Comet Halley (1P/Halley) is a bright short-period comet that returns to the Sun every 75-76 years. It is the first comet for which an elliptical orbit was determined and the frequency of returns was established. Named after the English astronomer Edmund Halley. Associated with a comet meteor showers eta-Aquarids and Orionids. Although many brighter long-period comets appear each century, Halley's Comet is the only short-period comet clearly visible naked eye. Starting from the oldest observations recorded in historical sources China and Babylon, there were at least 30 appearances of the comet. The first reliably identifiable sighting of Halley's Comet dates back to 240 BC. e. The comet's last perihelion passage was in February 1986; the next one is expected in mid-2061. During its 1986 appearance, Halley's Comet became the first comet studied by spacecraft, including the Soviet Vega 1 and Vega 2 spacecraft, which provided data on the structure of the cometary nucleus and the mechanisms of formation of the comet's coma and tail.

Opening

Discoverer

Observed in ancient times; named after Edmund Halley, who discovered the periodicity of appearance

Date of discovery

1758 (first predicted perihelion)

Alternative designations

Halley's Comet, 1P

Orbital characteristics

Eccentricity (e)

Major shaft (a)

2.66795 billion km (17.83414 AU)

Perihelion (q)

87.661 million km (0.585978 AU)

Aphelion (Q)

5.24824 billion km (35.082302 AU)

Circulation period (P)

75.3a (Julian year)

Inclination (i)

Last perihelion

Next perihelion

physical characteristics

Dimensions

15x8 km, 11 km (average)

Weight

Density

600 kg/m3 (estimates range from 200 to 1500 kg/m3)

Albedo

Generated meteor showers

eta Aquarids, Orionids

Comet 1P/Halley

Comet discovery


Halley's Comet was the first comet with proven periodicity. European science until the Renaissance was dominated by the view of Aristotle, who believed that comets were disturbances in the Earth's atmosphere. However, both before and after Aristotle, many ancient philosophers expressed very insightful hypotheses about the nature of comets. Thus, according to Aristotle himself, Hippocrates of Chios (5th century BC) and his student Aeschylus believed that “the tail does not belong to the comet itself, but it sometimes acquires it, wandering in space, because our visual ray, reflected from the moisture carried behind the comet, it reaches the Sun. A comet, unlike other stars, appears at very large intervals of time, because, they say, it lags behind [the Sun] extremely slowly, so that when it appears again in the same place, it has already completed a full revolution.” In this statement one can see a statement about the cosmic nature of comets, the periodicity of its movement, and even the physical nature of the comet's tail, on which sunlight is scattered, and which, as modern research has shown, actually consists largely of gaseous water. Seneca (1st century AD) not only talks about the cosmic origin of comets, but also proposes a method of proving the periodicity of their movement, implemented by Halley: “It is necessary, however, that information be collected about all previous appearances of comets; for, owing to the rarity of their appearance, it is still impossible to ascertain their orbits; find out whether they follow the order and appear exactly on their day in a strict order.”

Aristotle's idea was refuted by Tycho Brahe, who used parallax observations of the 1577 comet (measurements of the comet's position taken in Denmark and Prague) to show that it was further from the Earth than the Moon. However, there was still uncertainty about whether comets orbited the Sun or simply followed straight paths through the Solar System.
In 1680-1681, 24-year-old Halley observed a bright comet (C/1680 V1, often called Newton's Comet), which first approached the Sun and then moved away from it, which contradicted the idea of straight motion. While exploring this issue, Halley realized that the centripetal force acting on a comet from the Sun should decrease in inverse proportion to the square of the distance. In 1682, the year of the next appearance of the comet, which was later named after him, Halley turned to Robert Hooke with a question - along what curve would a body move under the influence of such a force, but did not receive an answer, although Hooke hinted that he knew the answer. Halley went to Cambridge to see Isaac Newton, who immediately replied that, according to his calculations, the movement would occur along an ellipse. Newton continued to work on the problem of the motion of bodies under the influence of gravitational forces, refining and developing calculations, and at the end of 1684 he sent Halley his treatise “The Motion of Bodies in Orbit.” The delighted Halley reported on Newton's results at a meeting of the Royal Society of London on December 10, 1684 and asked Newton for permission to print the treatise. Newton agreed and promised to send a continuation. In 1686, at the request of Halley, Newton sent the first two parts of his extended treatise, called the Mathematical Principles of Natural Philosophy, to the Royal Society of London, where Hooke caused a scandal by declaring his priority, but was not supported by his colleagues. In 1687, with Halley's money, Newton's most famous treatise was printed in an edition of 120 copies. Thus, interest in comets laid the foundations of modern mathematical physics. In his classic treatise, Newton formulated the laws of gravity and motion. However, his work on the theory of cometary motion was not yet completed. Although he suspected that the two comets observed in 1680 and 1681 (and which aroused Halley's interest) were in fact one comet before and after passing close to the Sun, he was unable to fully describe its motion within his model. This was achieved by his friend and publisher Halley, who, in his 1705 work “Review of Cometary Astronomy,” used Newton’s laws to take into account the gravitational influence on the comets of Jupiter and Saturn.

