Halley's Comet or Comet Halley, officially designated 1P/Halley, is a short-period comet visible from Earth every 75–76 years. 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 can appear twice in a human lifetime. Halley last appeared in the inner parts of the Solar System in 1986 and will next appear in mid-2061. 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, Greeks, Babylonian, and medieval European chroniclers, but, at those times, were not recognized as reappearances of the same object.
Introduction
Halley's Comet
Halley's Comet | Introduction
Halley's Comet or Comet Halley, officially designated 1P/Halley, is a short-period comet visible from Earth every 75–76 years. It is a short-period comet visible from Earth every 75–76 years. 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 can appear twice in a human lifetime. It is a short-period comet visible from Earth every 75–76 years. Halley's Comet or Comet Halley, officially designated 1P/Halley, is a short-period comet visible from Earth every 75–76 years.
who told the magi to follow the star
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Matthew's account suggests that the Magi knew from the star that the "king of the Jews" had been born before they arrived in Jerusalem
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who is this magi?
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The Magi (often translated as "wise men"), but is more accurately astrologers.
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who is this star?
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Other writers highly 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
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what is this aforesaid comet?
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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.
Halley's Comet | 1066
This appearance of the comet is also noted in the "Anglo-Saxon Chronicle". Eilmer of Malmesbury may have seen Halley previously in 989, as he wrote of it in 1066: "You've come, have you? ... You've come, you source of tears to many mothers, you evil. I hate you! It is long since I saw you; but as I see you now you are much more terrible, for I see you brandishing the downfall of my country. I hate you!" The Irish "Annals of the Four Masters" recorded the comet as "A star [that] appeared on the seventh of the Calends of May, on Tuesday after Little Easter, than whose light the brilliance or light of The Moon was not greater; and it was visible to all in this manner till the end of four nights afterwards." Chaco Native Americans in New Mexico may have recorded the 1066 apparition in their petroglyphs.
Halley's Comet | 1066
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 Opal | Introduction
4P/Faye (also known as Faye's Comet or Comet Faye) is a periodic Jupiter-family comet discovered in November 1843 by Hervé Faye at the Royal Observatory in Paris. It last came to perihelion (closest approach to the Sun) on May 29, 2014, and will next come to perihelion on September 8, 2021. The comet was first observed by Faye on 23 November, but bad weather prevented its confirmation until the 25th. It was so faint that it had already passed perihelion about a month before its discovery, and only a close pass by the Earth had made it bright enough for discovery.
4P/Faye | Introduction
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. On August 21, 1919, the comet was recovered by Joel Hastings Metcalf (Camp Idlewild, Vermont, United States) as 8th magnitude. Additional discoveries were made by Edward Barnard (Yerkes Observatory, Wisconsin, United States) on August 22, Michel Giacobini (Paris, France), Ostrovlev (Theodosia, Crimea) and Selavanov (Saint Petersburg).
23P/Brorsen–Metcalf | Introduction
The Great Comet of 1106 AD was a gigantic comet noticed by observers from all over the world. On 2 February 1106 AD, a star was reported to have appeared next to the sun, about a degree from it. It seems to have diminished in brightness after this apparition, with a rather faint, unremarkable nucleus after perihelion, but its tail grew enormously and on February 7 Japanese observers said the extremely bright white tail stretched about 100 degrees across the night sky, which was also reported to have been branching into multiple tails. On February 9, it dimmed slightly, but its tail was still exceedingly bright, measuring 60 degrees long and 3 degrees across.
Kreutz sungrazer | Great Comet of 1106 AD
The only surviving record of the 164 BC apparition is found on two fragmentary Babylonian tablets, now owned by the British Museum. 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.
Halley's Comet | Before 1066
Images showed Halley's nucleus to be a dark peanut-shaped body, 15 km long, 7 km to 10 km wide. Only 10% of the surface was active, with at least three outgassing jets seen on the sunlit side. Analysis showed the comet formed 4.5 billion years ago from volatiles (mainly ice) that had condensed onto interstellar dust particles. It had remained practically unaltered since its formation. Measured volume of material ejected by Halley: "Giotto" found Halley's nucleus was dark, which suggested a thick covering of dust.
Giotto (spacecraft) | Scientific results
On July 14 the Christians gained a small advantage, and on the twenty-first and twenty-second the Turks were put to flight. In the same year Halley's comet appeared. In Italy it was first seen in June. Towards the end of the month it was still visible for three hours after sunset, causing great excitement everywhere by its extraordinary splendour. It naturally attracted the attention of astrologers as may appear from the long "judicium astrologicum" by Avogario, of Ferrara, dated June 17, 1467; it was found again by Celoria among the manuscripts of Paolo Toscanelli, who had copied it himself. The comet was seen till July 8.
Bartolomeo Platina | Halley's comet
Halley's Comet or Comet Halley, officially designated 1P/Halley, is a short-period comet visible from Earth every 75–76 years. 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 can appear twice in a human lifetime. Halley last appeared in the inner parts of the Solar System in 1986 and will next appear in mid-2061. 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, Greeks, Babylonian, and medieval European chroniclers, but, at those times, were not recognized as reappearances of the same object.
