Since ancient times, people have sought to uncover the secrets that the sky conceals. Since the first telescope was created, scientists began to collect step by step particles of knowledge that are hidden in the vast expanses of space. It's time to find out where the messengers from outer space came from - comets and meteorites.
What is a comet?
If we examine the meaning of the word "comet", then we come to its ancient Greek equivalent. Literally, it means "with long hair." Thus, the name was given in view of the structure of this celestial body. The comet has a “head” and a long “tail” - a kind of “hair”. The head of a comet consists of a nucleus and perinuclear substances. The loose core may include water, as well as gases such as methane, ammonia and carbon dioxide. The comet Churyumov - Gerasimenko, discovered on October 23, 1969, has the same structure.
How the comet was represented before
In ancient times, our ancestors reverence for her and invented various superstitions. Even now there are those who connect the appearance of comets with something ghostly and mysterious. Such people may think that they are wanderers from another world of souls. Where did such panic fear come from ? Perhaps the whole point is that the appearance of these celestial creatures has ever coincided with some unfortunate event.
However, time passed, and the idea of what small and large comets were was changing. For example, a scientist like Aristotle, exploring their nature, decided that it was a luminous gas. After a while, another philosopher named Seneca, who lived in Rome, suggested that comets are bodies in the sky that move in their orbits. However, to really progress in their study turned out only after the creation of the telescope. When Newton discovered the law of gravity, things went up.
Current ideas about comets
Today, scientists have already established that comets consist of a solid core (from 1 to 20 km in thickness). What does the comet's core consist of? From a mixture of frozen water and space dust. In 1986, pictures were taken of one of the comets. It became clear that her fiery tail is an emission of a stream of gas and dust, which we can observe from the earth's surface. What is the reason for this “fiery" outburst? If the asteroid flies very close to the Sun, then its surface is heated, which leads to the emission of dust and gas. Solar energy puts pressure on the solid material that the comet consists of. As a result of this, a tail of fire is formed from dust. These debris and dust are part of the trace that we see in the sky when we observe the movement of comets.
What determines the shape of the comet tail
The comet message below will help you better understand what comets are and how they are arranged. They are different - with tails of various shapes. It is 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 a star. What is the reason? It turns out that the former move, pushed away by solar energy, away, while the latter is affected by the gravitational force of the Sun. As a result of these physical laws, we get comets whose tails are curved in various ways. Those tails, which are mostly composed of gases, will be directed away from the star, and corpuscular (consisting mainly of dust), on the contrary, will tend to the Sun. What about the density of the comet's tail? Typically, cloud tails can be measured in millions of kilometers, in some cases hundreds of millions. This means that, unlike the body of a comet, its tail consists to a greater extent of discharged particles with practically no density. When an asteroid approaches the Sun, the tail of the comet can bifurcate and acquire a complex structure.
Particle Tail Velocity
It is not so easy to measure the speed of motion in the tail of a comet, since we cannot see individual particles. However, there are cases when the speed of the substance in the tail can be determined. Sometimes gas clouds can condense there. By their movement, you can calculate the approximate speed. So, the forces that move 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 is more dependent 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 behind it. When our planet passes at the place where the comet was, these debris and cosmic dust left from it enter the atmosphere with great speed. This speed reaches more than 70 kilometers per second. When fragments of a comet burn up in the atmosphere, we see a beautiful trace. This phenomenon is called meteors (or meteorites).
The age of comets
Fresh huge asteroids can live in space for trillions of years. However, comets, like any cosmic body, cannot exist forever. The more often they come closer to the Sun, the more they lose the solid and gaseous substances that make up their composition. "Young" comets can very strongly lose weight 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 losing its weight and size. Thus, the surface crust acquires many wrinkles, cracks and breaks. Gas flows, burning, push the comet's body on and on, giving speed to this traveler.
Comet Halley
Another comet, the structure is the same as Churyumov's comet - Gerasimenko, is an asteroid discovered by Edmund Halley. 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 one and the same comet, which moved along its trajectory after a period of time 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 near us. They are divided into two families, and they, in turn, are divided into classes. To classify comets, scientists take into account their features: the time during which they are able to go all the way in their orbit, as well as the period from circulation. If we take for example Halley's comet, mentioned earlier, then it undergoes a complete revolution around the sun in less than 200 years. It refers to periodic comets. However, there are those that travel all the way for much shorter periods of time - the so-called short-period comets. We can have no doubt that in our solar system there are a huge number of periodic comets whose orbits pass around our star. Such celestial bodies can be so far removed from the center of our system that they leave behind Uranus, Neptune and Pluto. Sometimes they can come very close to planets, because of which their orbits change. As an example, comet Enke.
Comet Information: Long-Period
The trajectory of long-period comets is very different from short-period comets. They go around the sun from all sides. For example, Heyakutake and Hale-Bopp. The latter looked very spectacular when they were approaching our planet for the last time. Scientists have calculated that the next time they can be seen from Earth only after thousands of years. A lot of comets with a long period of movement can be found on the edge of our solar system. As far back as the middle of the 20th century, the 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 in the Oort Cloud? According to some assumptions, not less than a trillion. The period of motion of some of these comets can be several light years. In this case, the comet will overcome its entire path in 10,000,000 years!
