The Vega project (Venus - Halley's Comet) was one of the most complex in the history of space research. It consisted of three parts: the study of the atmosphere and surface of Venus with the help of landers, the study of the dynamics of the atmosphere of Venus with the help of balloon probes, the flight through the coma and the plasma shell of Halley's comet.

The automatic station "Vega-1" was launched from the Baikonur Cosmodrome on December 15, 1984, 6 days later it was followed by "Vega-2". In June 1985, they passed one after another near Venus, having successfully completed research related to this part of the project.

But the most interesting was the third part of the project - the study of Halley's comet. Spacecraft for the first time had to "see" the nucleus of a comet, elusive for ground-based telescopes. The meeting of Vega-1 with the comet took place on March 6, and Vega-2 on March 9, 1986. They passed at a distance of 8900 and 8000 kilometers from its core.

The most important task in the project was to study the physical characteristics of the comet's nucleus. For the first time, the core was considered as a spatially resolved object, its structure, dimensions, infrared temperature were determined, and estimates of its composition and characteristics of the surface layer were obtained.

At that time, it was not yet technically possible to land on the comet's nucleus, since the meeting speed was too high - in the case of Halley's comet, this is 78 km / s. It was dangerous even to fly too close, as cometary dust could destroy the spacecraft. The flyby distance was chosen taking into account the quantitative characteristics of the comet. Two approaches were used: remote measurements using optical instruments and direct measurements of matter (gas and dust) leaving the core and crossing the spacecraft's trajectory.

Optical instruments were placed on a special platform, developed and manufactured jointly with Czechoslovak specialists, which rotated during the flight and tracked the comet's trajectory. With its help, three scientific experiments were carried out: television filming of the nucleus, measurement of the infrared radiation flux from the nucleus (thus, the temperature of its surface was determined) and the infrared radiation spectrum of the internal "near-nuclear" parts of the coma at wavelengths from 2.5 to 12 micrometers in order to determine its composition. Investigations of IR radiation were carried out using an infrared spectrometer IKS.

The results of optical studies can be formulated as follows: the core is an elongated monolithic body of irregular shape, the dimensions of the major axis are 14 kilometers, and about 7 kilometers in diameter. Every day, several million tons of water vapor leave it. Calculations show that such evaporation can come from an icy body. But at the same time, the instruments found that the surface of the core is black (reflectivity less than 5%) and hot (about 100,000 degrees Celsius).

Measurements of the chemical composition of dust, gas and plasma along the flight path showed the presence of water vapor, atomic (hydrogen, oxygen, carbon) and molecular (carbon monoxide, carbon dioxide, hydroxyl, cyan, etc.) components, as well as metals with an admixture of silicates.

The project was implemented with broad international cooperation and with the participation of scientific organizations from many countries. As a result of the Vega expedition, scientists first saw the cometary nucleus, received a large amount of data on its composition and physical characteristics. The rough diagram was replaced by a picture of a real natural object that had never been observed before.

NASA was preparing three large expeditions. The first of these is called "Stardust" ("Stardust"). It assumed the launch in 1999 of a spacecraft that passed 150 kilometers from the nucleus of comet Wild 2 in January 2004. Its main task was to collect comet dust for further research using a unique substance called "aerogel".

The second project is called "Contour" ("COmet Nucleus TOUR"). The device was launched in July 2002. In November 2003, he met with the comet Encke, in January 2006 - with the comet Schwassmann-Wachmann-3, and, finally, in August 2008 - with the comet d "Arrest. He was equipped with advanced technical equipment, which made it possible to obtain high-quality photographs nuclei in different spectra, as well as to collect cometary gas and dust.The project is also interesting because the spacecraft with the help of the Earth's gravitational field was reoriented in 2004-2008 to a new comet.

The third project is the most interesting and difficult. It is called "Deep Space 4" and is part of a research program called the "NASA New Millennium Program". It was supposed to land on the nucleus of comet Tempel 1 in December 2005 and return to Earth in 2010. The spacecraft explored the comet's nucleus, collected and delivered soil samples to Earth.

