Since ancient times, people have sought to reveal the secrets that the sky is fraught with. Since the creation of the first telescope, scientists have begun to collect, step by step, the grains of knowledge that are hidden in the boundless expanses of space. It's time to find out where the messengers from space came from - comets and meteorites.
What is a comet?
If we investigate the meaning of the word "comet", then we come to its ancient Greek equivalent. It literally means "with long hair." Thus, the name was given due to the structure of this. The comet has a "head" and a long "tail" - a kind of "hair". The comet's head consists of a nucleus and perinuclear substances. The loose core can contain water as well as gases such as methane, ammonia and carbon dioxide. Comet Churyumov - Gerasimenko, discovered on October 23, 1969, has the same structure.
How the comet was imagined before
In ancient times, our ancestors were in awe of her and invented various superstitions. Even now, there are those who associate the appearance of comets with something ghostly and mysterious. Such people may think that they are wanderers from another world of souls. Where did this come from? Perhaps the whole point is that the appearance of these heavenly creatures has ever coincided with some bad incident.
However, time passed, and the idea of what small and large comets were, changed. For example, a scientist like Aristotle, studying their nature, decided that it is a luminous gas. Over time, another philosopher named Seneca, who lived in Rome, put forward the assumption that comets are bodies in the sky moving in their orbits. However, it was only after the creation of the telescope that it was possible to make real progress in their study. When Newton discovered the law of gravitation, things went up.
Current concepts of comets
Scientists have now established that comets are composed of a solid core (1 to 20 km thick). What is a comet nucleus made of? From a mixture of frozen water and cosmic dust. In 1986, pictures of one of the comets were taken. It became clear that its fiery tail is the release of a stream of gas and dust, which we can observe from the earth's surface. What is the reason for this "fiery" ejection? If an asteroid flies very close to the Sun, then its surface is heated, which leads to the release of dust and gas. Solar energy puts pressure on the solid material that makes up a comet. As a result, a fiery tail of dust is formed. These debris and dust are part of the trail that we see in the sky when we observe the movement of comets.
What determines the shape of the comet's tail
The report on comets below will help you better understand what comets are and how they work. They are different - with tails of all kinds. It's all about the natural composition of the particles that make up this or that tail. Very small particles quickly fly away from the Sun, while those that are larger, on the contrary, tend to the star. What is the reason? It turns out that the former move away, pushed by solar energy, and the latter are affected by the gravitational force of the Sun. As a result of the operation of these physical laws, we get comets, the tails of which are bent in different ways. Those tails, which are mostly composed of gases, will be directed from the star, and corpuscular (consisting mainly of dust), on the contrary, tend to the Sun. What about the density of the comet's tail? Usually cloud tails can measure in millions of kilometers, in some cases hundreds of millions. This means that, unlike the body of a comet, its tail consists mostly of discharged particles without practically any density. When an asteroid approaches the Sun, the comet's tail can split in two and acquire a complex structure.
The speed of movement of particles in a cometary tail
Measuring the speed of a comet's tail is not easy because we cannot see individual particles. However, there are times when the speed of movement of matter in the tail can be determined. Gas clouds can sometimes condense there. From their movement, you can calculate the approximate speed. So, the forces moving the comet are so great that the speed can be 100 times higher than the attraction of the Sun.
How much does a comet weigh
The entire mass of comets depends to a large extent on the weight of the comet's head, or rather, its nucleus. Presumably, a small comet can weigh only a few tons. Whereas, according to forecasts, large asteroids can reach a weight of 1,000,000,000,000 tons.
What are meteors
Sometimes a comet passes through the Earth's orbit, leaving a trail of debris in its wake. When our planet passes in the place where the comet was, these debris and the cosmic dust left from it enter the atmosphere at a tremendous speed. This speed reaches more than 70 kilometers per second. When fragments of a comet burn up in the atmosphere, we see a beautiful trail. This phenomenon is called meteors (or meteorites).