Fragments of Comet Shoemaker - Levy 9
Reports of comets from around the world help in their research. Astronomers could observe a very interesting and impressive vision in 1994. More than 20 fragments left from the comet Shoemaker - Levy 9 with a crazy speed (approximately 200,000 kilometers per hour) collided with Jupiter. Asteroids flew into the atmosphere of the planet with flashes and huge explosions. The hot gas affected the formation of very large fire spheres. The temperature to which the chemical elements warmed up was several times higher than the temperature that is fixed on the surface of the sun. After that, a very high column of gas could be seen in the telescopes. Its height has reached enormous size - 3200 kilometers.
Comet Biela - Double Comet
As we already learned, there is plenty of evidence that comets collapse over time. Because of this, they lose their brightness and beauty. You can consider only one example of such a case - comets Biela. The first time it was discovered in 1772. However, later it was repeatedly noticed 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 whole comets that went next to each other. What happened? Astronomers have determined that a year ago, Biel’s asteroid split in two. The last time scientists recorded the appearance of this miraculous comet. One part of it was much brighter than the other. She was never seen again. However, over time, a meteorite shower, the orbit of which exactly coincided with the orbit of the comet Biela, was more than once evident. This case proved that comets are capable of decaying over time.
What happens in a collision
For our planet, a meeting with these celestial bodies does not bode well. A large fragment of a 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 fell. What would happen if such a block burst above a large city such as New York or Moscow? It would cost the lives of millions of people. And what would happen if a comet with a diameter of several kilometers fell into the Earth? As mentioned above, in mid-July 1994, the planet Jupiter was "bombarded" with the wreckage of comet Shoemaker - Levy 9. Millions of scientists watched what was happening. How would such a collision end up for our planet?
Comets and Earth - representations of scientists
Information about comets, known to scientists, sows fear in their hearts. Astronomers and analysts are horrified to paint terrible pictures in their minds - a collision with a comet. When an asteroid flies into the atmosphere, it will cause irreversible processes of destruction inside the cosmic 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. A fiery red glow envelops the sky. There will not be any vegetation on Earth, because due to the explosion and fragments all forests, fields and meadows will be destroyed. Due to the fact that the atmosphere will become impervious to sunlight, it will suddenly become cold, and plants will not be able to play the role of photosynthesis. Thus, the nutritional cycles of marine inhabitants are disrupted. Being without food for a long time, many of them will die. All of the above events will affect the natural cycles. Ubiquitous acid rain adversely affects the ozone layer, so it will become impossible to breathe on our planet. What happens if a comet falls into one of the oceans? Then this can lead to disastrous environmental disasters: the formation of tornadoes and tsunamis. The only difference is that these cataclysms will be much larger than those that we could feel on ourselves for several thousand years of human history. Huge waves of hundreds or thousands of meters will sweep away everything in its path. From the towns and cities there will be nothing left.
"Do not worry"
Other scientists, on the contrary, say that there is no need to worry about such disasters. According to them, if the Earth comes close to a celestial asteroid, it will only lead to lighting the sky and meteor shower. Is it worth worrying about the future of our planet? Is there any chance that a flying comet will ever meet us?
The fall of the comet. Is it worth it to be afraid
Can you trust everything that scientists represent? Do not forget that all the information about comets recorded above is 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 explore our solar system admire how well thought out everything is in its structure. It is difficult for meteorites and comets to reach our planet, since it is protected by a giant shield. The planet Jupiter, in view of its size, has enormous gravity. Therefore, it often protects our Earth from flying past asteroids and the remnants of comets. The place in which our planet is located makes many think that the whole 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
Communication about comets from various scientists from around the world make up a huge database of information about cosmic bodies. Among the particularly well-known, there are several. For example, comet Churyumov - Gerasimenko. In addition, in this article we could get acquainted with the comet Foemaker - Levy 9 and comets Enke and Halley. In addition to them, it is known not only to sky researchers, but also to fans of Comet Sadulayev. In this article we tried to provide the most complete and verified information about comets, their structure and contact with other celestial bodies. However, just as it is impossible to capture all the open spaces of the cosmos, it will not be possible to describe or list all the currently known comets. Brief information about the comets of the solar system is presented in the illustration below.
Sky studies
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 the tireless desire of man to explore the vastness of space will continue to push him to try to understand the structure of celestial bodies: meteorites, comets, asteroids, planets, stars and other more powerful objects. Now we have penetrated such open spaces of space that thinking about its immensity and unknowability thrills. Many agree that all this could not appear on its own and without purpose. Such a complex design must have an intention. However, many questions related to the structure of the cosmos remain unanswered. It seems that the more we learn, the more reasons there is to explore further. In fact, the more information we acquire, the more we realize that we poorly know our solar system, our galaxy, the Milky Way, and especially the Universe. However, all this does not stop astronomers, and they continue to continue to fight over 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 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 for free using the 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 built-in oriented search in the system. For example, you need the 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, Comet Sadulayev. Then you can try to enter its name in Latin letters or enter its special number. Thanks to this program, you can learn more about space comets.