they pass through Earth's upper atmosphere. Halley's comet is also responsible for creating the Eta Aquariids, which occur each May.
Naming of comets
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.
Torquetum
Following the conception of the "torquetum", the device had been put through many of the following uses. The astronomer, Peter of Limoges, used this device for his observation of what is known today as Halley's Comet at the turn of the 14th century. In the early 1300s, John of Murs mentions the "torquetum" as his defense "of the reliability of observational astronomy", thus further solidifying its practicality and viability in ancient astronomy. Additionally, Johannes Schoner built a torquetum model for his own personal use in the observation of Halley's Comet in the 1500.
Halley's Comet (video game)
Halley's Comet is an arcade video game created by Pacific Manufacturing Ltd and manufactured by its parent company Taito. Receiving a worldwide release in 1986, Halley's Comet is a vertical scrolling shoot 'em up where the player defends various planets around the solar system from a direct collision with Halley's Comet and the various alien swarms which accompany it.
Johannes Remus Quietanus
In 1607, he observed the passage of a comet, and then wrote a booklet of some fifty pages titled "Gründliche Beschreibung des neuen monstrosischen Sternes, welcher anno Christi 1607 …am hohen Himmel geleichtet", ("Accurate description of the new monstrous star that shone in the sky from July 27 to mid-October in 1607"), where he proposed an astrological interpretation of this ""sign of God"". This was actually Halley's comet that did not yet bear the current name.
Halley's Comet
The apparition of 87 BC was recorded in Babylonian tablets which state that the comet was seen "day beyond day" for a month. This appearance may be recalled in the representation of Tigranes the Great, an Armenian king who is depicted on coins with a crown that features, according to Vahe Gurzadyan and R. Vardanyan, "a star with a curved tail [that] may represent the passage of Halley's Comet in 87 BC." Gurzadyan and Vardanyan argue that "Tigranes could have seen Halley's Comet when it passed closest to the Sun on August 6 in 87 BC" as the comet would have been a "most recordable event"; for ancient Armenians it could have heralded the New Era of the brilliant King of Kings.
Historical comet observations in China
Chinese observations of Halley's Comet are of especial importance to astronomers because of the important place this comet had in their growing understanding of them. The earliest confirmed sighting was in 240 BC (in the "Records of the Grand Historian")—with a continuous record after 164 BC. A comet observed in 467 BC may have been Halley, but there is insufficient information to be sure. The most accurate records of Halley begin in 12 BC.
Comet
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.
Observational history of comets
Since 1985, a total of 8 comets have been visited by spacecrafts. These were the comets Halley, Borrelly, Giacobini–Zinner, Tempel 1, Wild 2, Hartley 2, Grigg–Skjellerup and Churyumov–Gerasimenko, generating a host of new findings. In addition, the spacecraft "Ulysses" unexpectedly traversed the tail of Comet McNaught.
Jan Oort
Oort went on to study comets, which he formulated a number of revolutionary hypotheses. He hypothesized that the Solar System is surrounded by a massive cloud consisting of billions of comets, many of them “long-period” comets that originate in a cloud far beyond the orbits of Neptune and Pluto. This cloud is now known as the Oort Cloud. He also realized that these external comets, from beyond Pluto, can “become trapped into tighter orbits by Jupiter, and become periodic comets, like Halley's comet.” According to one source, “Oort was one of the few people to have seen Comet Halley on two separate apparitions. At the age of 10, he was with his father on the shore at Noordwijk, Netherlands, when he first saw the comet. In 1986, 76 years later, he went up in a plane and was able to see the famous comet once more.”