After studying historical records, Halley compiled the first catalog of the orbital elements of comets and drew attention to the coincidence of the paths of comets 1531 (observed by Apian), 1607 (observed by Kepler) and 1682. (which he observed himself), and suggested that this is the same comet, revolving around the Sun with a period of 75-76 years. Based on the detected period and taking into account rough approximations of the impact major planets, he predicted the return of this comet in 1758.
Halley's prediction was confirmed, although the comet could not be discovered until December 25, 1758, when it was noticed by a German peasant and amateur astronomer I. Palich. The comet did not pass through perihelion until March 13, 1759, because disturbances caused by the attraction of Jupiter and Saturn led to a delay of 618 days. Two months before the reappearance of the comet, this delay was pre-calculated by A. Clairaut, who was assisted in the calculations by J. Lalande and Madame N.-R. Babble. The calculation error was only 31 days. Halley did not live to see the comet return; he died in 1742. Confirmation of the return of comets was the first demonstration that not only planets can orbit the Sun. This was the first successful confirmation of Newton's celestial mechanics and a clear demonstration of its predictive power. The comet was first named in honor of Halley by the French astronomer N. Lacaille in 1759.

Orbit parameters


The orbital period of Halley's Comet over the past three centuries ranged from 75 to 76 years, but for the entire period of observation from 240 BC. e. it varied over a wider range - from 74 to 79 years. Variations in period and orbital elements are associated with the gravitational influence of the major planets that the comet passes by. The comet revolves in a highly elongated elliptical orbit with an eccentricity of 0.967 (0 corresponds to a perfect circle, 1 to movement along a parabolic trajectory). At its last return, it had a distance to the Sun at perihelion of 0.587 AU. e. (between Mercury and Venus) and the distance at aphelion is more than 35 a. e. (almost like Pluto). The comet's orbit is inclined to the ecliptic plane by 162.5° (that is, unlike most bodies in the solar system, it moves in the direction opposite to the movement of the planets and is inclined to the Earth's orbit by 180-162.5 = 17.5°). The comet's perihelion is elevated above the ecliptic plane by 0.17 AU. e. Due to the large eccentricity of the orbit, the speed of Halley's comet relative to the Earth is one of the highest among all bodies in the Solar System. In 1910, when flying past our planet, it was 70.56 km/s. As the comet's orbit approaches Earth's orbit at two points, the dust generated by Halley's Comet forms two meteor showers visible on Earth: the Eta Aquarids in early May and the Orionids in late October.
Halley's Comet is classified as a periodic or short-period comet, that is, one whose orbital period is less than 200 years. Comets with an orbital period of more than 200 years are called long-period. Short-period comets generally have a low orbital inclination to the ecliptic (about 10 degrees) and an orbital period of about 10 years, so the orbit of Halley's comet is somewhat atypical. Short-period comets with orbital periods of less than 20 years and orbital inclinations of 20-30 degrees or less are called the Jupiter family of comets. Comets with an orbital period, like Halley's comet, ranging from 20 to 200 years and an orbital inclination ranging from zero to more than 90 degrees are called Halley-type comets. To date, only 54 Halley-type comets are known, while the number of identified Jupiter-type comets is about 400.
It is assumed that Halley-type comets were originally long-period comets, whose orbits changed under the influence of the gravitational attraction of the giant planets. If Halley's Comet was previously a long-period comet, then it most likely originates from the Oort cloud - a sphere consisting of cometary bodies, surrounding the Sun at a distance of 20,000-50,000 a. e. At the same time, Jupiter's family of comets is believed to originate from the Kuiper belt - a flat disk of small bodies at a distance from the Sun between 30 AU. e. (orbit of Neptune) and 50 a. e. Another point of view on the origin of Halley-type comets was also proposed. In 2008, a new trans-Neptunian object was discovered with a retrograde orbit similar to that of Halley's Comet, which was designated 2008 KV42. Its perihelion is located at a distance of 20 AU. e. from the Sun (corresponds to the distance to Uranus), aphelion - at a distance of 70 a. e. (exceeds twice the distance to Neptune). This object may be a member of a new family of small bodies solar system, which can serve as a source of Halley-type comets.