Comet age
Fresh asteroids of enormous size can live for trillions of years in space. However, comets, like any comets, cannot exist forever. The more often they approach the Sun, the more they lose solid and gaseous substances that make up their composition. "Young" comets can lose weight very strongly until a kind of protective crust forms on their surface, which prevents further evaporation and burnout. Nevertheless, the "young" comet is aging, and the nucleus is decrepit and loses its weight and size. Thus, the superficial crust acquires many wrinkles, cracks and fractures. Gas streams, burning, push the body of the comet forward and forward, imparting speed to this traveler.
Halley's comet
Another comet, the structure of the same as the comet Churyumov - Gerasimenko, is an asteroid discovered. He realized that comets have long elliptical orbits along which they move with a large interval of time. He compared the comets that were observed from the earth in 1531, 1607 and 1682. It turned out that it was the same comet, which moved along its trajectory after a time interval equal to approximately 75 years. In the end, she was named after the scientist himself.
Comets in the solar system
We are in the solar system. Not less than 1000 comets were found not far from us. They are divided into two families, and they, in turn, are divided into classes. To classify comets, scientists take into account their characteristics: the time it takes for them to travel all the way through their orbit, as well as the period from circulation. If we take Halley's comet, mentioned earlier, as an example, it takes less than 200 years to complete a revolution around the sun. It belongs to periodic comets. However, there are those that travel all the way in much shorter periods of time - the so-called short-period comets. We can be sure that there are a huge number of periodic comets in our solar system, the orbits of which pass around our star. Such celestial bodies can move away from the center of our system so far that they leave behind Uranus, Neptune and Pluto. Sometimes they can get very close to planets, which is why their orbits change. An example is
Information about comets: long-period
The trajectory of motion of long-period comets is very different from short-period comets. They go around the Sun from all sides. For example, Heyakutake and Hale-Boppa. The latter looked very spectacular when they last approached our planet. Scientists have calculated that the next time they can be seen from Earth will only be thousands of years later. A lot of comets with a long period of motion can be found at the edge of our solar system. Back in the middle of the 20th century, a Dutch astronomer suggested the existence of a cluster of comets. After a while, the existence of a comet cloud was proved, which is known today as the "Oort Cloud" and was named after the scientist who discovered it. How many comets are there in the Oort Cloud? According to some assumptions, no less than a trillion. The period of motion of some of these comets can be equal to several light years. In this case, the comet will cover its entire path in 10,000,000 years!
Fragments of Comet Shoemaker - Levy 9
Reports of comets from around the world help in their exploration. Astronomers could observe a very interesting and impressive vision in 1994. More than 20 debris left over from Comet Shoemaker - Levy 9 collided with Jupiter at an insane speed (approximately 200,000 kilometers per hour). Asteroids flew into the planet's atmosphere with flares and huge explosions. The hot gas influenced the formation of very large fiery spheres. The temperature to which the chemical elements have warmed up is several times higher than the temperature that is recorded on the surface of the Sun. Then a very high column of gas could be seen through telescopes. Its height has reached enormous dimensions - 3200 kilometers.
Biela's comet is a double comet
As we have already learned, there is ample evidence that comets disintegrate over time. Because of this, they lose their brightness and beauty. Only one example of such a case can be considered - the comet Biela. It was first discovered in 1772. However, later it was noticed more than once again in 1815, after - in 1826 and in 1832. When it was observed in 1845, it turned out that the comet looks much larger than before. Six months later, it turned out that it was not one, but two comets that were walking next to each other. What happened? Astronomers have established that Biela's asteroid split in two a year ago. For the last time, scientists have registered the appearance of this miracle comet. One part of her was much brighter than the other. She was never seen again. However, after a while, a meteorite stream was more than once striking, the orbit of which exactly coincided with the orbit of comet Biela. This case proved that comets are capable of disintegrating over time.
What happens in a collision
For our planet, a meeting with these heavenly bodies does not bode well. A large comet or meteorite about 100 meters in size exploded high in the atmosphere in June 1908. As a result of this disaster, many reindeer died and two thousand kilometers of taiga were tumbled down. What would happen if such a block burst over a large city such as New York or Moscow? It would cost millions of lives. What would happen if a comet with a diameter of several kilometers hit the Earth? As mentioned above, in mid-July 1994 was "fired" by the debris of the comet Shoemaker - Levy 9. Millions of scientists watched what was happening. How would such a collision end for our planet?
