Halley's comet is undoubtedly the most popular of the comets. With amazing constancy approximately every 76 years, it appears near the Earth, and every time for 22 centuries, earthlings have been registering these rare events. Let us clarify that the period of revolution of a comet around the Sun varies from 74 to 79 years, so 76 years is the average period for the past centuries.

Historical records, unknown to Edmond Halley, show that the comet's previous appearances stretched far into the past, long before comets were recognized as periodic. Chasing a comet's orbit over time is not as easy as it might sound, because the gravitational effects of the planets are constantly tugging at the comet and changing its orbit. If the comet's orbit is slightly expanded by the attraction of the planets, it will take longer; if the orbit shrinks, the comet will return sooner.

Their records are an encyclopedic source of information about ancient events in the sky. The tail was unbranched and it pointed north. The Emperor summoned the "Astronomer Royale" and asked him about the reason for these stellar changes. I hope Astronomer Royal was helpful because the tradition was that two Chinese astronomers who were caught taking a nap by an unexpected eclipse were beheaded.

Not all appearances of Halley's comet in the earth's sky were remarkable. Sometimes, however, the brightness of its core exceeded the brightness of Venus during the period of the best visibility of the planet. In such cases, the comet's tails became long, 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, hazy star with a small tail, and then the records in the chronicles were very short.

This was annoying for Yeoman and Qiang, who needed to check their calculations over the years. But the confirmation came from a different direction: the Babylonians, the inhabitants of the Middle East, who diligently collected diaries of astronomical information. Perhaps even old records of the comet, still unnoticed, lie on Babylonian clay tablets kept in the British Museum.

Its depiction on the Bayeux Tapestry, pointing to King Harold by his troubled aides, is perhaps the most famous example of a comet in history. According to the accompanying text of the Chronicle, the appearance of the comet was accompanied by three months of rain and storms, culminating in a plague.

Over the past 2000 years, Halley's Comet has never approached the Earth closer than 6 million km. Approach to the 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, we will inform you that the surface brightness of comet tails never exceeds the brightness Milky Way. Therefore, in the context of any large modern city a comet is no easier to see than the Milky Way. At best, it is possible to consider its core in the form of a more or less bright, slightly foggy and somewhat “smeared” star. But where the sky is clear, its background is black, and a scattering of stars of the Milky Way is clearly visible, a large comet with bright tails is, of course, an unforgettable sight.

John Tebbutt was perhaps the most important Australian astronomer of the year. He had previously turned down a position as government astronomer in Sydney a year earlier. Tebbutt, who wrote about 400 specialized papers, remained a lifelong amateur astronomer. On the contrary, it seemed like a false alarm, as the object did not change its position in the following days. June, he introduced himself to the observers in southern hemisphere with a 40 degree tail. Therefore, it could not be seen close to the Earth near the northern hemisphere.

No one suspected anything about the star, because the news spread at that time due to the lack of telegraph communication in the speed of the ships. As it darkened that summer evening, a star of unspeakable size in the sky came out of nowhere. Its brightness was so great that it cast shadows.

Not all people manage to see the passage of Halley's comet near the Earth twice in their lives. Still, 76 years is a long period, close to the average duration 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 Galle (1812-1910) - an astronomer who discovered the planet Neptune on the instructions of W. Le Verrier, Caroline Herschel (1750 -1848) - the sister of the famous founder of stellar astronomy William Herschel, 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. Shortly 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 her next return!

I saw June and held on to the rising moon. Due to its favorable position on the railroad and the short distance to Earth, Comet Tebutt presented itself for several days with extremely bright colors. and extended tail. The unrealistic size and enormous brightness were due to both the small distance and the strong scattering of sunlight on cometary dust. That night, the tail probably covered the entire sky. Strange phenomena of scattered light are reported all over the world, John Tebbutt reports a whitish light that came from the entire firmament, but especially from the eastern horizon.