The results of numerical simulations indicate that Halley's Comet has been in its current orbit for 16,000 to 200,000 years, although accurate numerical integration of the orbit is impossible due to the appearance of instabilities associated with planetary disturbances over intervals of more than a few tens of revolutions. The comet's motion is also significantly influenced by non-gravitational effects, since when approaching the Sun it emits jets of gas that sublimate from the surface, leading to reactive recoil and a change in orbit. These orbital changes can cause variations in perihelion transit times of up to four days.
In 1989, Chirikov and Vecheslavov, having analyzed the results of calculations of 46 appearances of Halley's comet, showed that on large time scales the dynamics of the comet are chaotic and unpredictable. Moreover, on time scales of the order of hundreds of thousands and millions of years, the behavior of the comet can be described within the framework of the theory of dynamic chaos. The same approach allows us to obtain simple approximate estimates of the time of the closest passages of the comet through perihelion.
The estimated lifetime of Halley's Comet could be on the order of 10 million years. Recent studies show that it will evaporate or break into two in a few tens of thousands of years, or will be thrown out of the solar system in a few hundred thousand years. Over the past 2000-3000 returns, the nucleus of Halley's comet has decreased in mass by 80-90%.

Observation history


The first reliable observation of a comet dates back to 240 BC. BC, but the first predicted appearance of a comet was only in 1759 AD.

1759- First predicted appearance of Halley's Comet. The comet passed through perihelion on March 13, 1759, 32 days later than A. Clairaut’s prediction. It was discovered on Christmas Day 1758 by amateur astronomer I. Palich. The comet was observed until mid-February 1759 in the evening, then disappeared against the background of the Sun, and from April it became visible in the pre-dawn sky. The comet reached approximately zero magnitude and had a tail extending 25°. It was visible to the naked eye until early June. The last astronomical observations of the comet were made at the end of June.
1835- Since not only the date of passage of Halley’s comet perihelion was predicted for this appearance, but also the ephemeris was calculated, astronomers began searching for the comet using telescopes in December 1834. Halley's comet was discovered as a weak point on August 6, 1835 by the director of a small observatory in Rome, S. Dumouchel. On August 20 in Dorpat it was rediscovered by V. Ya. Struve, who two days later was able to observe the comet with the naked eye. In October, the comet reached 1st magnitude and had a tail extending about 20°. V. Ya. Struve in Dorpat with the help of a large refractor and J. Herschel on an expedition to the cape Good Hope made many sketches of the comet, which constantly changed its appearance. Bessel, who also monitored the comet, concluded that its movement was significantly influenced by the non-gravitational reactive forces of gases evaporating from the surface. On September 17, V. Ya. Struve observed the occultation of a star by the head of a comet. Since no change in the star’s brightness was recorded, this allowed us to conclude that the substance of the head was extremely rarefied and its central core was extremely small. The comet passed perihelion on November 16, 1835, just a day later than the prediction of F. Ponteculane, which allowed him to clarify the mass of Jupiter, taking it equal to 1/1049 of the mass of the Sun ( modern meaning 1/1047.6). J. Herschel followed the comet until May 19, 1836. Halley's Comet in 1910
1910- During this appearance, Halley's Comet was photographed for the first time and spectral data on its composition were obtained for the first time. The minimum distance from the Earth was only 0.15 AU. e., and the comet was a bright celestial phenomenon. The comet was discovered on approach on September 11, 1909 on a photographic plate by M. Wolf in Heidelberg using a 72-cm reflecting telescope equipped with a camera, in the form of an object of 16-17 magnitude (the shutter speed when photographing was 1 hour). An even weaker image was later found on a photographic plate obtained on August 28. The comet passed perihelion on April 20 (3 days later than predicted by F.H. Cowell and E.C.D. Crommelyn) and was a bright spectacle in the predawn sky in early May. At this time, Venus passed through the comet's tail. On May 18, the comet found itself exactly between the Sun and the Earth, which also plunged into the comet's tail, which is always directed away from the Sun, for several hours. On the same day, May 18, the comet passed across the disk of the Sun. Observations in Moscow were carried out by V.K. Tserasky and P.K. Sternberg using a refractor with a resolution of 0.2-0.3 "", but were unable to distinguish the nuclei. Since the comet was at a distance of 23 million km, this made it possible to estimate that its size was less than 20-30 km. The same result was obtained from observations in Athens. The correctness of this estimate (the maximum size of the core turned out to be about 15 km) was confirmed during the next appearance, when the core was studied with close range using spacecraft. At the end of May - beginning of June 1910, the comet had 1st magnitude, and its tail had a length of about 30°. After May 20, it began to move away quickly, but was photographically recorded until June 16, 1911 (at a distance of 5.4 AU).