Halley's Comet | Introduction
161P/Hartley–IRAS is a periodic comet with an orbital period of 21 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years). This was one of six comets discovered by the infrared space telescope IRAS, in 1983.
161P/Hartley–IRAS | Introduction
He read the apparition as a cometary portent of doom foreshadowing the imminent fall of Sultan Zayn al-Abidin (AD 1418/1420–1470).
Halley's Comet | 1456
The comet was followed until June 1857, and the orbit was then well established. Observers reported that the comet had a bright, almost star-like nucleus.
5D/Brorsen | Introduction
On 12 February 1991, at a distance of from the Sun, Halley displayed an outburst that lasted for several months, releasing a cloud of dust across. The outburst likely started in December 1990, and then the comet brightened from magnitude 24.3 to magnitude 18.9. Halley was most recently observed in 2003 by three of the Very Large Telescopes at Paranal, Chile, when Halley's magnitude was 28.2. The telescopes observed Halley, at the faintest and farthest any comet has ever been imaged, in order to verify a method for finding very faint trans-Neptunian objects. Astronomers are now able to observe the comet at any point in its orbit.
Halley's Comet | After 1986
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 "", 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. By 1706 Halley had learned Arabic and completed the translation started by Edward Bernard of Books V-VII of Apollonius's "Conics" from copies found at Leiden and the Bodleian Library at Oxford.
Edmond Halley | Life as an academic
From ancient sources, such as Chinese oracle bones, it is known that comets have been noticed by humans for millennia. Until the sixteenth century, comets were usually considered bad omens of deaths of kings or noble men, or coming catastrophes, or even interpreted as attacks by heavenly beings against terrestrial inhabitants. In the 11th century Bayeux Tapestry, Halley's Comet is depicted portending the death of Harold and the triumph of the Normans at the Battle of Hastings. According to Norse Mythology, comets were actually a part of the Giant Ymir's skull. According to the tale, Odin and his brothers slew Ymir and set about constructing the world (Earth) from his corpse.
Comet | Early observations and thought
The 1145 apparition was recorded by the monk Eadwine. The 1986 apparition exhibited a fan tail similar to Eadwine's drawing. Some claim that Genghis Khan was inspired to turn his conquests toward Europe by the 1222 apparition. The 1301 apparition may have been seen by the artist Giotto di Bondone, who represented the Star of Bethlehem as a fire-colored comet in the Nativity section of his Arena Chapel cycle, completed in 1305. Its 1378 appearance is recorded in the "Annales Mediolanenses" as well as in East Asian sources.
Halley's Comet | 1145–1378
Other writers highly 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.
Star of Bethlehem | Comet
In 2134, Halley is expected to pass within of Earth. Its apparent magnitude is expected to be −2.0.
Halley's Comet | 2134
It was said that the "prodigy of a hairy star" had brought upon his illness, and slipped away when the job was finished. This comet was likewise observed in China, and the descriptions agree with the statements of the European historians.
Great Comet of 1264 | Introduction
It was traveling on a hyperbolic orbit, that is, traveling fast enough to escape from the Solar System entirely, hence implying that it will never be seen again by earthbound observers. Observations of the comet over a period of 520 days allowed precise orbital elements to be computed. However, the distribution of the orbital elements showed a wavy pattern that suggested a non-gravitational influence. Alternatively, the comet may have originated from interstellar space rather than from the Oort cloud. When an orbital solution is computed that includes non-gravitational forces that vary as the inverse square of the heliocentric distance, somewhat different values are derived (see the Marsden (1970) column in the table below).
Comet Arend–Roland | Properties
The year 1910 saw considerable media interest in the predicted return of Halley's Comet, which reached perihelion on April 20. The appearance of the Daylight Comet several months earlier therefore came as something of a surprise, and made an extremely strong impression on an expectant public; when Halley's Comet returned again in 1986, many older people's accounts of having seen it in 1910 clearly referred to the Daylight Comet instead. Owing to a "telephonic error", the comet was initially reported as being named Drake's Comet, though once the error was realised the press afterwards referred to it as the Daylight Comet or Sunset Comet, as no single individual was credited with its discovery.
Great January Comet of 1910 | Halley's Comet and the Daylight Comet
In December 2023, Halley's Comet is calculated to reach the farthest point in its orbit from Sun.
Halley's Comet | After 1986
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. The first certain appearance of Halley's Comet in the historical record is a description from 240 BC, in the Chinese chronicle "Records of the Grand Historian" or "Shiji", which describes a comet that appeared in the east and moved north.
Halley's Comet | Before 1066
He likewise ordered, to move God by continual entreaty, that notice should be given by the bells to call the faithful at midday to aid by their prayers those engaged in battle with the Turk. 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. Halley's apparition of 1456 was also witnessed in Kashmir and depicted in great detail by Śrīvara, a Sanskrit poet and biographer to the Sultans of Kashmir.