The most interesting events over the past few years have been: the appearance of the Hale-Bopp comet and the fall of the comet Schumacher-Levy 9 to Jupiter. Comet Hale-Bopp appeared in the sky in the spring of 1997. Its period is 5900 years. There are some interesting facts connected with this comet. In the fall of 1996, American amateur astronomer Chuck Shramek transmitted to the Internet a photograph of a comet, which clearly showed a bright white object of unknown origin, slightly flattened horizontally. Shramek called it "Saturn-like object" (Saturn-like object, abbreviated as "SLO"). The size of the object was several times larger than the size of the Earth. The reaction of official scientific representatives was strange. The picture of Shramek was declared a fake, and the astronomer himself was a hoaxer, but no intelligible explanation for the nature of SLO was offered. The picture posted on the Internet caused an explosion of occultism, with a huge number of stories about the coming end of the world, the "dead planet of an ancient civilization", evil aliens preparing to take over the Earth with a comet, even the expression: "What the hell is going on?" (“What the hell is going on?”) was paraphrased into “What the Hale is going on?”… It is still not clear what kind of object it was, what its nature is.

Preliminary analysis showed that the second "core" is a star in the background, but subsequent images disproved this assumption. Over time, the "eyes" connected again, and the comet took on its original form. This phenomenon has also not been explained by any scientist.

Thus, the Hale-Bopp comet was not a standard phenomenon, it gave scientists a new reason to think.

Another sensational event was the fall in July 1994 of the short-period comet Schumacher-Levy 9 on Jupiter. The nucleus of the comet in July 1992, as a result of its approach to Jupiter, was divided into fragments, which subsequently collided with the giant planet. Due to the fact that the collisions took place on the night side of Jupiter, earthly researchers could only observe flashes reflected by the planet's satellites. The analysis showed that the diameter of the fragments is from one to several kilometers. 20 comet fragments fell on Jupiter.

Scientists say that the breakup of a comet into pieces is a rare event, the capture of a comet by Jupiter is an even rarer event, and the collision of a large comet with a planet is an extraordinary cosmic event.

Recently, in an American laboratory, on one of the most powerful computers Intel Teraflop with a capacity of 1 trillion operations per second, a model of a comet falling with a radius of 1 kilometer to Earth was calculated. The calculations took 48 hours. They showed that such a cataclysm would be fatal for mankind: hundreds of tons of dust would rise into the air, blocking access to sunlight and heat, a giant tsunami would form when it fell into the ocean, and destructive earthquakes would occur. According to one hypothesis, dinosaurs became extinct as a result of the fall of a large comet or asteroid. In the state of Arizona, there is a crater with a diameter of 1219 meters, formed after the fall of a meteorite 60 meters in diameter. The explosion was equivalent to the explosion of 15 million tons of TNT. It is assumed that the famous Tunguska meteorite of 1908 had a diameter of about 100 meters. Therefore, scientists are now working on the creation of a system for the early detection, destruction or deflection of large space bodies flying near our planet.

The most interesting research promises to be the mission of the European Space Agency to the comet Churyumov-Gerasimenko, discovered in 1969 by Klim Churyumov and Svetlana Gerasimenko. The automatic station "Rosetta" was launched in 2004 and it is expected that the device will approach the comet in November 2014, during the period when it will still be far from the Sun and, accordingly, will not be active yet, in order to follow the development of cometary activity. . The station will orbit the comet for 2 years. For the first time in the history of comet research, it is planned to lower a landing module to the nucleus, which will take soil samples and explore directly on board, and will also transmit to Earth numerous photographs of gas jets escaping from the comet's nucleus.

Everything that happens in heaven has long interested man. Comets flying across the sky usually inspired fear and awe. Let's get acquainted with interesting facts about comets.

Under the influence of gravity, most comets leave the solar system for millions of years. Losing their ice, they fall apart as they move.

The Chinese were the first to document the appearance of Halley's Comet. It began in 240 BC.