It is instructive to trace how the Earth met the famous comet throughout the history of its observations. Only in 1682. astronomers 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 able to make only 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, hitting it (in May 1910) with its tail. It was very convenient to observe it from the Earth, and photography, spectroscopy and photometry were already in service with astronomers. By that time, the great Russian explorer of comets, Fyodor Alexandrovich Bredikhin (1831-1904), had created a mechanical theory of cometary forms, and his followers were able to successfully apply the new theory to the interpretation of observed cometary phenomena. In general, the previous meeting with Halley's comet in 1910. can be called a celebration of cometary astronomy. At this time, the foundations of the modern physical theory of comets were laid, and it would not be an exaggeration to say that the current ideas about comets are largely due to the successes of 1910.

Observers in the northern hemisphere looked along the synchronous tail from the back to the coma, which appeared in a telescope richly structured with jets and "envelopes". After the ground left the tail after about 2 days, the brightness and length of the tail rapidly decreased.

However, superstitious natures later pointed to Tebbutt's Comet as the forerunner of the American civil war.


  • Schreiber, Esslingen.
  • Worm, Karl: comets. 160 pp. Springer-Verlag, Berlin, Göttingen, Heidelberg.
This is one of the most famous and bright comets of "short" periodicity.

On its thirtieth return to the Sun, Halley's comet was in 1986. met unusually. First flew to a comet spacecraft to explore it up close. Soviet scientists headed 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 included photographing the nucleus of Halley's comet at close range and studying the processes occurring in it. The European project "Giotto" and the Japanese projects "Planet-A" and "Planet-B" were also included in the international program of research on Halley's comet, which began to be developed as early as 1979. Now it is pleasant to state that this program has been successfully completed, moreover, in the course of its implementation showed fruitful international cooperation of scientists different countries. So, 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 were of considerable use in receiving information from stations flying near Halley's comet. Now, by joint efforts, we can imagine what Halley's comet is and what, therefore, comets are in general. The main part of the comet - its nucleus - is an elongated body of irregular shape with dimensions of 14x7.5x7.5 km. It rotates around its axis with a period of about 53 hours. This is a huge block of polluted ice, where fine solid particles of a silicate nature are included as "pollutions". Recently in the press for the first time appeared a comparison of the nucleus of Halley's comet with a dirty March snowdrift, in which the mud crust protects the snowdrift from rapid evaporation. Something of this kind also occurs in a comet - under the action of the sun's rays, the ice component is sublimated and in the form of gas flows away from the nucleus, which very weakly attracts all objects to itself. These streams of gases also carry away solid dust, which forms the dust tails of the comet.

Halley's Comet was the first to be recognized by the magazine, its orbit was first calculated by astronomer Edmund Halley, previously observed by the German astronomer Regiomontano. There are reports that this comet was first seen in 239 BC. Halley concluded that they corresponded to the same celestial object that returned every 76 years. His prediction was not entirely correct, as the comet returned on December 25th.

The orbit of this comet meets in the opposite direction from the planet. Spaceship Giotto provided astronomers with the first insight into the surface structure of Halley's comet. Its tail extends millions of kilometers through space, and its core is relatively small: it is 15 km long, 8 km wide and 8 km high. Only 4% of the light this comet receives is reflected, and although it looks very bright and white, it is black. White color, which we see on Earth, is associated with the separation of steam from the nucleus of a comet.

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

Halley's Comet in the Middle Ages

Vapors are composed of 80% water, 17% carbon monoxide, 3 to 4% carbon dioxide and trace hydrocarbons. It was also found that the comet's nucleus contains empty craters and some full of ice. Contrary to claims that they were two different comets, English astronomer John Flamsteed proposed the single star hypothesis. Twenty-seven years after Halley's death, his prediction was fulfilled. The verification of this prediction was the final consecration of the theory of gravity and Newtonian mechanics. Since then, the comet will be called "Halley".

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

The life of comets is relatively short - even the largest of them is able to complete only a few thousand revolutions around the Sun. After this period, the comet's nucleus completely disintegrates. But such a decay occurs gradually, and therefore, during the life of a comet, a plume is formed along the entire orbit from the decay products of its nucleus, resembling a donut. That is why every time when meeting with such a "donut" a large number of "shooting stars" flies into the earth's atmosphere - meteor bodies generated by a decaying comet. Then they talk about the meeting of our planet with a meteor shower.