Comets and the Earth - the views of scientists
The information scientists know about comets instills fear in their hearts. Astronomers and analysts with horror paint in their minds terrible pictures - a collision with a comet. When an asteroid hits the atmosphere, it will cause destruction inside the space body. It will explode with a deafening sound, and on Earth it will be possible to observe a column of meteorite debris - dust and stones. The sky will be engulfed in a fiery red glow. There will be no vegetation left on Earth, since all forests, fields and meadows will be destroyed due to the explosion and debris. Due to the fact that the atmosphere will become impenetrable to sunlight, it will suddenly become cold, and plants will not be able to perform the role of photosynthesis. This will disrupt the feeding cycles of marine life. Without food for a long time, many of them will die. All of the above events will affect natural cycles. Widespread acid rain will adversely affect the ozone layer, making it impossible to breathe on our planet. What happens if a comet falls into one of the oceans? Then it can lead to devastating environmental disasters: the formation of tornadoes and tsunamis. The only difference is that these cataclysms will be on a much larger scale than those that we could experience on ourselves for several thousand years of human history. Huge waves of hundreds or thousands of meters will sweep away everything in their path. Nothing will be left of settlements and cities.
"Don't worry"
Other scientists, on the contrary, say that there is no need to worry about such cataclysms. According to them, if the Earth comes close to a celestial asteroid, it will only lead to the illumination of the sky and a meteor shower. Is it worth worrying about the future of our planet? Is there a chance that we will ever be met by a flying comet?
Falling comet. Should you be afraid
Can you trust everything that scientists represent? Do not forget that all the information about comets written above are just theoretical assumptions that cannot be verified. Of course, such fantasies can sow panic in the hearts of people, but the likelihood that something like this will ever happen on Earth is negligible. Scientists who study our solar system marvel at how thoughtful everything is in its design. It is difficult for meteorites and comets to reach our planet as it is protected by a giant shield. The planet Jupiter, due to its size, has tremendous gravity. Therefore, it often protects our Earth from flying past asteroids and comet remnants. The place in which our planet is located leads many to the idea that the entire device was thought out and designed in advance. And if this is so, and you are not a zealous atheist, then you can sleep peacefully, because the Creator will undoubtedly save the Earth for the purpose for which he created it.
The names of the most famous
Reports of comets from various scientists around the world constitute a huge database of information about cosmic bodies. Among the most famous are several. For example, comet Churyumov - Gerasimenko. In addition, in this article we could get acquainted with the comet Fumaker - Levy 9 and comets Encke and Halley. In addition to them, Sadulayev's comet is known not only to sky researchers, but also to amateurs. In this article, we have tried to provide the most complete and verified information about comets, their structure and contact with other celestial bodies. However, as it is impossible to embrace all the expanses of space, it will not be possible to describe or enumerate all the comets known at the moment. Brief information about the comets of the solar system is presented in the illustration below.
Sky exploration
The knowledge of scientists, of course, does not stand still. What we know now was not known to us some 100 or even 10 years ago. We can be sure that man's tireless desire to explore the vastness of space will continue to push him to attempts to understand the structure of celestial bodies: meteorites, comets, asteroids, planets, stars and other more powerful objects. Now we have penetrated into such vast spaces of space that thinking about its immensity and inconceivability plunges into awe. Many agree that all this could not have appeared on its own and without a purpose. Such a complex structure must have an intention. However, many questions related to the structure of space remain unanswered. It seems that the more we learn, the more reasons we have to explore further. In fact, the more information we acquire, the more we understand that we do not know our solar system, our Galaxy, and even more so the Universe. However, all this does not stop astronomers, and they continue to struggle further on the mysteries of life. Each comet flying nearby is of particular interest to them.