Telling interesting facts about comets, it is necessary to explain the word comet itself. To the ancient Greeks, comets resembled stars with flowing hair flying across the sky. The word "comet" comes from the Greek word for "long-haired".

A change in the direction of a comet's flight can occur for several reasons. When they pass close enough to the planet, the path of movement may change slightly under its influence. The planet most suitable for changing the path of a comet is Jupiter. This is the largest planet. Spacecraft and telescopes were able to capture the image of a comet that crashed in a collision with the atmosphere of Jupiter. Her name is Shoemaker-Levy 9. Sometimes comets moving towards the Sun hit it exactly.

Comets, which have been traveling for over 4.5 billion years, are made up of dust, ice, rocky material and gases brought from the far reaches of the solar system.

Comets, like the planets of the solar system, rotate around the Sun.

Comets far from the Sun do not have a tail. As they approach the Sun, under the ever-increasing influence of its heat, the melting of the comet's nucleus begins. The solar wind from the molten core blows the comet's tail.

Comets that are far from the sun are cold and completely dark objects. The nucleus contains 90% of the comet's mass. In its center is a small stone core. The remaining components are ice, dirt and dust. Ice is a mixture of frozen water mixed with ammonia, methane and carbon.

Relative to the Universe, comets are so small that scientists have not yet had a chance to observe them outside our solar system.

Astronomers have found that there are about two million comets in the solar system. An average of five new comets are discovered each year. The total number of registered comets exceeds three thousand.

We invite you to watch an interesting video where you can see how a huge comet rammed the sun:

> Research

Learn History comet research: missions, spacecraft launches, photos of Hubble comets, significant dates, study of Halley's comet, flight and descent of Rosetta.

The researchers dreamed of studying these objects, so they examined in detail the images of Halley's comet, obtained in 1986. In 2001, Deep Space 1 flew past the Borelli object and captured its 8 km long core.

In 2004, the Stardust mission successfully flew 236 km past Comet Wild 2, mining particles and interstellar dust. Photos show dust jets and a durable textured surface. Sample analysis shows that comets can be much more complex than previously thought. Minerals involved in the formation near the Sun and others have been found.

The Deep Impact project consisted of several spacecraft and a striker. In 2005, he was sent to the nucleus of comet Tempel-1. This led to the ejection of small fragments and helped to calculate the composition and flight path.

The EPOXI mission consisted of two projects: the study of the Hartley 2 comets in 2010 and the search for terrestrial planets around others.

November 12, 2014 marked another remarkable mission in the history of space exploration. After 10 years of flight, the ESA Rosetta apparatus reached the comet 67P / Churyumov-Gerasimenko and brought Fila to the surface. This is the most grandiose event in the study of comets.

In the same year, the Hubble telescope managed to capture comet C / 2013 A1 in a photo when it approached the Red Planet as close as possible.

Small bodies like asteroids or comets act as "time capsules" containing information about the history of our system. Missions like Rosetta help to advance the study of this issue, as they offer to examine the extracted samples. NASA expects to create more robotic projects to explore such objects at close range.

Comets and asteroids are fragments left after the formation of planets and satellites in the solar system. These tiny celestial bodies orbit the Sun and are found in the Kuiper Belt and the Oort Cloud. Most of the asteroids are located between Mars and Jupiter. Sometimes gravitational fluctuations cause them to be pushed out of their usual place and closer to us. Near-Earth object (NEO) refers to all the rocks located within 50 million km from us.

The presence of crater scars on planets and moons suggests that ancient objects often succumbed to attacks. In the first billion years of existence, the collision heated the earth's surface, which set the stage for the appearance of a sufficient amount of water and carbon-based molecules. Life appeared about 3.8 billion years ago.

Watching the OZO, you can find out the details of the composition. Further reviews will allow you to understand the exact components of the building blocks of life. Objects close to our planet are especially interesting, as they allow us to understand the origins of life on our planet.

Already, they are preparing new missions to explore the planets. In 2018, they plan to send the Japanese Hayabusa-2 probe to the asteroid 1999JU3 for samples that can deliver them in 2020. Ben and 1999 RQ36 were sent OSIRIS-Rex in 2016. In 2019, he should take samples and arrive with them in 2023. The main goal of the missions is to find a source of organic materials and water.