Halley's Comet | 1456
The magnitude of the comet declined after 1926, and it was not until 1953 that it has been observed on every return.
15P/Finlay | Description
Confident that these three apparitions had been three appearances of the same comet, he predicted that it would appear again in 1758–9. 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. When the comet returned as predicted, it became known as Halley's Comet (with the modern designation of 1P/Halley). It will next appear in 2061. In the 19th century, the Astronomical Observatory of Padova, was an epicenter in the observational study of comets. Led by Giovanni Santini (1787-1877) and followed by Giuseppe Lorenzoni (1843-1914), this observatory was devoted to classical astronomy, mainly to the new comets and planets orbit calculation, with the goal of compiling of a catalog of almost ten thousand stars.
Comet | Orbital studies
The Great Comet seen in the winter of 372–371 BC was an extremely bright comet thought to be the progenitor of the entire Kreutz sungrazer family. It was observed by Aristotle and Ephorus during the period in which it was visible to the naked eye. It was reported to have had an extremely long, extremely bright, prominent tail with a reddish colour, as well as a nucleus brighter than any star in the night sky. Ephorus also reported the comet to have split into two fragments: a larger fragment which is now thought to have returned in 1106 AD as another spectacular sungrazer, as well as another, much smaller fragment.
Kreutz sungrazer | Great Comet of 371 BC
The Soviet Vega 1 started returning images of Halley on 4 March 1986, and the first ever of its nucleus, and made its flyby on 6 March, followed by Vega 2 making its flyby on 9 March. On 14 March, the "Giotto" space probe, launched by the European Space Agency, made the closest pass of the comet's nucleus. There were also two Japanese probes, "Suisei" and "Sakigake". The probes were unofficially known as the Halley Armada.
Halley's Comet | 1986
The comet has not been observed during the following perihelion passages:
18D/Perrine–Mrkos | Introduction
Aristotle's Comet was a great comet which Aristotle saw in the winter of 373–372 BC.
Aristotle's Comet | Introduction
Comet Arend or 50P/Arend is a periodic comet in the Solar System which was discovered on October 4, 1951. It was discovered by astronomer Sylvain Julien Victor Arend at the Royal Observatory of Belgium located in the municipality of Uccle. The comet was illustrated at approximately a magnitude of 14 and also exhibited a nucleus within a coma 14 arc seconds across. From its discovery, the comet has had 7 perihelions with its last return of Earth recorded on November 1, 2007. The comet's next perihelion will be in the year 2016.
50P/Arend | Introduction
Possibly also its radiance passes, but not its body." Again, Samuel says: "But for the warmth of Orion, the earth could not exist, because of the frigidity of Scorpio; furthermore, Orion lies near Taurus, with which the warm season begins. The comet, because of its tail, is called "kokba de-shabbiṭ". (rodstar). Rabbi Joshua ben Hananiah (about 100), declared that a star appears once every seventy years and leads mariners astray, hence they should at such time lay in a larger store of provisions. Rapoport endeavors to prove that the path of Halley's comet had been computed by a wise rabbi.
Hebrew astronomy | Fixed stars and comets
The dating of the manuscript has been much discussed, mainly on stylistic grounds (regarding both the script and the illustrations), within the broad range 1130–1170. On folio 10 there is a marginal drawing of a comet, with a note in Old English (in which it is a "hairy star") that it is an augury; following the comet of 1066 the English evidently took comets seriously. This was thought to relate to the appearance of Halley's Comet in 1145, but another of 14 May 1147 is recorded in the Christ Church Annals, and the 1145 one is not. There were further comets recorded in 1165 and 1167, so the evidence from astronomy has not settled the question.
Eadwine Psalter | Scribes, artists and history
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.
Aegospotami | Introduction
At Markree Observatory in Ireland, a E. J. Cooper used a Cauchoix of Paris lens telescope with an aperture of 13.3 (~34 cm) inches to sketch Halley's comet in 1835. The comet was also sketched by F.W. Bessel. Streams of vapour observed during the comet's 1835 apparition prompted astronomer Friedrich Wilhelm Bessel to propose that the jet forces of evaporating material could be great enough to significantly alter a comet's orbit. An interview in 1910, of someone who was a teenager at the time of the 1835 apparition had this to say:
Halley's Comet | 1835
In the decades that followed, more refined mathematics would be worked on, notable by Paris Observatory; the work on Halley also provided a boost to Newton and Kepler's rules for celestial motions. (See also #Computation of orbit)
Halley's Comet | 1531–1759
Comet Borrelly or Borrelly's Comet (official designation: 19P/Borrelly) is a periodic comet, which was visited by the spacecraft Deep Space 1 in 2001. The comet last came to perihelion (closest approach to the Sun) on May 28, 2015 and will next come to perihelion on February 1, 2022. The comet's nucleus, seen in the adjacent image, is particularly notable for being shaped like a bowling pin.