Computer program "Space Engine"
Fortunately, today not only astronomers can explore the Universe, but also ordinary people, whose curiosity prompts them to do this. Not so long ago, a program for computers “Space Engine” was released. It is supported by most modern mid-range computers. It can be downloaded and installed completely free of charge using an Internet search. Thanks to this program, information about comets for children will also be very interesting. It presents a model of the entire Universe, including all comets and celestial bodies that are known to modern scientists today. To find a space object of interest to us, for example, a comet, you can use the oriented search built into the system. For example, you need comet Churyumov - Gerasimenko. In order to find it, you must enter its serial number 67 R. If you are interested in another object, for example, Sadulayev's comet. Then you can try to enter its name in Latin or enter its special number. Thanks to this program, you can learn more about cosmic comets.
76 years after its appearance in 1910, Halley's comet reappeared in the vicinity of the Sun and Earth. For this appearance, a thorough preparation of all observational facilities of the end of the 20th century was made; it was envisaged to send spacecraft for direct contact of research instruments with comet matter.
Five vehicles were launched: Vega-1 and Vega-2 (USSR), Giotto (European countries) and Suisen and Sakigake (Japan). All of them successfully coped with their tasks. The meetings took place when the comet, after passing through the perihelion on February 9, crossed the plane of the earth's orbit on March 6-9-11-14 at oncoming speeds of about 70 km / s for "Giotto" and almost 80 km / s for "Vega-1".
rice. 237. Images of the nucleus of Halley's comet. received by the vehicle "Vega-2" on March 9, 1986 from a distance of 8030 km ("Shoe")
The Japanese spacecraft passed at a relatively large distance from the comet (), "Vega" - approaching the comet at 8000 km and "Giotto" - at 600 km. While the Japanese experiment meant the study of the outer parts of the comet from a relatively close distance without interference from the earth's atmosphere, the other three spacecraft strove for the closest possible approach, in the case of Giotto, not without the risk of being damaged by dust masses. A total of 35 different experiments were carried out.
Vega and Giotto have registered the solid nucleus of Halley's comet. It is irregular in shape, rotates, and therefore all devices observed its different shape. In fig. 237 shows an image transmitted by Vega-2. The dimensions of the "shoe" are 24x16 km, the original shows separate outflows (emissions) of dust from this solid towards the Sun. "Vega-1" recorded a more regular shape, reminiscent of a 13X15 km plum, and, finally, according to Giotto's data, the core has a size of 15x7-10 km.
The last result deserves the greatest confidence, since it was obtained from the shortest distance. Giotto's core also looks like a shoe when viewed from the unlit side. In the "Giotto" experiment, the albedo of the surface of the nucleus is very small, 2-4%, depending on the angle of view. This confirms the model of the core as a lump of dirty snow covered with stones and dust remaining from the melting of snow at a temperature of 300-400 K and its removal by sublimation into gases. The nucleus of Halley's comet rotates with a period of about.
Rice. 238. Photo of Halley's comet. taken by the 124-centimeter Schmidt telescope at the Anglo-Australian Observatory on February 22, 1986 - shortly after the comet passed perihelion. North is up, east is on the left. Frame dimensions 2 ° X2 °
Rice. 239. 30-minute photograph of Halley's comet taken on March 10, 1986 with the 1-meter Schmidt telescope at the European Southern Observatory. North is on the left, west is on top. The bar on the right shows the dimensions of a half-degree. The entire length of the comet's tail these days exceeded 10 °
The gases that make up the comet's head and tail, as well as dust, have undergone conventional spectral analysis and mass spectroscopy. It turned out that the main substance is water, which is ejected from the core at a speed of about (or). Subsequently, water dissociates into H and OH with possible ionization after that. The second most abundant is carbon dioxide. Dust grains with mass are common. The more massive ones at large distances from the nucleus are less numerous. The top of the comet's head paraboloid, facing the Sun, is located at a distance of 4000-45000 km from the nucleus. This is where particles are thrown from the core towards the Sun before being picked up by the oncoming solar wind. The comet head carries a magnetic field with an intensity that changes during flight.