Hayabusa-2 and OSIRIS-Rex will help NASA select a target for the first mission to capture and transport an asteroid. The task is being prepared for the 2020s. and are developing technologies to get people to Mars. To do this, they are going to launch a robotic ship for docking with OZO. Now the agency thinks that it is possible to influence a fragment with a diameter of 5-10 m with an inflatable mechanism (2-5 m) using a robotic arm. The machine then uses its power to change the object's trajectory.

You can also drag the asteroid to the moon base and study it further in the laboratory. In the samples, there is a chance to find interstellar particles. It remains only to wait. Below are the spacecraft used to study comets and significant dates.

Significant dates:

• 1070-1080 g. - Halley's comet is displayed in the Bayeux Tapestry (battle of Hastings in 1066);
• 1449-1450- scientists undertake one of the first attempts to fix the trajectory of comets across the sky;
• 1705- Edmund Halley found out that the objects of 1531, 1607 and 1682 represent a single comet, which should return in 1758. His prediction came true and the body was named after him;
• 1986- an international fleet of 5 spacecraft monitors Halley's Comet (arrives every 76 years) passing into the inner system;
• 1994– researchers see fragments of comet Shoemaker-Levy 9 crash into Jupiter's atmosphere;
• 2001– Deep Space 1 rushes past Comet Borelli and produces images up close;
• 2004- NASA's Stardust spacecraft collects dust samples from comet Wild 2 and photographs the nucleus;
• 2005- Deep Impact impactor collides with Tempel-1 to study the internal composition of the core;
• 2009– researchers report that the building block of life glycine was obtained on the comet Wild-2;
• 2010– the Deep Impact apparatus examines Hartley-2;
• 2011– the Stardust apparatus approaches Tempel-1, photographs the opposite side of the core and notes the evolution of the surface layer;

Comets are of interest to many people. These celestial bodies capture young and old people, women and men, professional astronomers and just amateur astronomers. And our portal site offers the most up-to-date news about the latest discoveries, photos and videos of comets, as well as a lot of other useful information that you can find in this section.

Comets are small celestial bodies revolving around the Sun in a conic section with a rather stretched orbit, having a foggy appearance. When a comet approaches the Sun, it forms a coma and sometimes a tail of dust and gas.

Scientists suggest that periodically comets arrive in the solar system from the Oort cloud, as it contains many cometary nuclei. As a rule, bodies located on the outskirts of the solar system consist of volatile substances (methane, water and other gases), which evaporate during the approach to the Sun.

To date, more than four hundred short-period comets have been identified. Moreover, half of them were in more than one passage of perihelion. Most of them belong to families. For example, many short-period comets (revolve around the Sun in 3-10 years) form the Jupiter family. Few are the families of Uranus, Saturn and Neptune (the famous comet Halley belongs to the latter).

Comets that come from the depths of space are nebulous objects with a trailing tail. It often reaches several million kilometers in length. As for the nucleus of a comet, it is a body of solid particles, shrouded in a coma (foggy shell). A core 2 km in diameter could have a coma 80,000 km across. The sun's rays knock gas particles out of the coma and throw them back, pulling them into a smoky tail moving behind it in outer space.

The brightness of comets largely depends on how far they are from the Sun. Of all the comets, only an insignificant part approaches the Earth and the Sun so much that they can be seen with the naked eye. Moreover, the most noticeable of them are usually called "great (large) comets."

Most of the “shooting stars” (meteorites) we observe are of cometary origin. These are the particles lost by the comet, which burn up when they enter the atmosphere of the planets.

Comet nomenclature

For all the years of studying comets, the rules for naming them have been clarified and changed many times. Until the beginning of the 20th century, many comets were simply named by the year they were discovered, often with additional clarifications regarding the season of the year or brightness if there were several comets that year. For example, "The Great September Comet of 1882", "The Great January Comet of 1910", "The Daytime Comet of 1910".

