Since ancient times, people have sought to uncover the secrets that are fraught with the sky. Since the first telescope was created, scientists have been gradually collecting 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 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 contain water, as well as gases such as methane, ammonia, and carbon dioxide. The Churyumov-Gerasimenko comet, discovered on October 23, 1969, has the same structure.
How the comet was previously represented
In ancient times, our ancestors revered 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.shower. Where did this panicky fear come from? Perhaps the whole point is that the appearance of these heavenly creatures ever coincided with some unkind incident.
However, as time went on, the idea of what small and large comets were changed. For example, such a scientist as Aristotle, investigating 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 moving in their orbits. However, it was only after the creation of the telescope that real progress in their study was made. 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 is the nucleus of a comet made of? From a mixture of frozen water and space dust. In 1986, pictures of one of the comets were taken. It became clear that its fiery tail is an ejection of a stream of gas and dust, which we can observe from the earth's surface. What is the reason for this "fiery" release? If an asteroid flies very close to the Sun, then its surface heats up, which leads to the release of dust and gas. Solar energy puts pressure on the solid material that makes up the comet. As a result, a fiery tail of dust is formed. This debris and dust is part of the trail that we see in the sky when we observe the movement of comets.
What determines the shape of the comet tail
The comet report below will help you better understand whatwhat are comets and how they are arranged. They are different - with tails of various shapes. 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, and 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, while the latter are 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 can be said about the density of a comet's tail? Usually 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 mostly of rarefied particles, having almost no density. As an asteroid approaches the Sun, the comet's tail can split in two and become complex.
The velocity of particles in a comet tail
Measuring the speed of movement in the tail of a comet is not so easy, since we cannot see individual particles. However, there are cases when the velocity of matter in the tail can be determined. Sometimes gas clouds can condense there. From 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 greater than the gravity of the Sun.
How much does it weighcomet
The entire mass of comets is largely dependent on the weight of the comet's head, or rather, its nucleus. Supposedly, 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 Earth's orbit, leaving behind a trail of debris. When our planet passes over 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 the fragments of the comet burn up in the atmosphere, we see a beautiful trail. This phenomenon is called meteors (or meteorites).
Age of comets
Fresh huge asteroids can live in space for trillions of years. However, comets, like any cosmic bodies, cannot exist forever. The more often they approach the Sun, the more they lose the solid and gaseous substances that make up their composition. "Young" comets can drop in weight very much until a kind of protective crust forms on their surface, which prevents further evaporation and burnout. However, 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 body of the comet forward and forward, giving speed to this traveler.
Halley's Comet
Another comet, similar in structure to the cometChuryumova - Gerasimenko, this is an asteroid discovered by Edmund Halley. He realized that comets have long elliptical orbits in which they move with a large time interval. 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 through 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. At least 1000 comets have been 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 in their orbit, as well as the period from circulation. Taking Halley's Comet, mentioned earlier, as an example, it takes less than 200 years to complete one revolution around the sun. It belongs to periodic comets. However, there are those that cover the entire path in much shorter periods of time - the so-called short-period comets. We can be sure that in our solar system there are a huge number of periodic comets that orbit around our star. Such celestial bodies can move so far from the center of our system that they leave behind Uranus, Neptune and Pluto. Sometimes they can get very close to the planets, because of which their orbits change. Comet Encke is an example.
Information about comets:long-term
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 last approached our planet. Scientists have calculated that the next time from Earth they can be seen only after thousands of years. A lot of comets, with a long period of movement, 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 cometary 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 movement of some of these comets can be several light years. In this case, the comet will cover its entire path in 10,000,000 years!
Fragments of Comet Shoemaker-Levi 9
Reports of comets from all over the world help in their study. A very interesting and impressive vision could be observed by astronomers in 1994. More than 20 fragments left from the comet Shoemaker-Levy 9 collided with Jupiter at a crazy speed (approximately 200,000 kilometers per hour). Asteroids flew into the planet's atmosphere with flashes and huge explosions. The incandescent gas influenced the formation of very large fiery spheres. The temperature to which the chemical elements warmed up was several times higher than the temperature that is recorded on the surface of the Sun. Afterwhich in telescopes one could see a very high column of gas. Its height has reached enormous proportions - 3200 kilometers.