Ground-based observations of Halley's comet also brought a lot of interesting things. Celestial mechanics managed to give an accurate ephemeris of the comet after its seventy years of wandering in distant spaces of the solar system, and the comet was discovered already in October 1982, that is, more than three years before it passed through perihelion. It was at this time at a distance of 11 astronomical units from the Sun and looked like a stellar object. Only at the end of 1984 did Halley's comet become available to medium-sized telescopes, but only in 1985 its observations became massive. After passing perihelion on February 9, 1986, it then left the close vicinity of the Sun and showed a variety of continuously changing forms, mainly of the tail, the length of which was visually estimated at 10 °. The comet at that time was located in the southern sky and was accessible only to a few of the southernmost observatories of the northern hemisphere in March and only to observatories of the southern hemisphere in April, when it had already retired from the Sun by 1.3 AU. e. (against 0.6 AU at perihelion) and descended to a parallel of -45 ° in the southern sky. Rice. 238 and 239 show the comet in February and March 1986.
> Halley
Halley's comet, captured in 1986
- comet of the Solar system: period of revolution, photo, history of research, year of Halley's comet, eccentricity, when it arrives, semi-major axis.
Halley's comet is a short-period comet that arrives on our planet every 75 years. We last saw her in 1986. If you are wondering when it will arrive back, then the Earth is expecting its return in 2061.
The comet was named after Edmund Halley, who examined its arrival in 1531, 1607 and 1682. He realized that all three comets are the only returning object. So he was able to predict that 1758 should be taken as the year of Halley's comet.
Halley did not live to see this point, but his conclusions were correct. Moreover, his calculations showed that a certain category of comets is constantly returning to Earth. In 1986, terrestrial telescopes monitored the arrival of Halley's comet, and some spacecraft even planned to take samples.
It is difficult to observe because the period of Halley's comet spans tens of years. Therefore, scientists concentrate on other objects in order to compare and deduce the characteristics of the class. For example, the analysis of 67P / Churyumov-Gerasimenko showed that water on comets differs in composition from that on Earth.
The history of Halley's comet
The first record of a comet was left in 239 BC. e. Listed in the Chinese chronicles 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 you to study its orbital path in the past.
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 speaks of the arrival of a new object. They were often seen as messengers of catastrophes. This is also noticeable in Shakespeare's play Julius Caesar, where one of the lines says that comets mark the death of kings.
Discovery of the periodicity of Halley's comet
Even during Shakespeare's lifetime, astronomers tended to believe that the sun was at the center of the solar system. It took many years until a whole powerful concept was established, forcing us to take a fresh look at our place in the Universe (the heliocentric system).
In 1705, Edmund Halley finished studying 24 comets and published the Astronomical Summary of Comets, where he noted the objects that arrived in the years 1337-1698. Three of them coincided in orbits and other parameters, and he assumed that it was 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 approached us by 22.4 million km. It was in this year that we received her first photo. It's amazing that Mark Twain accurately predicted his death. He wrote that he arrived with a comet in 1835 and will leave on the next arrival. It happened on April 21, 1910.
Space age
In 1986, mankind was able to use spaceships for the first time in research. And it was a good moment, because she came close to the planet. Several vehicles called "Halley's Armada" went to the comet. The Soviet-French mission Vega-1 and 2 went to the facility and one even managed to capture the core. Two probes also flew from Japan.
Photos of Halley's comet also came from NASA's International Cometary Explorer, which has been in operation since 1978. Photos were taken at a distance of 28 million km.
The arrival of the comet also marked a tragic event. The crew of the STS-51L Challenger planned to follow her. But on January 28, the ship exploded on takeoff and 7 astronauts were killed.
Until the re-arrival to wait for another tens of years, but we can monitor the cosmic remnants in space. We are talking about the Orionids meteor shower in October.
In 2061, Halley's comet will be located on the same side of the Sun as the Earth and will be much brighter. Scientists believe that its periodicity is still dubious, because collisions with any object will repel it for thousands of years.
According to the prediction, its brightness should reach an apparent magnitude of -0.3. There are also objects that are part of the "comets of the Halley family". They converge in orbital characteristics. But there are also inconsistencies, which means they may have a different origin. Perhaps these are members of the Oort cloud or created from the centaurs (between Jupiter and the Kuiper belt).
Scientists do not sit idly by waiting for the comet. In 2014-2016. we had the amazing opportunity to visit comet 67P / Churyumov-Gerasimenko and analyze the samples. In the same way, the researchers studied 81P / Wild and 9P / Tempel.