In the course of numerous studies, about 500 photographs of the head and tail of the comet, about 100 spectrograms were obtained. It was also carried out big number determinations of the position of the comet, clarifying its orbit, which had great importance while planning the spacecraft exploration program ahead of the next appearance in 1986. Based on studies of the outlines of the comet's head using long-focus astrographs, S. V. Orlov constructed a theory of the formation of the comet's head.

Spectral analysis of the comet's tail showed that it contains poisonous cyanogen gas and carbon monoxide. With the Earth set to pass through the comet's tail on May 18, the discovery sparked doomsday predictions, panic, and a rush to buy quack "anti-comet pills" and "anti-comet umbrellas." In fact, as many astronomers hastened to point out, the comet's tail is so rarefied that it cannot have any effect. negative effects on earth's atmosphere. On May 18 and the following days, various observations and studies of the atmosphere were organized, but no effects that could be associated with the action of the cometary substance were detected.

The famous American humorist Mark Twain wrote in his autobiography in 1909: “I was born in 1835 along with Halley’s comet. She will appear again next year and I think we will disappear together. If I don't disappear with Halley's Comet, it will be the greatest disappointment of my life. God probably decided: these are two bizarre inexplicable phenomena, they arose together, let them disappear together.” And so it happened: he was born on November 30, 1835, two weeks after the comet passed perihelion, and died on April 21, 1910, the day after the next perihelion.

Events

Small Comet Hartley 2 will be visible from Earth with the naked eye on October 20, when it will fly past the planet just 11 million kilometers away. In recent centuries, this will be the closest “contact” of our planet with a comet.

Hartley 2 was discovered in 1986. Its orbital path was far from Earth until a couple of rotations around Jupiter brought the orbit closer.

Hartley 2 will be among the comets that have flown past last centuries close enough to Earth.

Comet McNaught lit up the sky in 2007. The brightest comet in over forty years, McNaught was named the Great Comet of 2007. Astronauts were able to observe this comet, thereby shedding light on the composition of such celestial bodies. The Willis spacecraft discovered a decrease here solar wind.

The comet's discoverer, Australian astronomer Robert McNaught, discovered another new bright comet in 2009 McNaught S/2009 R1 , which flew past the Earth in June of this year.

Comet Schwassman-Wachmann surprised scientists in 1995 when it split into three mini-comets. Decay celestial body By the way, it is still going on. By the time it approached Earth in 2006, Schwassman-Wachmann had already split into 30 small pieces, some of which will make their closest approach to Earth in 2022.

Hale-Bopp It is considered the longest-lasting comet of the 20th century. Earthlings could observe it for 18 months from 1996 to 1997.

The giant comet was first seen beyond the orbit of Jupiter and shone a thousand times brighter than Halley's Comet, located at the same distance. NASA experts estimate the diameter of Hale-Bopp's core to be 19 to 25 miles, which is two and five times the size of the comet that struck our planet 65 million years ago. Hale-Bopp will not return to our solar system until 4385.