Halley's Comet Opal
The Halley's Comet Opal is the largest uncut black opal in the world, according to the Guinness Book of World Records. It is so named because it was unearthed in 1986, a year when Halley's Comet could be seen from Earth. It is the third largest gem grade black opal ever recorded, the largest one extant, and the largest specimen ever found in its region. It was found at Lightning Ridge, New South Wales, Australia by the Lunatic Hill Mining Syndicate. It weighs (13.99 ounces) and is about the size of a man's fist. The Halley's Comet Opal is a very fine specimen, with few flaws or blemishes and a large green and orange thick color bar which goes through the opal. Formed about 20 million years ago, it is an example of a nobby, which is a natural lump-shaped opal found only at Lightning Ridge. As of 2006 it was for sale at $1.2 million.
Halley's Comet
Two Space Shuttle missions—the ill-fated STS-51-L (ended by the "Challenger" disaster) and STS-61-E—were scheduled to observe Halley's Comet from low Earth orbit. STS-51-L carried the Shuttle-Pointed Tool for Astronomy (SPARTAN-203) satellite, also called the Halley's Comet Experiment Deployable (HCED). STS-61-E was a "Columbia" mission scheduled for March 1986, carrying the ASTRO-1 platform to study the comet. Due to the suspension of America's manned space program after the "Challenger" explosion, the mission was canceled, and ASTRO-1 would not fly until late 1990 on STS-35.
Aegospotami
According to ancient sources including Pliny the Elder and Aristotle, in 467 BC a large meteorite landed near Aegospotami. It was described as brown in colour and the size of a wagon load; it was a local landmark for more than 500 years. A comet, tentatively identified as Halley's Comet, was reported at the time the meteorite landed. This is possibly the first European record of Halley's comet.
Halley's Comet
Halley may have been recorded as early as 467 BC, but this is uncertain. A comet was recorded in ancient Greece between 468 and 466 BC; its timing, location, duration, and associated meteor shower all suggest it was Halley. According to Pliny the Elder, that same year a meteorite fell in the town of Aegospotami, in Thrace. He described it as brown in colour and the size of a wagon load. Chinese chroniclers also mention a comet in that year.
Historical comet observations in China
The Chinese records are not only the most extensive from ancient times, they are also the most accurate, often to within half a degree of right ascension. Western measurements did not overtake them for accuracy until the fifteenth century: in 1456 AD Paolo Toscanelli tracked the progress of Halley's Comet to within a fraction of a degree.
Comet Hale–Bopp
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.
80P/Peters–Hartley
It was originally discovered by Christian Heinrich Friedrich Peters of Capodimonte Observatory, Naples, Italy. There was insufficient data to accurately compute the orbit, and the comet was lost for well over a hundred years.
Clay tablet
Late Babylonian tablets at the British Museum refer to appearances of Halley's Comet in 164BC and 87BC.
Halley (song)
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.
C/1807 R1
For this comet there were observational data for over six months and thus for a significant part of the cometary orbit Bessel's calculated predictions could be compared to the observations. The great comet of 1807 is the first long-period comet (other than Halley's comet, which was already known to be periodic) for which there is empirical verification that it moves in an elliptical, and not in a parabolic, orbit.
Comet Encke
Comet Encke or Encke's Comet (official designation: 2P/Encke) is a periodic comet that completes an orbit of the Sun once every 3.3 years. (This is the shortest period of a reasonably bright comet; the faint main-belt comet 311P/PANSTARRS has a period of 3.2 years.) Encke was first recorded by Pierre Méchain in 1786, but it was not recognized as a periodic comet until 1819 when its orbit was computed by Johann Franz Encke; like Halley's Comet, it is unusual in being named after the calculator of its orbit rather than its discoverer. Like most comets, it has a very low albedo, reflecting only 4.6% of the light it receives. The diameter of the nucleus of Encke's Comet is 4.8 km.
Timeline of astronomy
The returning Halley's comet is met by a fleet of five probes from Russia, Japan, and Europe. The most ambitious is the European Space Agency's Giotto spacecraft, which flies through the comet's coma and photographs the nucleus.
Edmond Halley
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.
Observational history of comets
Ancient Chinese records of comet apparitions have been particularly useful to modern astronomers. They are accurate, extensive, and consistent over three millennia. The past orbits of many comets have been calculated entirely from these records and most notably they were used in connection with Halley's comet.