Photos of Halley's comet
Halley's comet 1986
Comet in the Observatory of Mesa Observatory
On January 13, 1986, James Young captured a photo of Halley's comet from the Table Mountain Observatory using a 24-inch reflective telescope. The stripes created in the exposition are stars in the territory of Aquarius. The image shows a coma and a charged ion tail stretching for 725,000 km.
A comet in 1910
Comet seen by Giotto
On March 13, 1986, the multicolor camera of the Giotto apparatus recorded a cometary nucleus at a distance of 600 km.
Halley's Comet at Diamond Mountain
Halley's comet could be captured
Halley's comet viewed from Mount Wilson
| Discoverer: | It was observed in ancient times; named after Edmund Halley, who discovered the frequency of appearance |
| Opening date: | 1758 (first predicted perihelion) |
| Alternative designations: | |
| Orbit characteristics | |
|---|---|
| Eccentricity | 0,9671429 |
| Semi-major axis | 2.66795 billion km (17.83414 a.u.) |
| Perihelion | 87.661 million km (0.585978 a.u.) |
| Aphelion | 5.24824 billion km (35.082302 a.u.) |
| Period of circulation | 75.3 g |
| Orbit 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 |
The comets of the solar system have always been of interest to space explorers. The question of what these phenomena are, worries people who are far from studying comets. Let's try to figure out what this celestial body looks like, whether it can affect the life of our planet.
The content of the article:
A comet is a celestial body formed in Space, the dimensions of which reach the scale of a small settlement. The composition of comets (cold gases, dust and debris) makes this phenomenon truly unique. The comet's tail leaves a trail that is estimated at millions of kilometers. This spectacle bewitches with its grandeur and leaves more questions than answers.
The concept of a comet as an element of the solar system
To understand this concept, one should start from the orbits of comets. Quite a few of these cosmic bodies pass through the solar system.
Let's consider in detail the features of comets:
- Comets are so-called snowballs that pass through their orbit and contain dusty, rocky and gaseous clusters.
- The heating of a celestial body occurs during the period of approach to the main star of the solar system.
- Comets do not have satellites that are characteristic of planets.
- Formation systems in the form of rings are also not typical for comets.
- It is difficult and sometimes unrealistic to determine the size of these celestial bodies.
- Comets don't support life. However, their composition can serve as a certain building material.
Features of the structure of comets
The description of the comet can be divided into the characteristics of the nucleus, coma and tail of the object. This suggests that the studied celestial body cannot be called a simple construction.
Comet nucleus
Almost all of the comet's mass is contained in the nucleus, which is the most difficult object to study. The reason is that the core is hidden even from the most powerful telescopes by the matter of the luminous plane.
There are 3 theories that consider the structure of the comet nucleus in different ways:
- The dirty snow theory... This assumption is the most widespread and belongs to the American scientist Fred Lawrence Whipple. According to this theory, the solid part of the comet is nothing more than a combination of ice and fragments of meteorite composition. According to this specialist, old comets and bodies of a younger formation are distinguished. Their structure is different due to the fact that more mature celestial bodies repeatedly approached the Sun, which melted their original composition.
- The core is made of dusty material... The theory was voiced at the beginning of the 21st century thanks to the study of the phenomenon by the American space station. This intelligence suggests that the core is a very loose dusty material with pores occupying most of its surface.
- The kernel cannot be a monolithic structure... Further, the hypotheses diverge: they imply a structure in the form of a snow swarm, blocks of stone-ice accumulations and a meteorite heap due to the influence of planetary gravitations.
Comet coma
Together with the nucleus, the head of the comet forms a coma, which is a hazy shell of light color. The trail of such a component of the comet stretches for a rather long distance: from one hundred thousand to almost one and a half million kilometers from the base of the object.
Three levels of coma can be identified, which look like this:
- Interior chemical, molecular and photochemical composition... Its structure is determined by the fact that in this area the main changes occurring with the comet are concentrated and most active. Chemical reactions, decay and ionization of neutrally charged particles - all this characterizes the processes that take place in the inner coma.