Biela's Comet is a double comet
As we have already learned, there is plenty of evidence that comets break down over time. Because of this, they lose their brightness and beauty. We can consider only one example of such a case - Biela's comets. It was first discovered in 1772. However, subsequently 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 determined that a year ago the Biela asteroid split in two. The last time scientists recorded the appearance of this miracle comet. One part of it was much brighter than the other. She was never seen again. However, after a while, a meteor shower was more than once striking, the orbit of which exactly coincided with the orbit of Biela's comet. This case proved that comets can break apart 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 were knocked down. What would happen if such a block exploded over a large city,like 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 hit the Earth? As mentioned above, in mid-July 1994, the planet Jupiter was "shelled" by debris from 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
Information about comets known to scientists sows fear in their hearts. Astronomers and analysts draw terrible pictures in their minds with horror - a collision with a comet. When an asteroid flies into the atmosphere, it will cause irreversible destruction processes inside the cosmic body. It will explode with a deafening sound, and on Earth it will be possible to observe a column of meteorite fragments - dust and stones. The sky will be engulfed in a fiery red glow. There will be no vegetation left on Earth, as all forests, fields and meadows will be destroyed due to the explosion and fragments. Due to the fact that the atmosphere will become impervious to sunlight, it will become sharply cold, and plants will not be able to perform the role of photosynthesis. Thus, the nutrition cycles of marine life will be disrupted. Being without food for a long time, many of them will die. All of the above events will affect the natural cycles. Widespread acid rain will have a detrimental effect on 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 will be that these cataclysms will be muchon a larger scale than those that we could experience for ourselves over several thousand years of human history. Huge waves of hundreds or thousands of meters will sweep away everything in their path. There will be nothing left of towns 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, then this will only lead to sky lighting and meteor showers. Should we worry about the future of our planet? Is there a chance we will ever be met by a flying comet?
The fall of a comet. Should I be afraid
Can we trust everything 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 everything is thought out in its design. It is difficult for meteorites and comets to reach our planet because it is protected by a giant shield. The planet Jupiter, due to its size, has a huge gravity. Therefore, it often protects our Earth from asteroids and comet remnants flying by. The location of our planet leads many to believe that the whole device was thought out and designed in advance. And if so, and you are not a zealous atheist, then you cansleep well, because the Creator will undoubtedly preserve the Earth for the purpose for which he created it.
Names of the most famous
Comet reports from various scientists around the world form a huge database of information about cosmic bodies. Among the most famous, there are several. For example, comet Churyumov - Gerasimenko. In addition, in this article we could get acquainted with the comet Fumaker - Levy 9 and the comets Encke and Halley. In addition to them, Sadulaev's comet is known not only to researchers of the sky, but also to lovers. 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, just as it is impossible to embrace all the expanses of space, it will not be possible to describe or list all 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 expanses 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 into such expanses of space that thinking about its immensity and unknowability plunges one into awe. Many agree that all this could not have appeared by itself and without a purpose. Such a complex structure must have an intention. However, manyquestions related to the structure of the cosmos remain unanswered. It seems that the more we learn, the more reason to explore further. In fact, the more information we acquire, the more we realize that we do not know our solar system, our Galaxy, the Milky Way, and even more so the Universe. However, all this does not stop astronomers, and they continue to struggle further on the mysteries of life. Every nearby comet 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 encourages them to do so. 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 a search on the Internet. 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 the Churyumov-Gerasimenko comet. In order to find it, you must enter its serial number 67 R. If you are interested in another object, for example, Sadulaev's comet. Then you can try to enter its name in Latin or enter its special number. Through this program, youlearn more about space comets.