After Halley was able to prove that the comets of 1531, 1607 and 1682 represent the same comet, it was called Halley's comet. He also predicted that in 1759 she would return. The second and third comets were named by Bela and Encke in honor of the scientists who calculated the orbit of the comets, despite the fact that the first comet was observed by Messier, and the second by Méchain. A little later, periodic comets were named after their discoverers. Well, those comets that were observed in only one passage of perihelion were called, as before, according to the year of appearance.

At the beginning of the 20th century, when comets began to be discovered more often, a decision was made on the final naming of comets, which has been preserved to this day. Only when three independent observers identified the comet did it get a name. A lot of comets have been discovered in recent years through instruments that have been detected by entire teams of scientists. Comets in such cases are named after instruments. For example, comet C/1983 H1 (IRAS - Araki - Alcock) was discovered by the IRAS satellite, George Alcock and Genichi Araki. In the past, another team of astronomers discovered periodic comets, to which they added a number, for example, comets Shoemaker-Levy 1-9. Today, a huge number of planets are discovered with a variety of instruments, which made this system impractical. Therefore, it was decided to resort to a special system for designating comets.

Until early 1994, comets were given temporary designations that consisted of the year of discovery plus a lowercase Latin letter indicating the order in which they were discovered that year (for example, comet 1969i was the 9th comet that was discovered in 1969). Once a comet had passed perihelion, its orbit was established and it was given a permanent designation, namely the year of the perihelion passage plus a Roman number which indicates the order of perihelion passage for that year. For example, comet 1969i was given the permanent designation 1970 II (meaning it was the second comet to pass perihelion in 1970).

As the number of discovered comets increased, this procedure became very inconvenient. Therefore, the International Astronomical Union in 1994 adopted a new system for designating comets. Today, the name of comets includes the year of discovery, the letter representing the half of the month in which the discovery took place, and the number of the discovery itself in that half of the month. This system resembles the one used for naming asteroids. Thus, the fourth comet, which was discovered in 2006, has the designation 2006 D4 in the second half of February. A prefix is ​​also placed before the designation. He explains the nature of the comet. It is customary to use the following prefixes:

· C/ - long-period comet.

· P/ - short-period comet (one that was observed in two or more passages of perihelion, or a comet whose period is less than two hundred years).

· X/ - a comet for which it was not possible to calculate a reliable orbit (most often for historical comets).

· A/ - objects mistaken for comets, but turned out to be asteroids.

· D/ - comets were lost or destroyed.

The structure of comets

Gas components of comets

Core

The nucleus is the solid part of the comet, where almost all of its mass is concentrated. At the moment, the nuclei of comets are not available for study, as they are hidden by constantly formed luminous matter.

The core, according to the most common Whipple model, is a mixture of ice with the inclusion of particles of meteoric matter. The layer of frozen gases, according to this theory, alternates with dust layers. Gases evaporate as they heat up, carrying clouds of dust with them. Thus, the formation of dust and gas tails in comets can be explained.

But according to the results of studies that were carried out with the help of an American automatic station in 2015, the core is made up of loose material. This is a lump of dust with pores that occupy up to 80 percent of its volume.

Coma

Coma is a light cloudy shell that surrounds the core, consisting of dust and gases. Most often, it stretches from 100 thousand to 1.4 million km from the core. Under high pressure light is deformed. As a result, it is stretched in the antisolar direction. Together with the coma nucleus, it forms the comet's head. Usually a coma consists of 4 main parts:

• internal (chemical, molecular and photochemical) coma;
• visible coma (or it is also called a coma of radicals);
• atomic (ultraviolet) coma.

Tail

As bright comets approach the Sun, a tail is formed - a faint luminous band, which most often, as a result of the action of sunlight, is directed away from the Sun in the opposite direction. Despite the fact that the coma and tail contain less than one millionth of the comet's mass, almost 99.9% of the glow that we see during the comet's passage through the sky consists of gas formations. This is because the core has a low albedo and is itself very compact.