"Great Comet of 1996" Hyakutake , flying close to the Earth, illuminated the sky with a bluish-green light, according to scientists, due to the presence of diatomic carbon in the emission. Hyakutake was also the first comet to emit X-rays.



Shoemaker-Levy-9 collided with Jupiter in 1994. Then we observed for the first time the collision of two bodies in the solar system. As a result of such a “meeting,” gas bubbles formed and dark traces remained in the atmosphere.

Shoemaker-Levy -9 became the first comet to orbit a planet rather than the Sun. Jupiter most likely pulled the comet into its orbit in the 1960s and 70s.

Astronomers predicted a collision of the Earth with the Earth in 2126. Comet Swift-Tuttle . However, they subsequently revised their calculations - the comet will fly past us at a distance of 15 million miles.

This comet is part of the Perseid meteor shower, which appears annually in the summer night sky.

The most famous comet is probably Comet Halley , visible from Earth every 75 or 76 years. Thus, a person can observe it, say, twice in his life.



The comet has been observed since ancient times. But the fact that this is exactly the comet cyclically observed from Earth was discovered in 1705 by the English astronomer Edmond Halley.

The next time the comet will be visible from Earth will be in 2061.

The closest thing to our planet in the last two centuries is a small comet IRAS-Araki-Alcock in 1983. The size of a moon, it appeared in the sky just three million miles away. Specialists from NASA were able to prove with the help of a satellite that the component of this comet contains sulfur - the first discovery of its kind.

The brightest comet of the century was West in 1976. It was so clear that it could be observed during the daytime. This comet will still not soon return to a distance close to Earth.

Halley's Comet is undoubtedly the most popular of the comets. With amazing consistency, approximately every 76 years it appears nearby, and every time for 22 centuries, earthlings have recorded this rare event. Let us clarify that the comet's orbital period varies from 74 to 79 years, so 76 years - middle period over the past centuries.

Not all appearances of Halley's comet in the earth's sky were remarkable. Sometimes, however, the brilliance of its core exceeded the brilliance of Venus during the period of the planet’s best visibility. In such cases, the comet's tails became long and spectacular, and the records in the annals reflected the excitement of observers caused by the "ominous" tailed star. In other years, the comet looked like a dim, foggy star with a small tail, and then the entries in the chronicles were very brief.

Over the past 2000 years, Halley's Comet has never approached Earth closer than 6 million km. Approach to Earth in 1986 was the most unfavorable in the entire history of observations of the comet - the conditions for its visibility from Earth were the worst.

For those who have never seen a real comet, but judge the appearance of comets from drawings in books, let us inform you that the surface brightness of comet tails never exceeds the brightness Milky Way. Therefore, in the conditions of any major modern city a comet is no easier to see than the Milky Way. At best, it is possible to view its core in the form of a more or less bright, slightly hazy and somewhat “smeared” star. But where the sky is clear, its background is black, and the scattering of stars of the Milky Way is clearly visible, big comet with bright tails is, of course, an unforgettable sight.

Not all people are able to see the passage of Comet Halley near the Earth twice in their lives. Still, 76 years is a long period, close to the average duration of human life, and therefore the list of famous people who twice observed the return of Halley’s comet is not so long.

Among them we find Johann Halle (1812-1910) - the astronomer who discovered the planet Neptune according to the predictions of W., Caroline Herschel (1750 -1848) - the sister of the famous founder stellar astronomy, Leo Tolstoy (1828-1910) and others. It is curious that the famous American writer Mark Twain was born two weeks after the appearance of Halley's Comet in 1835, and died the day after its next closest approach to the Sun in 1910. Not long before this, Mark Twain jokingly told his friends that since he was born in the year of the next appearance of Halley's Comet, he would die immediately after its next return!

It is interesting to trace how the Earth greeted the famous comet throughout the history of its observations. Only in 1682 They suspected that they were dealing with a periodic comet. In 1759 this suspicion was confirmed. But this year, as well as the next visit of the comet in 1835, astronomers were only able to conduct telescopic observations of this cosmic body, which said little about its physical nature. Only in 1910 Scientists met Halley's Comet fully armed. The comet flew near the Earth, touching it (in May 1910) with its tail. It was very convenient to observe it from Earth, and photography, spectroscopy and photometry were already in the arsenal of astronomers.