Geminiano Montanari
On 21 March 1676 Montanari reported a sighting of a comet to Edmund Halley.
Comet Hale–Bopp
Hale–Bopp was discovered on July 23, 1995, separately by Alan Hale and Thomas Bopp prior to it becoming naked-eye visible on Earth. Although predicting the maximum apparent brightness of new comets with any degree of certainty is difficult, Hale–Bopp met or exceeded most predictions when it passed perihelion on April 1, 1997. It was visible to the naked eye for a record 18 months, twice as long as the previous record holder, the Great Comet of 1811. Accordingly, Hale–Bopp was dubbed the Great Comet of 1997.
Eilmer of Malmesbury
If Eilmer had seen Halley's comet seventy-six years earlier in 989, he could have been born about 984, making him about five or six years old when he first saw the comet, old enough to remember it. However the periodicity of comets was probably unknown in Eilmer's time, and so his remark "It is long since I saw you" could have referred to a different, later comet. Since it is known that Eilmer was an "old man" in 1066, and that he had made the flight attempt "in his youth", the event is placed some time during the early 11th century, perhaps in its first decade.
Timeline of astronomy
Edmond Halley calculates that the comets recorded at 76-year intervals from 1456 to 1682 are one and the same. He predicts that the comet will return again in 1758. When it reappears as expected, the comet is named in his honor.
Hills cloud
Comet McNaught, discovered on 7 August 2006 in Australia by Robert H. McNaught, became one of the brightest comets of recent decades, with an aphelion of 4,100 AU. Finally, one of the farthest-known comets is Comet West, discovered by Danish astronomer Richard Martin West at the La Silla Observatory in Chile on 10 August 1975; it reaches 13,560 AU.
Halley's Comet
The 141 AD apparition was recorded in Chinese chronicles. It was also recorded in the Tamil work "Purananuru", in connection with the death of the south Indian Chera king Yanaikatchai Mantaran Cheral Irumporai.
27P/Crommelin
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.
Thomas Bopp
Thomas Joel Bopp (October 15, 1949 – January 5, 2018) was an American amateur astronomer best known as the co-discoverer of comet Hale–Bopp (with Alan Hale) in 1995. At the time of the comet discovery he was a manager at a construction materials factory and an amateur astronomer. On the night of July 22, Bopp was observing the sky with friends in the Arizona desert when he made the discovery. It was the first comet he had observed and he was using a borrowed, home-built telescope. Hale and Bopp both discovered the comet by chance at approximately the same time.
Alan Hale (astronomer)
Comet Hale–Bopp, originally labeled C/1995 O1, and sometimes called "the Great Comet of 1997", became one of the most-viewed comets in human history, and the brightest comet seen since Comet West in 1976, appearing 1000 times brighter than Comet Halley did at the same distance.
Biela's Comet
The comet appeared as predicted during its 1832 apparition, when it was first recovered by John Herschel on 24 September. The orbital elements and ephemeris calculated by Olbers for this return created something of a popular sensation, as they showed that the comet's coma would likely pass through the Earth's orbit during a close approach on October 29. Subsequent predictions, in the media of the time, of the Earth's likely destruction overlooked the fact that the Earth itself would not reach this point until November 30, a month later, as pointed out by François Arago in an article designed to allay public fears. Despite this, the fact that Biela's Comet was the only comet known to intersect the Earth's orbit was to make it of particular interest, both to astronomers and the public, during the 19th century.
Archaeoastronomy
Some comets are predictable, most famously Halley's Comet. Yet as a class of object they remain unpredictable and can appear at any time. Some have extremely lengthy orbital periods which means their past appearances and returns cannot be predicted. Others may have only ever passed through the Solar System once and so are inherently unpredictable.
Halley's Comet
The 1910 visitation is also recorded as being the travelling companion of Hedley Churchward, the first known English Muslim to make the Haj pilgrimage to Mecca. However, his explanation of its scientific predictability did not meet with favour in the Holy City.