As the time for Halley to become visible approached, the public became intensely interested in the star, which was reflected in various newspaper articles about it and commercial advertisements that echoed their arrival. The image quality was not good, so it was little used. Camera target today at the Observatory Astronomical Museum. Perrin using a 30 cm refractor when it is described as weak, with a small comma in which there was a pronounced central condensation. Astronomer Enrique Chaudet "recovered" after seeing him again on April 12 after a long wait.

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


History of comets.

In February and March 1744, a great revival reigned in the circles of scientists of the St. Petersburg Academy of Sciences. These days a remarkably bright comet with a huge tail was observed in the sky. The then young scientist M. V. Lomonosov followed the comet with particular interest, its movement among the stars and the change in its appearance. This comet presented an exceptional spectacle: its foggy "appendage" stretched almost half the sky and consisted, as it were, of several separate tails.

Fortunato Devoto, Interim Director of the Observatory of this city. This observation was made from the bishop's palace because the tall trees that surrounded the observatory interfered with it. In mid-May, the comet, when it reached its largest size, acquired magnificent proportions.

Calculations of past and future appearances of Halley's comet

During most of May, the comet was my wonderful sight. Two weeks before its closest approach to Earth was in full swing, and its appearance was scary enough to raise suspicious fears for those who did not know the true nature of the phenomenon.

Most comets have highly elliptical orbits and spend most of their time in the outer solar system, coming close to the Sun only for a short time. The distinction between comets and asteroids is somewhat controversial. The main difference seems to be that comets have more elongated orbits. For a long time, people knew nothing about the nature of comets. Their appearance was so sudden and mysterious, and the appearance was so unusual, that superstitious people saw in them the harbingers of all sorts of troubles and misfortunes; wars, plagues, cholera, famines.

With its gigantic tail that covered from the horizon to the zenith, where the bifurcation was clearly visible for several days, it dominated the morning sky until it was obliterated by the Sun. Shortly after its closer approach to the Earth, it began to decrease in apparent size and brightness, and at the end of June it appearance was ordinary.

On the 25th of the same month, he was seen faint and close to the horizon. From that night, attempts were unsuccessful until the search was canceled on 5 November. The observations consisted of determining the positions with a micrometer, photography, spectroscopy and photometry.

In the XVI century. astronomer Tycho Brahe followed him by many other researchers who found that comets are far beyond the earth's atmosphere and even much further than the Earth's satellite, the Moon; that they move in space at about the same long distance from the Earth, like the planets.

Later, at the end of the 17th century, the brilliant scientist Isaac Newton, assuming that comets, like planets and their satellites, obey the law gravity, for the first time determined the path around the Sun of one of the comets. It was the comet of 1680. It turned out that its path is an infinitely elongated curve - a parabola. After passing close to the Sun, this comet sped off into interstellar space and was never seen again.

In May, another observatory photographer, Robert Winter, joins this work. His wife's assistant, who was in charge of data recording, Dr. Perrin took numerous pictures with one, with the option of John Brashear and a mountain made by George Sagmuller purchased during Tom's administration. The purpose of this work was to study the structure of the tail. Plates were also made with this camera to measure the comet's brightness.

The difficulties encountered during these works were numerous, especially with the astrographic telescope, the director refers to all of them in the volume of 25 results. In addition, numerous renovations to the building violated this objective; unfavorable weather; failure of the exposure window and illness of the observer.

Newton's friend and student E. Halley determined the paths around the Sun of 24 comets. This hard work has led to interesting results; it turned out that three comets, observed at intervals of about 76 years, moved along almost identical paths.

Having carefully studied this question, Halley declared with full confidence that in reality not three different comets were observed, but one and the same. Halley calculated how long this comet would be visible again, and predicted its appearance in 1758. His prediction came true brilliantly. Thus it was proved that the movement of comets obeys the same laws as the movement of other comets. celestial bodies. The relatively short orbital period of Halley's comet (about 76 years) made it possible to observe it during successive appearances.

Discovery of Halley's Comet

But, without a doubt, the most unusual was the problem with a member of the observer's family, who almost died as a result of a row during a field day after a religious service. To close this long list of misfortunes, Perrin adds that during the best series of exhibitions, a light flare passed in front of the telescope lens when it was launched next to the commission!