Comet tails can vary in both shape and length. For some, they stretch across the sky. For example, the tail of a comet seen in 1944 was 20 million km long. Even more impressive is the length of the tail of the Great Comet of 1680, which was 240 million km. There have also been cases when the tail separates from the comet.

The tails of comets are practically transparent and do not have sharp outlines - stars are clearly visible through them, since they are formed from super rarefied matter (its density is much less than the density of gas from a lighter). As for the composition, it is diverse: the smallest dust particles or gas, or a mixture of both. The composition of most of the dust particles resembles asteroid materials, which was revealed as a result of the study by the Stardust spacecraft of the comet 81P / Wild. We can say that this is "visible nothingness": we can see the tails of comets only for the reason that the dust and gas glow. Moreover, the combination of gas is directly related to its ionization by UV rays and particle flows that are ejected from the solar surface, and dust scatters sunlight.

At the end of the 19th century, astronomer Fyodor Bredikhin developed the theory of shapes and tails. He also created a classification of comet tails, which is still used in astronomy to this day. He proposed that the tails of comets be classified into three main types: narrow and straight, directed away from the Sun; curved and wide, deviating from the central luminary; short, strongly deviated from the Sun.

Astronomers explain such different shapes of comet tails as follows. The constituent particles of comets have different properties and composition and react differently to solar radiation. Therefore, the paths of these particles in space "diverge", as a result of which the tails of space travelers get different shapes.

Study of comets

Mankind has been interested in comets since ancient times. Their unexpected appearance and unusual appearance served for many centuries as a source of various superstitions. The ancients associated the appearance in the sky of these cosmic bodies with a brightly luminous tail with the onset of difficult times and impending troubles.

Thanks to Tycho Brahe in the Renaissance, comets began to refer to celestial bodies.

People gained a more detailed understanding of comets thanks to a trip in 1986 to Halley's comet on spacecraft such as Giotto, as well as Vega-1 and Vega-2. The devices installed on these devices transmitted images of the comet's nucleus and various information about its shell to Earth. It turned out that the nucleus of a comet is composed mainly of simple ice (with minor inclusions of methane and carbon dioxide ices) and field particles. Actually, they form the shell of the comet, and as it approaches the Sun, some of them, under the influence of the pressure of the solar wind and sunlight, pass into the tail.

According to scientists, the dimensions of the nucleus of Halley's comet are several kilometers: 7.5 km in the transverse direction, 14 km in length.

The nucleus of Halley's comet has an irregular shape and constantly rotates around an axis, which, according to the assumptions of Friedrich Bessel, is almost perpendicular to the plane of the comet's orbit. As for the rotation period, it was 53 hours, which was in good agreement with the calculations.

NASA's Deep Impact spacecraft dropped a probe on comet Tempel 1 in 2005, which made it possible to transmit an image of its surface.

Study of comets in Russia

The first information about comets appeared in The Tale of Bygone Years. It was clear that the chroniclers paid special attention to the appearance of comets, since they were considered harbingers of various misfortunes - pestilence, wars, etc. But in the language of Ancient Russia, they were not given any separate name, since they were considered tailed stars moving across the sky. When the description of the comet appeared on the pages of chronicles (1066), the astronomical object was called “the star is great; star image of a copy; a star ... emitting a ray, by which I call a sparkler.

The concept of "comet" appeared in Russian after the translation of European writings, which dealt with comets. The earliest mention was seen in the collection "Golden Beads", which is something like a whole encyclopedia about the world order. At the beginning of the 16th century, Lucidarius was translated from German. Since the word was new for Russian readers, the translator explained it with the familiar name “star”, namely “the star of the comita gives a glint from itself like a ray”. But the concept of "comet" firmly entered the Russian language only in the middle of the 1660s, when comets actually appeared in the European sky. This event aroused particular interest. Russians learned from translated works that comets bear little resemblance to stars. Until the beginning of the 18th century, the attitude to the appearance of comets as signs was preserved both in Europe and in Russia. But then the first writings appeared that denied the mysterious nature of comets.