- Coma of radicals... Consists of molecules active in their chemical nature. In this area, there is no increased activity of substances, which is so characteristic of an internal coma. However, here, too, the process of decay and excitation of the described molecules continues in a quieter and smoother regime.
- Coma of atomic composition... It is also called ultraviolet. This region of the comet's atmosphere is observed in the Lyman-alpha hydrogen line in the distant ultraviolet spectral region.
Comet tail
The comet's tail is a spectacle unique in its beauty and showiness. Usually it is directed from the Sun and looks like an elongated gas-dust plume. Such tails do not have clear boundaries, and we can say that their color gamut is close to full transparency.
Fedor Bredikhin proposed to classify sparkling trains according to the following subspecies:
- Straight and narrow tails... These components of the comet are directed from the main star of the solar system.
- Slightly deformed and wide-angle tails... These plumes deflect from the Sun.
- Short and highly deformed tails... This change is caused by a significant deviation from the main luminary of our system.
- Dust tail... A distinctive visual feature of this element is that its glow has a characteristic reddish tint. A train of this format is homogeneous in structure, stretching for a million, or even tens of millions of kilometers. It was formed due to the numerous grains of dust, which the energy of the Sun has thrown over a long distance. The yellow tint of the tail is due to the scattering of dust particles by sunlight.
- Plasma structure tail... This plume is much more extensive than the dust plume, because its length is calculated in tens, and sometimes hundreds of millions of kilometers. The comet interacts with the solar wind, from which a similar phenomenon occurs. As you know, solar vortex flows are penetrated by a large number of fields of the magnetic nature of the formation. They, in turn, collide with the comet's plasma, which leads to the creation of a pair of regions with diametrically different polarities. From time to time there is a spectacular break of this tail and the formation of a new one, which looks very impressive.
- Anti-tail... It appears according to a different scheme. The reason is that it is directed towards the sunny side. The influence of the solar wind on such a phenomenon is extremely small, because the plume contains large dust particles. It is realistic to observe such an anti-tail only when the Earth crosses the comet's orbital plane. The disc-shaped formation surrounds the celestial body from almost all sides.
The main types of comets
The types of comets can be distinguished by the time of their revolution around the Sun:
- Short-period comets... The orbital time of such a comet does not exceed 200 years. At the maximum distance from the Sun, they have no tails, but only a barely perceptible coma. With a periodic approach to the main luminary, a trail appears. More than four hundred such comets have been recorded, among which there are short-period celestial bodies with a term of 3-10 years around the Sun.
- Comets with a long orbital period... The Oort cloud, according to scientists, periodically supplies such space guests. The orbital term of these phenomena exceeds the mark of two hundred years, which makes the study of such objects more problematic. Two hundred and fifty such aliens give reason to assert that in fact there are millions of them. Not all of them are so close to the main star of the system that it becomes possible to observe their activities.
The most famous comets of the solar system
There are a large number of comets that pass through the solar system. But there are the most famous cosmic bodies that are worth talking about.
Halley's comet
Halley's comet became famous thanks to the observations of it by the famous explorer, after whom it got its name. It can be attributed to short-period bodies, because its return to the main luminary is calculated for a period of 75 years. It is worth noting the change in this indicator towards parameters that fluctuate within 74-79 years. Its celebrity lies in the fact that it is the first celestial body of this type, the orbit of which it was possible to calculate.
Certainly, some long-period comets are more spectacular, but 1P / Halley can be observed even with the naked eye. This factor makes this phenomenon unique and popular. Almost thirty recorded appearances of this comet delighted outside observers. Their frequency directly depends on the gravitational influence of large planets on the life of the described object.
The speed of Halley's comet in relation to our planet is striking, because it exceeds all indicators of the activity of the celestial bodies of the solar system. The approach of the Earth's orbital system with the orbit of the comet can be observed at two points. This leads to two dusty formations, which in turn form meteor showers called Aquarids and Oreanids.
If we consider the structure of such a body, then it is not much different from other comets. When approaching the Sun, the formation of a sparkling plume is observed. The comet's nucleus is relatively small, which may indicate a pile of debris in the form of building material for the base of the object.