19P/Borrelly | Introduction
Jérôme Lalande recommended her along with the mathematician Alexis Clairaut to calculate the predicted return of Halley's Comet, as well as to calculate the attraction of Jupiter and Saturn of the Halley's comet. The team worked on the calculations for more than six months straight, barely stopping for food. In November 1758, the team presented their conclusion that the comet would arrive on 13 April 1759. They were almost correct, as the comet arrived on 13 March 1759. As a result of their calculations, this was the first time scientists had successfully predicted when the comet would cross the perihelion, i.e.
Nicole-Reine Lepaute | Halley's Comet
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°.) Owing 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.
Halley's Comet | Orbit and origin
This figure is the highest yet measured in a comet.
Deuterium | Introduction
Newton later changed his mind, however, and then, with Edmond Halley's help, purloined some of Flamsteed's data to indeed verify this was the case without giving Flamsteed credit.
Great Comet of 1680 | Overview
The comet was recovered on November 26, 1845, by Francesco de Vico. Initially a small, faint nebulosity, subsequent observations showed that something remarkable had happened to it. Matthew Fontaine Maury, observing on 14 January 1846, noted that an apparent companion was located 1 arc minute north of the comet. After this announcement many astronomers began observing the comet, and noted that the two elements (usually referred to as "Comet A" and "Comet B" in modern nomenclature) alternated in brightness, developing parallel tails as they approached perihelion. Some observations indicated an "archway of cometary matter" extending between the two nuclei, which might suggest that the comet had split into many more pieces than two, but were simply too faint to be observed individually.
Biela's Comet | Disintegration
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.
Halley's Comet | Orbit and origin
C/2001 Q4 (NEAT) is a comet with an unusual, almost perpendicular retrograde orbit which brings it into the inner solar system by a deeply southward path. It initially emerged from its remote home spending most of its time near the south celestial pole. This comet was discovered on August 24, 2001 by the Near-Earth Asteroid Tracking program (NEAT). In 2004, residents of the southern hemisphere had the opportunity to watch the comet gradually brighten as it raced toward perihelion. On May 6, 2004 the comet approached within 0.32 AU of the Earth. Beginning in early May, the comet started racing north and burst into view in the northern hemisphere when it had reached almost maximum brightness.
C/2001 Q4 (NEAT) | Introduction
43P/Wolf–Harrington is a periodic comet discovered on December 22, 1924, by Max Wolf in Heidelberg, Germany. In 2019 it passed within of Jupiter, which lifted the perihelion point and increased the orbital period to 9 years. During the 1997 apparition the comet reached an apparent magnitude a little bit brighter than 12. The comet had an unfavorable apparition in 2010, because during perihelion (closest approach to the Sun), the comet was only 10 degrees from the Sun as seen from Earth. The comet was not more favorably positioned in the sky until mid October 2010.
43P/Wolf–Harrington | Introduction
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. 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. If Halley was once a long-period comet, it is likely to have originated in the Oort cloud, a sphere of cometary bodies that has an inner edge of 20,000–50,000 AU.
Halley's Comet | Orbit and origin
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).
Halley's Comet | Apparitions
As she carried it, she felt it glow and take fire, and loosed it from her breast: it climbed higher than the moon, and drawing behind it a fiery tail, shone as a star. It has been argued recently that the idea of Augustus's use of the comet for his political aims largely stems from this passage. In Shakespeare’s "Julius Caesar" (1599), Caesar's wife remarks on the fateful morning of her husband's murder: "When beggars die there are no comets seen. The heavens themselves blaze forth the death of princes."
Caesar's Comet | In literature
C/1769 P1 (Messier) is a long-period comet that was visible to the naked eye at its last apparition in 1769. Because of its outstanding brightness it is called a great comet.
C/1769 P1 | Introduction
35P/Herschel–Rigollet is a periodic comet with an orbital period of 155 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years). It was discovered by Caroline Herschel (Slough, United Kingdom) on 1788-12-21. Given that the comet has a 155 year orbit involving asymmetric outgassing, and astrometric observations in 1939 were not as precise as modern observations, predictions for the next perihelion passage in 2092 vary by about a month.
35P/Herschel–Rigollet | Introduction
The Great Comet of 1556 is called the comet of Charles V. When the Emperor first caught sight of it he stood aghast, and exclaimed: "By this dread sign my fates do summon me". Charles had long meditated about retiring from the world he had conquered and crushed. Regarding the comet as a sign of Heaven's command to do so, he hastened towards the peaceful monastery of St. Juste, Placentia. An anonymous English treatise on ""Blazing Stares"" (1618) spoke of the comet as follows :
Great Comet of 1556 | Charles V comet
By December 2014, the comet had brightened to roughly magnitude 7.4, making it a small telescope and binoculars target. By mid-December, the comet was visible to the naked eye for experienced observers with dark skies and keen eyesight. On 28–29 December 2014, the comet passed 1/3° from globular cluster Messier 79. In January 2015, it brightened to roughly magnitude 4, and became one of the brightest comets located high in a dark sky since comet (Hale-Bopp) in 1997. On 7 January 2015, the comet passed from Earth. It crossed the celestial equator on 9 January 2015, becoming better seen from the Northern Hemisphere.