Comet Holmes
Comet Holmes (official designation: 17P/Holmes) is a periodic comet in the Solar System, discovered by the British amateur astronomer Edwin Holmes on November 6, 1892. Although normally a very faint object, Holmes became notable during its October 2007 return when it temporarily brightened by a factor of about half a million, in what was the largest known outburst by a comet, and became visible to the naked eye. It also briefly became the largest object in the Solar System, as its coma (the thin dissipating dust ball around the comet) expanded to a diameter greater than that of the Sun (although its mass remained minuscule).
Comet Hale–Bopp
Its lengthy period of visibility and extensive coverage in the media meant that Hale–Bopp was probably the most-observed comet in history, making a far greater impact on the general public than the return of Halley's Comet in 1986, and certainly seen by a greater number of people than witnessed any of Halley's previous appearances. For instance, 69% of Americans had seen Hale–Bopp by April 9, 1997.
Heinrich Wilhelm Matthias Olbers
In July 1804 the young Friedrich Wilhelm Bessel contacted Olbers to get his opinion of Bessel's treatise on orbit calculation of Halley's comet. Olbers noticed the outstanding quality of this work and arranged for its publication.
Christian Gärtner
In December 1758 (simultaneously with Johann Georg Palitzsch) Gärtner observed the return of Halley's Comet, predicted by Edmond Halley in 1705.
Halley's Comet
"Giotto" provided the first evidence in support of Fred Whipple's "dirty snowball" hypothesis for comet construction; Whipple postulated that comets are icy objects warmed by the Sun as they approach the inner Solar System, causing ices on their surfaces to sublimate (change directly from a solid to a gas), and jets of volatile material to burst outward, creating the coma. "Giotto" showed that this model was broadly correct, though with modifications. Halley's albedo, for instance, is about 4%, meaning that it reflects only 4% of the sunlight hitting it; about what one would expect for coal. Thus, despite appearing brilliant white to observers on Earth, Halley's Comet is in fact pitch black. The surface temperature of evaporating "dirty ice" ranges from at higher albedo to at low albedo; Vega 1 found Halley's surface temperature to be in the range . This suggested that only 10% of Halley's surface was active, and that large portions of it were coated in a layer of dark dust that retained heat. Together, these observations suggested that Halley was in fact predominantly composed of non-volatile materials, and thus more closely resembled a "snowy dirtball" than a "dirty snowball".
Yale University Observatory
Yale's first observatory, the Atheneum, was founded in 1830, situated in a tower. From 1830 it housed Yale's first refractor, a Dollond donated by Sheldon Clark. It was the largest in the United States at the time. With this telescope Olmsted and Elias Loomis made the first American sighting of the return of Halley's Comet in 1835. (August 31; seen in Europe August 6, but no news of this had reached America). The telescope was mounted on casters and moved from window to window, but it could not reach altitudes much over 30 deg above the horizon.
38P/Stephan–Oterma
38P/Stephan–Oterma (also known as Comet Stephan–Oterma) is a periodic comet with an orbital period of 38 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years). It was discovered in January 1867, by Jérôme Eugène Coggia at Marseilles Observatory, France.
Halley's Comet
During its 1986 apparition, Halley's Comet became the first comet to be observed in detail by spacecraft, providing the first observational data on the structure of a comet nucleus and the mechanism of coma and tail formation. These observations supported a number of longstanding hypotheses about comet construction, particularly Fred Whipple's "dirty snowball" model, which correctly predicted that Halley would be composed of a mixture of volatile ices—such as water, carbon dioxide, and ammonia—and dust. The missions also provided data that substantially reformed and reconfigured these ideas; for instance, it is now understood that the surface of Halley is largely composed of dusty, non-volatile materials, and that only a small portion of it is icy.