It will be possible to enjoy the extraordinary spectacle of the passage of Halley's comet in the summer of 2061. Better visibility of the grand phenomenon is promised compared to the more than modest visit in 1986.
This is a fairly new discovery, which was made in July 1995. Two Space Explorers discovered this comet. Moreover, these scientists conducted separate searches from each other. There are many different opinions regarding the described body, but experts agree on the version that it is one of the brightest comets of the last century.
The phenomenal nature of this discovery lies in the fact that at the end of the 90s, the comet was observed without special devices for ten months, which in itself cannot but surprise.
The shell of the solid core of a celestial body is rather heterogeneous. Ice-covered areas of unmixed gases are combined with carbon oxide and other natural elements. The discovery of minerals that are characteristic of the structure of the earth's crust, and some meteorite formations, once again confirm that Comet Hale-Bop originated within our system.
The influence of comets on the life of the planet Earth
There are many hypotheses and assumptions regarding this relationship. There are some comparisons that are sensational.
Icelandic volcano Eyjafjallajokull began its active and destructive two-year activity, which surprised many scientists of that time. This happened almost immediately after the famous emperor Bonaparte saw the comet. This may be a coincidence, but there are other factors that make you wonder.
The previously described Halley's comet strangely influenced the activity of such volcanoes as Ruiz (Columbia), Taal (Philippines), Katmai (Alaska). The impact of this comet was felt by the people living near the Cosswin volcano (Nicaragua), which began one of the most destructive activities of the millennium.
Comet Encke caused the most powerful eruption of the Krakatoa volcano. All this may depend on solar activity and the activity of comets, which provoke some nuclear reactions as they approach our planet.
Falling comets are rare. However, some experts believe that the Tunguska meteorite belongs to just such bodies. They cite the following facts as arguments:
- A couple of days before the catastrophe, the appearance of dawns was observed, which, with their variegation, testified to anomality.
- The appearance of such a phenomenon as white nights, in places unusual for it, immediately after the fall of a celestial body.
- The absence of such an indicator of meteoriticity as the presence of a solid substance of this configuration.
What a comet looks like - watch the video:
The comets of the solar system is a fascinating topic that requires further study. Scientists all over the world, engaged in the study of the Cosmos, are trying to unravel the secrets that these celestial bodies of amazing beauty and power carry.
In 2009, Robert McNaught opened comet C / 2009 R1, which is approaching the Earth, and in mid-June 2010 the inhabitants of the northern hemisphere will be able to see it with the naked eye.
Comet Morehouse(C / 1908 R1) is a comet discovered in the USA in 1908, which was the first comet to be actively studied using photography. There were surprising changes in the structure of the tail. During the day of September 30, 1908, these changes took place continuously. On October 1, the tail came off and could no longer be visually observed, although a photograph taken on October 2 showed the presence of three tails. The rupture and subsequent growth of the tails occurred repeatedly.
Comet Tebbutta(C / 1861 J1) - a bright comet visible to the naked eye, was discovered by an Australian amateur astronomer in 1861. Earth passed through the comet's tail on June 30, 1861.
Comet hyakutake(C / 1996 B2) is a large comet that reached zero brightness in March 1996 and formed a tail that is estimated to be at least 7 degrees in extent. Its apparent brightness is largely due to its proximity to Earth - the comet passed from it at a distance of less than 15 million km. The maximum approach to the Sun is 0.23 AU, and its diameter is about 5 km.
Humason's comet(C / 1961 R1) - a giant comet, discovered in 1961. Its tails, despite such a great distance from the Sun, still extend 5 AU in length, which is an example of unusually high activity.
Comet McNaught(C / 2006 P1), also known as the Big Comet of 2007, is a long-period comet discovered on August 7, 2006 by British-Australian astronomer Robert McNaught, and has become the brightest comet in 40 years. Inhabitants of the northern hemisphere could easily observe it with the naked eye in January and February 2007. In January 2007, the comet's magnitude reached -6.0; the comet was visible everywhere in daylight, and the maximum tail length was 35 degrees.
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