Russian scientists mastered European scientific knowledge about comets, which allowed them to make a significant contribution to their study. Astronomer Fyodor Bredinikh in the second half of the 19th century built a theory of the nature of comets, explaining the origin of tails and their bizarre variety of shapes.

For all those who want to learn more about comets, learn about current news, our portal site offers to follow the materials in this section.

Theories on the origin of comets

To date, there is no single theory of the origin of comets accepted by all specialists. Actually, this is the first mystery of these celestial bodies - how, where and under the influence of what factors do they appear? According to one of the hypotheses, quite ancient, but still having its supporters, comets are formed from materials that are ejected as a result of volcanic activity from the bowels of the giant planets of the solar system, Jupiter and Saturn. A more modern hypothesis puts forward as the birthplace of comets a distant part of the solar system, the so-called Oort cloud, in which, according to assumptions, comets formed simultaneously with the planets. They allegedly stay there until the attraction of the sun and planets gradually pulls out one comet, which begin their space journey. . There is also an opinion that comets generally come from outside the solar system, so it is still difficult to establish the mechanism of their formation in the conditions of the modern development of space exploration.

Visibility and invisibility of comets

The philistine consciousness firmly compares comets with a celestial body that has a long and extensive plume or tail. Comets are indeed often characterized by the presence of such tails. But it turns out that if a comet has no visible plume, this does not mean that it does not exist. Whether the tail of a comet is visible or not, and how bright and extensive it is, depends primarily on the proximity of a particular comet to the Sun. The mechanism of the impact of the solar wind on the particles that make up the so-called cloudy body of a comet, which moves along with the nucleus, is not yet clear to scientists. However, the fact remains that as they approach the Sun, the visibility of comets and the brightness of their plumes increase significantly. Versions are put forward that this mechanism is akin to the mechanism of resonant fluorescence or the aurora, but so far these are only hypotheses.

Dust in the eyes of scientists

The cloud body of comets consists, among other things, of cosmic dust - this is an obvious given for all space explorers. However, not so long ago it was discovered that some of the cosmic dust that makes up the comet was formed under the influence of high temperatures. And this is something that is a mystery to scientists, because the main part of comets is most often ice, both as the nucleus of a comet, and ice dust in the tail of a celestial body. The question naturally arises - how can even the icy core of a comet contain cosmic dust formed at high temperatures? It has already been suggested that comets are formed in different parts of the solar system from materials that have different physical properties, including absorbing thermal energy with different intensity during their movement through outer space.

Space "weather forecast": no guarantees either...

For teachers of the Earth, comets are divided, first of all, according to the frequency of circulation in their orbits, into which they fall at a certain moment and begin their movement relative to the Sun. This division makes it possible to distinguish between short-period (orbital duration less than 150 years), medium-period (rotation duration from 150 to 200 years) and long-period (orbital duration over 200 years) comets. The problem is that any comet, and literally at any moment, can significantly change the trajectory of its movement and, consequently, the direction and duration of its orbit. Because comets are very susceptible to the gravitational influence of the planets they pass near, and it is impossible to predict changes in the trajectory of their movement under these influences. A certain correction to the orbits of closely passing comets is reported by such a small planet as the Earth, then what can we say about a giant, for example, Jupiter. Therefore, scientists, of course, make up the trajectories of comets, and at the same time forecasts for them, but these calculations always have a considerable share of relativity.

Comets with unusual behavior

One of the most extravagant assumptions about some of the comets is the hypothesis that some celestial objects that astronomers have identified as comets are actually alien spaceships. . Most often, the “suspects” are the comet Denning, which, allegedly suspicious for a comet, alternately described circles around Jupiter, Venus, Mars and the earth (as if these were familiarization flights). Also, the Arena-Roland comet is often mentioned, which supposedly had two tails, moreover, differently directed - this dismisses the traditional cause of comet tails in the form of the solar wind and suggests the presence of multidirectional rocket engines on the spacecraft. In response, representatives of official scientific departments cite data that long-term observation of these comets did not reveal any "special" signs.