C/2014 Q2 (Lovejoy) | History
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 and 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. While he had personally observed the comet around perihelion in September 1682, Halley died in 1742 before he could observe its predicted return.
Halley's Comet | Computation of orbit
The comet's periodicity was first determined in 1705 by English astronomer Edmond Halley, after whom it is now named. 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.
Halley's Comet | Introduction
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.
Halley's Comet | Structure and composition
100P/Hartley, also known as Hartley 1, is a periodic, Jupiter family comet in the Solar System. On 29 April 2164 the comet will pass from Earth.
100P/Hartley | Introduction
When the members gathered on the night before the comet was supposed to enter Earth's orbit, nobody mentioned the comet. Jensen later said that the massive earthquakes were fulfilled by a "spiritual earthquake" when one of his important followers defected and left him.
Leland Jensen | Halley's Comet
It has been a long time since comet nuclei could be imagined as frozen snowballs. Whipple had already postulated a separate crust and interior. Before Halley's 1986 apparition, it appeared that an exposed ice surface would have some finite lifetime, even behind a coma. Halley's nucleus was predicted to be dark, not bright, due to preferential destruction/escape of gases, and retention of refractories. The term "dust mantling" has been in common use since more than 35 years. The Halley results exceeded even these- comets are not merely dark, but among the darkest objects in the Solar System Furthermore, prior dust estimates were severe undercounts.
Comet nucleus | "Icy dirtball"
In 1963, Brian G. Marsden used a computer to link the 1844 and 1894 sightings and calculated a favourable return in 1965. The comet was subsequently recovered by Arnold Klemola (Yale-Columbia Southern Observatory, Argentina) on June 30, 1965, at magnitude 17. In 1968 the comet passed close to Jupiter which increased the perihelion distance and orbital period, the magnitude dropped and the comet was not observed for subsequent predictions, in 1995 it was again considered lost.
54P/de Vico–Swift–NEAT | Third discovery (1965)
The comet was discovered on June 14, 1770, in the constellation Sagittarius by Messier, who had just completed an observation of Jupiter and was examining several nebulae. At this time it was very faint, but his observations over the course of the next few days showed that it rapidly grew in size, its coma reaching 27 arcminutes across by June 24: by this time it was of magnitude +2. The comet was also noted by several other astronomers. The comet was observed in Japan. Surviving records identify it as an astronomical and historical phenomenon. It was observed in the Hejaz in Safar 1184 AH (June 1770), where some believed it to be the comet predicted by the poet al-Fasi, portending future events.
Lexell's Comet | Discovery
Comet Gale is a periodic comet in the Solar System discovered by Walter Frederick Gale (Sydney, Australia) on June 7, 1927. The second apparition was calculated for 1938, but Gale failed to find it; however, it was recalculated by Leland E. Cunningham who later recovered it for that year. The 1949 apparition was never detected, and due to unfavourable conditions ever since it has never been recovered and it remains a lost comet.
34D/Gale | Introduction
10P/Tempel, also known as Tempel 2, is a periodic Jupiter-family comet with a 5 year orbital period. It was discovered on July 4, 1873 by Wilhelm Tempel. The next perihelion passage is 24 March 2021 when the comet will have a solar elongation of 30 degrees at approximately apparent magnitude 11. Closest approach to Earth during the 2021 passage will not occur until many months later on 3 November 2021 at a distance of . The comet nucleus is estimated to be roughly the size of Halley's Comet at 10.6 kilometers in diameter with a low albedo of 0.022. The nucleus is dark because hydrocarbons on the surface have been converted to a dark, tar like substance by solar ultraviolet radiation.
10P/Tempel | Introduction
The comet (or "broom star") was also observed in Chinese astronomy, where it is noted that it was visible even at midday. The 15th century English Chronicler, Warkworth, left a detailed account of the comet's appearance and disappearance from the night sky of England.
Comet of 1472 | Introduction
The next perihelion of Halley's Comet is 28 July 2061, when it will 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.
Halley's Comet | 2061
the point of the comet orbit closest to the Sun. Clairault did not recognize her work at all in his work, which upset Lalande who considered Lepaute the "most distinguished female French astronomer ever." Jérôme Lalande acknowledged her help in an article.
Nicole-Reine Lepaute | Halley's Comet
ICE transited between the Sun and Comet Halley in late March 1986, when other spacecraft were near the comet on their early-March comet rendezvous missions. (This "Halley Armada" included Giotto, Vega 1 and 2, Suisei and Sakigake.) ICE flew through the tail; its minimum distance to the comet nucleus was . For comparison, Earth's minimum distance to Comet Halley in 1910 was .
International Cometary Explorer | Halley encounter
The oldest picture of a comet is that of Halley's Comet in the Nuremberg Chronicle for AD 684. One very famous recording of a comet is the appearance of Halley's Comet as a terrifying omen on the Bayeux Tapestry, which records the Norman conquest of England in AD 1066. Meteors and comets were of great importance to the native inhabitants of Mexico. Meteors were alternatively viewed as arrows of stellar gods, as their cigar butts, and even as their excrement. The arrows could hit animals or people and were feared when walking at night. Comets were conceived as smoking stars and as bad omens, e.g., announcing the death of a ruler.