Spectrometric studies were carried out using an objective prism. However, in March of the following year, the manufacturers stated that it was not possible for them to obtain a glass block in a short period of time. Given this circumstance, last minute efforts and thanks to the intervention of Prof. Emil Hermann Bose, Director of the Physics Laboratory of the University of La Plata, the 60° prisms were obtained on credit. The spectra were taken when the comet was brightest, in May and June. Two different lenses were used, the target of a small handheld telescope was 7.5 cm in diameter and 70 focal lengths, and one target was 5 cm in diameter and 18 focal lengths.

Sketches of this comet, made in ancient times, show that the comet even then looked exactly the same as in the era of Halley. What are the main structural features of a comet? The brightest part of it is the “head”. It looks like a condensed, misty cloud, the brightness of which increases towards the middle. Here you can sometimes see the "core" of the comet's head, similar to an asterisk. A "tail" emerges from the head of the comet in the form of a faint luminous band. Occasionally, comets were observed exceptionally bright: their brightness exceeded that of Venus or Jupiter. As long as the comet is away from the Sun, it does not have any tail. The tail appears and begins to grow as the comet approaches the Sun, and it is usually directed away from the Sun.

They were united in solidarity with the Great Equator Tube. Given that the spectrometric work was carried out using not very adequate instruments, and there was little of it, its results were mainly used to fill gaps in studies carried out at other observatories.

The most important study planned for Halley was to determine his brightness. To overcome the inconvenience of comparing a large image of a comet with punctual comparison stars, the method of out-of-focus photographs was used. In this case, photographs of the comet and its stellar environment are obtained by moving the plate from the focus position. In this way, the formed images turn out to be small circles, equal in size, thereby eliminating most of the difficulties.

Comet tails vary in length and shape. Some comets had tails stretching across the sky; in others they were barely noticeable. For example, the tail of the comet of 1744 was 20 million km long, while the tail of the comet of 1680 was 240 million km long. It can be calculated that if, with such dimensions, the substance of the comet's tail had a density of at least the same as water, then the force of attraction would force not only the planets, but also the Sun itself to revolve around this comet. Comets with such tails would be the most massive bodies solar system. In reality, the heads and especially the tails of comets are composed of extremely rarefied matter. The mass of comets is therefore negligible - billions of times less than the mass of the Earth, and the attraction exerted by a comet on the Sun and planets is so small that it cannot even be noticed.

Obtaining plates and their subsequent measurement proved to be a very difficult task. They had to solve numerous problems, which meant limiting measurements to the region near the comet's nucleus and at the time when it represented the highest brightness - from April 21 to June 12. A total of 40 plaques were achieved and measured 16 years later. It is not clear what are the reasons for such a large delay in the start of work. Perhaps this was due to the impossibility of solving the problems associated with the measurement, or the delay in the arrival of the photometer to perform them.

This, however, does not answer why the rest of the observations were not published. After evaluating several alternatives, it was decided to build a specific photometer for this purpose, using a photovoltaic tube purchased for automatic observation of transits with a meridian circle. The tool could be made thanks to the collaboration of electrical engineer J. Rodwell, an employee of the Central railway Cordova. The idea was to illuminate the plate and use a photoelectric tube to measure the light that passed through the images of the comet, as well as several nearby stars whose brightness was known.

In May 1910, the Earth passed through the tail of Halley's comet. At the same time, there were no changes in the motion of the Earth. Comet tails are so transparent that stars can be clearly seen through them. Thus, the tail of a comet can consist only of gas particles in a state of strong rarefaction, or of the smallest dust particles, or of a mixture of gas and dust.

The nucleus of a comet is solid and dense. It apparently consists of a mixture of frozen gases and dust particles and, apparently, stone blocks. The diameters of solid cometary nuclei range from a few meters to several kilometers. Therefore, the collision of the cometary nucleus with the Earth does not threaten the latter with any danger. When penetrating into the Earth's atmosphere, the frozen gases will quickly evaporate, and only debris will remain from the core, which cannot harm the Earth. So, the collision of the Earth with the nucleus of a comet is not terrible, and it can happen extremely rarely - once in tens or hundreds of thousands of years.

Comets are now discovered in the sky every year, sometimes even several comets a year. However, many of them can only be seen through a telescope, and then as hazy specks.