Giovanni Battista Audiffredi
The predicted reappearance in the middle of the century of Halley's comet intensified scientific interest in cometic orbits. The epoch was favored with a number of brilliant objects of this kind, and that of 1769 distinguished itself by its great nucleus and by the tail which stretched over more than half the sky. Audiffredi took observations of the positions of the comet and published his results under the title, "Dimostrazione della stazione della cometa, 1769" (1770).
Anders Johan Lexell
After that, Lexell spent most of his effort on comet astronomy (though his first paper on calculating the orbit of a comet is dated 1770). In the next ten years he calculated the orbits of all the newly discovered comets, among them the comet which Charles Messier discovered in 1770. Lexell calculated its orbit, showed that the comet had had a much larger perihelion before the encounter with Jupiter in 1767 and predicted that after encountering Jupiter again in 1779 it would be altogether expelled from the inner Solar System. This comet was later named Lexell's Comet.
Halley's Comet
Halley's calculations enabled the comet's earlier appearances to be found in the historical record. The following table sets out the astronomical designations for every apparition of Halley's Comet from 240 BC, the earliest documented widespread sighting. For example, "1P/1982 U1, 1986 III, 1982i" indicates that for the perihelion in 1986, Halley was the first period comet known (designated 1P) and this apparition was the first seen in half-month U (the second half of October) in 1982 (giving 1P/1982 U1); it was the third comet past perihelion in 1986 (1986 III); and it was the ninth comet spotted in 1982 (provisional designation 1982i). The perihelion dates of each apparition are shown. The perihelion dates farther from the present are approximate, mainly because of uncertainties in the modelling of non-gravitational effects. Perihelion dates of 1531 and earlier are in the Julian calendar, while perihelion dates 1607 and after are in the Gregorian calendar.
Space exploration
Although many comets have been studied from Earth sometimes with centuries-worth of observations, only a few comets have been closely visited. In 1985, the "International Cometary Explorer" conducted the first comet fly-by (21P/Giacobini-Zinner) before joining the Halley Armada studying the famous comet. The "Deep Impact" probe smashed into 9P/Tempel to learn more about its structure and composition and the "Stardust" mission returned samples of another comet's tail. The "Philae" lander successfully landed on Comet Churyumov–Gerasimenko in 2014 as part of the broader "Rosetta" mission.
Comet Encke
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.
C/1760 A1
Messier came up against opposition from Navy astronomer Joseph Nicholas Delisle, who had employed Messier from October 1751, because Delisle would not publish the discovery Messier had made. This was a continuation of the mistrust that had developed between Messier and Delisle because Delisle had been slow to publish work done by Messier in 1759; Messier had independently rediscovered Halley's Comet on 21 January 1759 but because Messier had doubted the correctness of Delisle's path, Delisle instructed Messier to continue observing the comet and refused to announce his discovery. Delisle apparently later changed his mind and announced the discovery on 1 April 1759, but other French astronomers discredited Delisle's claim, labelling the discovery an April Fools' joke. Delisle retired in 1760.
Observational history of comets
By the middle of the twentieth century, this model suffered from a number of shortcomings: in particular, it failed to explain how a body that contained only a little ice could continue to put on a brilliant display of evaporating vapor after several perihelion passages. In 1950, Fred Lawrence Whipple proposed that rather than being rocky objects containing some ice, comets were icy objects containing some dust and rock. This "dirty snowball" model soon became accepted and appeared to be supported by the observations of an armada of spacecraft (including the European Space Agency's "Giotto" probe and the Soviet Union's "Vega 1" and "Vega 2") that flew through the coma of Halley's Comet in 1986, photographed the nucleus, and observed jets of evaporating material.
Observational history of comets
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.
Gunvalkyrie
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's Comet
Halley's 1910 apparition is distinct from the Great Daylight Comet of 1910, which surpassed Halley in brilliance and was actually visible in broad daylight for a short period, approximately four months before Halley made its appearance.
Khagol Mandal
The organization was founded a few years before the arrival of the Halley's comet and succeeded in its intent to generate curiosity among the general public about the comet.