Observational history of comets | Early observations and thought
68P/Klemola or Klemola's Comet is a periodic comet, which belongs to Jupiter's comet family, that was discovered in 1965 by American astronomer in Argentinian "Yale-Columbia Southern Station". Its orbital period is 10.82 years. It was observed at the next predicted apparition by Gérard Sause at the Observatoire de Haute Provence, France on 6 August 1976 with a brightness of magnitude 12. It was successfully observed in 1987 when J. Gibson of the Palomar Observatory, California, obtained images with the 1.5-meter reflector on 16 February. It appeared essentially stellar, with a faint magnitude of 19. It was observed again on 29 March 1997 by Carl W.
68P/Klemola | Introduction
Under dark skies the comet was a naked eye object. Perihelion was late January 2008, and as of February was visible telescopically to Southern Hemisphere observers in the constellation Eridanus. On December 30, 2007 it was in close conjunction with spiral galaxy M33. On January 1, 2008 it passed Earth at a distance of . Predictions that the 2007 Ursid meteor shower could be expected to be stronger than usual due to the return of the comet, did not appear to materialize, as counts were in the range of normal distribution.
8P/Tuttle | 2008 perihelion
A great comet is a comet that becomes exceptionally bright. There is no official definition; often the term is attached to comets such as Halley's Comet, which during certain appearances are bright enough to be noticed by casual observers who are not looking for them, and become well known outside the astronomical community. Great comets are rare; on average, only one will appear in a decade. Although comets are officially named after their discoverers, great comets are sometimes also referred to by the year in which they appeared great, using the formulation "The Great Comet of ...", followed by the year.
Great comet | Introduction
However a few of these may be Interstellar comets Comets observed in early times, which were later found to be observations of numbered periodic comets, are marked with [periodic comet number]/[comet name]. For instance, X/-239 K1 was an appearance of Halley's comet in 239 BC, and as such is written as 1P/-239 K1. A significant portion of the comets passing closer than 0.01 AU to the Sun are fragments of the comet of 371 BC, which fractured into several pieces on the 326 AD perihelion, which further fractured into thousands of pieces on the 1106 AD perihelion, creating the cometary group now known as the Kreutz sungrazers.
List of comets by type | Ejection-trajectory comets
The comet may be an echo of the Star of Bethlehem from the biblical nativity story, but could also be a reference to the science of astronomy and the place of humans in the universe.
Pegwell Bay, Kent – a Recollection of October 5th 1858 | Painting
Comet Halley is commonly pronounced , rhyming with "valley", or , rhyming with "daily". Colin Ronan, one of Edmond Halley's biographers, preferred , rhyming with "crawly". Spellings of Halley's name during his lifetime included "Hailey, Haley, Hayley, Halley, Hawley", and "Hawly", so its contemporary pronunciation is uncertain, but current bearers of this surname appear to prefer the version that rhymes with "valley".
Halley's Comet | Pronunciation
X/1106 C1, also known as the Great Comet of 1106, was a great comet that appeared on 2 February 1106, and was observed across the world from the beginning of February through to mid-March. It was recorded by astronomers in Wales, England, Japan, Korea, China and Continental Europe. It was observed to split into many pieces, forming the Great Comet of 1882, Comet Ikeya–Seki, as well as over 4000 small sungrazing comets observed by the SOHO space telescope. It is a member of the Kreutz Group, known as Subfragment I, a split from an earlier large (~150 km) comet that progressively fragmented under influence of the Sun.
X/1106 C1 | Introduction
Since the comet survived perihelion, it is thought that the nucleus must have been larger, perhaps up to . During the coronal passage, it is believed that a significant fraction of the comet's mass was burned off.
C/2011 W3 (Lovejoy) | Perihelion
The comet was rapidly approaching perihelion when it was first seen. At perihelion, the comet is estimated to have been only 300,000 miles or from the Sun's surface. Subsequent orbital studies have determined that it was a Sungrazing comet, one which passes extremely close to the surface of the Sun. For many hours on either side of its perihelion passage, the comet was easily visible in the daytime sky next to the Sun. It reached an estimated magnitude of −17. Shortly after perihelion was reached on 17 September, the comet transited the Sun. At the Cape, Finlay observed the comet with the aid of a neutral density filter right up until the moment of transit, when the Sun's limb was ""boiling all about it"".
Great Comet of 1882 | Perihelion
C/2014 Q2 (Lovejoy) is a long-period comet discovered on 17 August 2014 by Terry Lovejoy using a Schmidt–Cassegrain telescope. It was discovered at apparent magnitude 15 in the southern constellation of Puppis. It is the fifth comet discovered by Terry Lovejoy. Its blue-green glow is the result of organic molecules and water released by the comet fluorescing under the intense UV and optical light of the Sun as it passes through space.