By that time, the great Russian comet explorer Fyodor Aleksandrovich (1831-1904) had created a mechanical theory of cometary forms, and his followers were able to successfully apply new theory to the interpretation of observed cometary phenomena. In general, the previous meeting with Halley's comet in 1910. can be called a holiday of cometary astronomy. At this time the foundations of modern physical theory comets, and it would not be an exaggeration to say that current ideas about comets owe much to the successes of 1910.

Comet Halley made its thirtieth return to the Sun in 1986. received an unusual reception. For the first time, spacecraft flew to the comet in order to explore it in close proximity. Soviet scientists, led by academician R.Z. Sagdeev, developed and implemented the Vega project - sending special interplanetary stations Vega-1 and Vega-2 to the comet. Their task was to photograph the nucleus of Halley's comet from close range and study the processes occurring in it. The European project “Giotto” and the Japanese projects “Planet-A” and “Planet-B” were also part of the international research program for Halley’s Comet, which began to be developed back in 1979.

Now it is pleasant to state that this program has been successfully completed, and during its implementation, fruitful international cooperation of scientists has emerged different countries. For example, during the implementation of the Giotto program, American specialists helped restore normal communication with the station, and later Soviet scientists ensured its flight at a given distance from the cometary nucleus.

Astronomical tracking stations brought considerable benefit in receiving information from stations flying near Halley's comet. Now, with our common efforts, we can imagine what Halley’s comet is and, therefore, what comets in general are like. The main part of the comet - its nucleus - is an elongated body irregular shape with dimensions 14x7.5x7.5 km. It rotates around its axis with a period of about 53 hours. This is a huge block of contaminated ice, which contains small solid particles of silicate nature as “contaminants”.

Recently, for the first time in the press, a comparison of the nucleus of Halley's comet with a dirty March snowdrift appeared in the press, in which a mud crust protects the snowdrift from rapid evaporation. Something similar happens in a comet - under the influence sun rays the ice component sublimes and, in the form of gas streams, moves away from the core, which very weakly attracts all objects to itself. These gas flows also carry along solid dust, which forms the comet's dust tails.

The Vega-1 apparatus established that every second 5 - 10 tons of dust are ejected from the core - some of it still remains, covering the ice core with a protective dust crust; Because of this crust, the reflectivity (albedo) of the core is noticeably reduced and the surface temperature of the core turns out to be quite high. Water constantly evaporates from a comet near the Sun, which can explain the presence of a hydrogen corona in comets. In general, the “ice model” of the core was brilliantly confirmed, and from now on it has become a fact instead of a hypothesis. The size of Halley's comet is so small that its nucleus could easily fit on the territory of Moscow inside the ring road. Once again, humanity has become convinced that comets are small bodies in a state of continuous destruction.

Meeting in 1986 was very successful for science, and now we will meet Halley’s comet only in 2061.

The life of comets is relatively short - even the largest of them can make only a few thousand revolutions around the Sun. After this period, the comet's nucleus completely disintegrates. But such decay occurs gradually, and therefore, throughout the life of the comet, a trail of decay products of its nucleus, resembling a donut, is formed along the entire orbit. That is why, every time you encounter such a “donut”, it flies into the earth’s atmosphere. a large number of"shooting stars" - meteoroids created by a disintegrating comet. Then they talk about the meeting of our planet with a meteor shower.

Twice a year, in May and October, the Earth passes through a “meteor donut” generated by the nucleus of Comet Halley. In May, meteors fly out from the constellation Aquarius, in October - from the constellation Orion.

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> Halley

Comet Halley, captured in 1986

– comet of the Solar System: period of revolution, photo, history of research, year of Halley’s comet, eccentricity, when it arrives, semimajor axis.

Halley's Comet is a short-period comet that arrives at our planet every 75 years. Last time we saw her in 1986. If you're wondering when it will arrive back, Earth expects it to return in 2061.

The comet was named after Edmund Halley, who investigated its arrivals in 1531, 1607 and 1682. He realized that all three comets were the only returning object. So he was able to predict that 1758 should be perceived as the year of Halley's Comet.

Halley did not live to see this moment, but his conclusions turned out to be correct. Moreover, his calculations showed that a certain category of comets constantly returns to Earth. In 1986, telescopes on Earth monitored the arrival of Halley's Comet, and some spaceships they even planned to take samples.