C/2014 Q2 (Lovejoy) | Introduction
12P/Pons–Brooks is a periodic comet with an orbital period of 71 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years). The next perihelion passage is 20–21 April 2024, with closest approach to Earth being on 2 June 2024. 12P/Pons–Brooks may be the parent body of the December κ-Draconids meteor shower. Comet Pons-Brooks was discovered at Marseilles Observatory in July 1812, and then later recovered in 1883.
12P/Pons–Brooks | Introduction
51P/Harrington is a periodic comet in the Solar System. It was discovered by Robert George Harrington at Palomar Observatory on 14 August 1953 using the Schmidt telescope. It then had a brightness of magnitude 15. In October 1956 its orbit was affected by the planet Jupiter and on its next return in 1960 the brightness had fallen to magnitude 20. By 1980 it had slightly improved to magnitude 18. It has a period of approximately 7 years. In 1987 and 1994 brightness had significantly increased to magnitude 12. In 1994 Jim Scotti at Kitt Peak Observatory observed that the comet had broken up and that two detached pieces were accompanying the main body, which explained the improvement in the brightness.
51P/Harrington | Introduction
In reality, as other astronomers were quick to point out, the gas is so diffused that the world suffered no ill effects from the passage through the tail. 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, The people believe that it indicates calamity such as war, fire, pestilence, and a change of dynasty. In some places on certain days the doors were unopened for half a day, no water was carried and many did not even drink water as it was rumoured that pestilential vapour was being poured down upon the earth from the comet."
Halley's Comet | 1910
The conclusion was that the comet had a thin layer on its surface covering an icy body. Vega 1 made its closest approach on 6 March at around 8,889 kilometers (at 07:20:06 UT) of the nucleus. It took more than 500 pictures via different filters as it flew through the gas cloud around the coma. Although the spacecraft was battered by dust, none of the instruments were disabled during the encounter.
Vega 1 | Halley mission
In Greek and Roman culture, "comet" is an adjective describing the distinctive characteristic of a special star. "Comet star" means "long-haired star", and it was so represented on coins and monuments. Here is an excerpt of an account by Pliny, with parts of a public speech delivered by Augustus about the comet, his father Caesar, and his own destiny:
Temple of Caesar | History
86P/Wild (pronounced "86P/Vilt") is a periodic comet in the Solar System with a current orbital period of 6.84 years. It was discovered on photographic plates exposed on 11/12 April 1980 by Paul Wild of the Astronomical Institute of University of Bern, Switzerland at the nearby Zimmerwald Observatory. He reported the brightness at a magnitude of 15.5 and that the comet was diffuse. He rediscovered it on 7 May 1980 and calculations by Brian G. Marsden estimated that perihelion would take place on 6 October 1980. Syuichi Nakano calculated the next perihelion would be 31 August 1987 and the comet was duly observed by Tom Gehrels and J.
86P/Wild | Introduction
11P/Tempel–Swift–LINEAR is a periodic Jupiter-family comet in the Solar System. Ernst Wilhelm Leberecht Tempel (Marseille) originally discovered the comet on November 27, 1869, it was later observed by Lewis Swift (Warner Observatory) on October 11, 1880, and realised to be the same comet. After 1908 the comet became an unobservable lost comet, but on December 7, 2001, an object was found by the Lincoln Near-Earth Asteroid Research (LINEAR) program, and confirmed by previous images from September 10 and October 17 as being the same comet. The comet was not observed during the 2008 unfavorable apparition because the perihelion passage occurred when the comet was on the far side of the Sun.
11P/Tempel–Swift–LINEAR | Introduction
By the end of 1912 it was recognised as a short period comet estimated to return in 7.1 years, later recalculated as 8 years. The 1919 return was recovered by Gaston Fayet (Paris, France) as magnitude 10.5. The 1927 approach was magnitude 12, but the comet was missed on the 1935 approach. In 1937 it passed close to Jupiter which increased its orbital period slightly. The comet was missed in 1968 and 1976. It was speculated that the increase in brightness in 1952 indicated a problem that led to it vanishing. In 1984, Elizabeth Roemer (Steward Observatory, Arizona, USA) found an image on photographs from 1976.
24P/Schaumasse | Observations
Comet Boethin (officially 85D/Boethin) was a periodic Jupiter-family comet discovered in 1975 by Leo Boethin. It appeared again in January 1986 as expected. Although the comet was next expected at perihelion in April 1997, no observations were reported, and the comet is thought to have disintegrated. It has not been observed since March 1986. The comet might have come to perihelion in late July 2020, but the uncertainty in the comet's position is hundreds of millions of km.
85D/Boethin | Introduction
The comet was discovered on November 29, 1743, by Jan de Munck at Middelburg, and was independently sighted on December 9, 1743 by Klinkenberg at Haarlem, and by Chéseaux from the observatory at Lausanne on December 13. Chéseaux said it lacked a tail and resembled a nebulous star of the third magnitude; he measured the coma as five minutes across. The comet brightened steadily as it approached perihelion. By February 18, 1744, it reportedly was as bright as the planet Venus (with an apparent magnitude of -4.6) and at this time displayed a double tail.