It is difficult to observe because the period of Halley's Comet spans decades. Therefore, scientists focus on other objects to compare and infer class characteristics. For example, the analysis of 67P/Churyumov-Gerasimenko showed that the composition of water on comets differs from that on Earth.

History of Halley's Comet

The first record of a comet was left in 239 BC. e. Listed in the Chinese chronicles of Shin Shi and Wen Xiang Tong Khao. The ancient Greeks left a record in 466 BC. e. The return was recorded in Babylon in 164 and 87. BC. These texts are important because they allow us to study its orbital path in the past.

The arrival in 1301 inspired the artist Giotto to paint The Star of Bethlehem, which tells the story of the victory of William the Conqueror. At that time, scientists thought that each event indicated the arrival of a new object. They were often seen as harbingers of disasters. This is also noticeable in Shakespeare's play Julius Caesar, where one of the lines says that comets mark the death of kings.

Detection of the periodicity of Comet Halley

Even during Shakespeare's lifetime, astronomers were inclined to believe that the Sun stood at the center of the solar system. Many years passed until a whole powerful concept was established that forces us to take a fresh look at our place in the Universe (the heliocentric system).

In 1705, Edmund Halley completed his study of 24 comets and published An Astronomical Summary of Comets, which noted the objects that arrived in 1337-1698. Three of them coincided in orbits and other parameters, and he assumed that they were all a single object. He also calculated that her arrival should be expected in 1758.

The comet arrived on time and was followed by inspired scientists from all over the world. Halley's Comet is shown in the photo below.

The comet's return in 1910 was especially impressive because it came within 22.4 million km of us. It was this year that we received her first photo. It's amazing that Mark Twain accurately predicted his death. He wrote that he arrived with the comet in 1835 and would leave with the next arrival. This happened on April 21, 1910.

Space Age

In 1986, humanity was able to use spaceships for the first time in research. And it was a good moment, because it came close to the planet. Several devices called “Halley's Armada” were sent to the comet. The Soviet-French mission Vega 1 and 2 went to the object and one even managed to image the core. Two probes also flew from Japan.

Photos of Halley's comet have also been received from NASA's International Cometary Explorer, which has been operating since 1978. The photographs were taken at a distance of 28 million km.

The arrival of the comet also marked a tragic event. The crew of the Challenger STS-51L planned to monitor her. But on January 28, the ship exploded during takeoff and 7 astronauts died.

The re-arrival is still decades away, but we can keep track of cosmic remnants in space. We are talking about the Orionid meteor shower in October.

In 2061, Halley's Comet will be on the same side of the Sun as Earth and will be much brighter. Scientists believe its periodicity is still questionable because a collision with any object would push it back for thousands of years.

Its brightness is predicted to reach an apparent value of -0.3. There are also objects included in the “Halley family of comets.” They converge in orbital characteristics. But there are also inconsistencies, which means they may have a different origin. Perhaps they are members of the Oort cloud or created from the centaurs (between Jupiter and the Kuiper belt).

Scientists are not sitting idle while waiting for the comet. In 2014-2016 We had the amazing opportunity to visit comet 67P/Churyumov-Gerasimenko and analyze samples. In the same way, the researchers studied 81P/Wilda and 9P/Tempel.

Photos of Halley's Comet

Halley's Comet in 1986

Comet as seen at Table Mountain Observatory

On January 13, 1986, James Young photographed Halley's Comet from Table Mountain Observatory using a 24-inch reflecting telescope. The stripes created in the exhibition are stars in the territory of Aquarius. The image highlights the coma and the charged ion tail stretching over 725,000 km.

Comet in 1910

Comet reviewed by Giotto

On March 13, 1986, the multicolor camera of the Giotto spacecraft recorded a cometary nucleus at a distance of 600 km.