Great Comet of 1744 | Discovery
79P/du Toit–Hartley or du Toit 2 is a periodic comet, now divided into two parts, in the Solar System with an orbital period of 5.06 years. It was originally discovered by Daniel du Toit at the Boyden Observatory, Bloemfontein, South Africa (then administered by Harvard College) on 9 April 1945 with a brightness of apparent magnitude 10. Uncertainties in the calculation of the orbit meant the comet was lost until rediscovered by Malcolm Hartley of the UK Schmidt Telescope Unit, Siding Spring, Australia in 1982, when it was found to have broken into two parts, probably in 1976. Both parts had a brightness of magnitude 17.
79P/du Toit–Hartley | Introduction
Chinese records indicate that, in 188, the comet reached apparent magnitude 0.1. Observation was also recorded in 69 BC, and it was probably visible to the naked eye in 322 BC. In the discovery year of 1862, the comet was as bright as Polaris. After the 1862 observations it was thought that the comet would return between 1979 and 1983, but it didn't show up. However, it had been suggested in 1902 that this was the same comet as that observed by Ignatius Kegler on July 3, 1737, and on this basis Brian Marsden calculated correctly that it would return in 1992.
Comet Swift–Tuttle | Historic observations
It faded rapidly, becoming visible only in telescopes and was last seen on February 17, 1912. The comet sported a tail 8 to 10 degrees in length. In mid-October, the comet was visible in the evening sky together with another bright comet, C/1911 O1 Brooks. Comet Beljawsky is a long-period (non-periodic) comet noteworthy for having a hyperbolic orbit and so it is not expected to return to the inner Solar System again.
C/1911 S3 | Introduction
Hussey achieved some contemporary celebrity as being one of the first people in Britain (along with Sir James South) to see the return of Halley's Comet on 22 August 1835, communicating his subsequent observations with enthusiasm. At the time, Hussey was engaged in publishing a "Catalogue of Comets" in a series of papers for the "Philosophical Magazine".
Thomas John Hussey | Halley's Comet
Halley's periodic returns have been subject to scientific investigation since the 16th century. The three apparitions from 1531 to 1682 were noted by Edmond Halley, enabling him to predict it would return. One key breakthrough occurred when Halley talked with Newton about his ideas of the laws of motion. Newton also helped Halley get Flamsteed's data on the 1682 apparition. By studying data on the 1531, 1607, and 1682 comets, he came to the conclusion these were the same Comet, and presented his findings in 1696. One difficulty was accounting for the effect of the planets, and Jupiter would delay Halley somewhat for 1759.
Halley's Comet | 1531–1759
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.
Comet nucleus | Size
Comet Swift–Tuttle (formally designated 109P/Swift–Tuttle) is a large periodic comet with a 1995 (osculating) orbital period of 133 years that is in a 1:11 orbital resonance with Jupiter. 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 comet nucleus 26 km in diameter. It is the parent body of the Perseid meteor shower, perhaps the best known shower and among the most reliable in performance. The comet made a return appearance in 1992, when it was rediscovered by Japanese astronomer Tsuruhiko Kiuchi and became visible with binoculars.
Comet Swift–Tuttle | Introduction
C/1874 H1 (Coggia) is a famous non-periodic comet, which in the summer of 1874 could be seen by naked eye observation. On the basis of its brightness, the comet has been called the Great Comet of 1874; on July 13 the magnitude of the brightness was between 0 and 1.
C/1874 H1 | Introduction
Its apparent magnitude may have reached as high as -7, leading it to be classified among what are called the "Great Comets". This comet is noted especially for developing a 'fan' of six tails after reaching its perihelion.
Great Comet of 1744 | Introduction
The coma is the nebulous envelope around the nucleus of a comet, formed when the comet passes close to the Sun on its highly elliptical orbit; as the comet warms, parts of it sublimate. This gives a comet a "fuzzy" appearance when viewed in telescopes and distinguishes it from stars. The word "coma" comes from the Greek "kome" (κόμη), which means "hair" and is the origin of the word "comet" itself. The coma is generally made of ice and comet dust. Water composes up to 90% of the volatiles that outflow from the nucleus when the comet is within 3-4 AU of the Sun.
Coma (cometary) | Introduction
C/2001 OG108 (LONEOS) is a Halley-type comet with an orbital period of 48.51 years. It was discovered on 28 July 2001 by the LONEOS telescope at Lowell Observatory. Of the short-period comets with known diameters and perihelion inside the orbit of Earth, C/2001 OG108 is the second largest after Comet Swift–Tuttle. Observations taken in January and February 2002 showed that the "asteroid" had developed a small amount of cometary activity as it approached perihelion. It was subsequently reclassified as a comet. The comet came to perihelion (closest approach to the Sun) on 15 March 2002. It will come to aphelion in 2026 and the next perihelion passage is calculated to be on 6 June 2050.
C/2001 OG108 | Introduction
The Comet was an American science fiction fanzine, the first of its kind.
The Comet | Introduction