Halley's Comet in Diamond Mountain Review

Halley's Comet May Be Captured

Halley's Comet in Mount Wilson Survey

Discoverer: Observed in ancient times;
named after Edmund Halley, who discovered the periodicity of appearance
Opening date: 1758 (first predicted perihelion)
Alternative designations:
Orbit characteristics
Eccentricity 0,9671429
Major axle shaft 2.66795 billion km
(17.83414 AU)
Perihelion 87.661 million km
(0.585978 au)
Aphelion 5.24824 billion km
(35.082302 a.u.)
Circulation period 75.3 g
Orbital inclination: 162.3°
Last perihelion: February 9, 1986
Next perihelion: July 28, 2061
physical characteristics
Dimensions: 15×8 km, 11 km (average)
Weight: 2.2 10 14 kg
Average Density: 600 kg/m³ (estimates range from 200 to 1500 kg/m³)
Albedo: 0,04
Generated meteor showers eta Aquarids, Orionids

HALLEY'S COMET the only short-period comet (orbital period approx. 76 years), easily accessible to observation with the naked eye.

Relatively small comet nuclei, consisting of ice interspersed with dust particles, approaching the Sun, are enveloped in a huge atmosphere (coma) of gas and dust hundreds of thousands of kilometers long. Intense solar heating evaporates ice from the comet's nucleus, releasing gas and dust into the surrounding atmosphere. Then, under the pressure of solar photons and high-speed particles of the solar wind, this substance flies away in the direction opposite to the Sun, forming a gas-dust tail of a comet, reaching a length of millions of kilometers.

In March 1986, Halley's Comet was observed not only by numerous amateur astronomers and professional scientists, but also by five international spacecraft ( see also SPACE PROBE). The Japanese probes Sakigake and Suisei observed a huge hydrogen cloud surrounding the comet and studied the interaction of the comet with charged particles of the solar wind. The Soviet probes Vega-1 and 2 passed on March 6 and 9 at distances of 8,871 and 8,014 km from the comet. The European Space Agency's Giotto probe passed on March 14, 1986 closest to the comet's nucleus, only 605 km. Television images transmitted by European and Soviet probes showed the comet's pitch-black core. By comparing ground-based and space-based observations of the gas and dust surrounding the core, scientists concluded that it is about 50% ice, with the rest being dust and other non-volatile substances. Ice consists mainly of water (80%) and carbon monoxide (10%), with the rest being formaldehyde, carbon dioxide, methane, ammonia and hydrocyanic acid. The non-volatile part, mainly represented by micron-sized dust particles, consists of either rocky matter or light hydrocarbons.

Externally, the nucleus of Comet Halley appears as a potato-shaped object measuring approx. 14ґ 10ґ 8 km. Its very black crust of carbonaceous (organic) matter is covered in many places with fractures, through which the subcrustal substance is visible, consisting mainly of water ice interspersed with dark dust particles. Since the comet's nucleus rotates around its axis with a period of several days, this ice is influenced sunlight evaporates and turns into gas, which, flying out of the core, takes dust particles with it. It was this nucleus, like a small dirty iceberg, that supplied all the gas and dust that formed the vast atmosphere and tail of the comet.

Halley's Comet was the first to be predicted to periodically return to the central region of the Solar System. Using the mathematical apparatus developed by I. Newton, his colleague E. Halley (1656-1742) calculated the parameters of the orbits of 24 comets observed by astronomers in previous years. It turned out that the comets that appeared in 1531, 1607 and 1682 had similar orbits. Halley suggested that they were in fact the same object, and predicted that the comet that now bears his name would return to the Sun at the end of 1758 or at the beginning of 1759. When the German amateur astronomer I. Palich discovered the comet in the sky at the end of 1758, this became a triumph of Halley's calculations and Newton's laws underlying them.

On its long path along the orbit, Halley's comet is subject to the gravitational attraction of the planets it passes by, and as it approaches the Sun, it feels a weak force response from the gases evaporating from the surface of its core. Under the influence of these disturbances, the orbital period of a comet can change for several years from one appearance to another. Calculating the past movement of Halley's Comet allows us to calculate each of its 30 appearances between 240 BC. and 1986. Its next two passages near the Sun are expected on July 28, 2061 and March 27, 2134. The comet's passage in 1986 slightly disappointed observers, since it did not come close enough to the Earth. Its minimum distance from our planet on April 10, 1986 was 63 million km. Unfortunately, during its return in 2061, the comet will not come closer than 71 million km to Earth. This will happen on July 29, 2061. And the return of 2134 will be more impressive, since the comet on May 7, 2134 will be at a distance of 13.7 million km from Earth.