Considering the sky at night, it is possible to see visually static flickering lights, that is, the stars endowed with permanent orbits and the gravitational field. They are opposed to comet, asteroid, meteorite and other celestial objects in constant motion and moving along a specific trajectory. What they differ and what characteristics do it - in the material 24cm.
The comet is different from the asteroid
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Despite the possible external similarity, asteroids and comets differ from each other for a number of factors:
- The priority difference is the difference between the compositions of the considered bodies of the solar system. The asteroid consists of a metal and rocky substance, and a comet of dust and ice, occasionally including rocky rocks. At the same time, representatives of both species of extraterrestrial objects were formed at the initial stage of the solar system's origin - approximately 4-4.5 billion years ago.
- Next, it is necessary to say that comets have formed further from the Sun, which allowed them to include ice, and asteroids - an order closer.
- The presence of a tail: the comet has it, and the asteroid is missing.
- The size of the orbits comet is more than that of asteroids, in addition to this, the last of the space bodies under consideration "strive" to unite into the belt.
Turning to the description of the structure of an extraterrestrial object, it is required to note that one of the parts of the comet is a coma, a foggy bunch, an enveloping kernel and is a mixture of dust and gas, as well as stretching from 150 thousand to 1.3 million km from the nucleus.
What is the nucleus of comet
The main part of the observed celestial object is the kernel, the dominant part of the mass of the cosmic body is concentrated in it. According to the American astronomer Freda Loorens Wipple, nominated by him in the 1930s, the model of the comet's kernel is a mixture of ice with a grain of meteorous matter.After the study, the Deep Impact, owned by the United States and sent on an extraterrestrial object Tempel 1, in 2005 it became clear that in reality the core is a loose material, which is dust with the pores that occupy 4/5 of its volume.
Why the tail of the comet always directed away from the sun
Coma and tail are less than 0.01% of the mass of the comet, but it is due to them that it produces 99.9% of the bright luminescence emitted by an extraterrestrial object at the expense of the gases contained in these parts. The tails of the extraterrestrial bodies under consideration are a mixture of dust and gases, and also extend hundreds of millions of kilometers and possess a structure that transmits the light through which the stars can be seen.
The reason why the tail of the heavenly body is directed against the Sun is in the action of solar wind, "blowing" gases in the tail part of the space object. However, this wind is not something that is usually understood under this phenomenon. Sunny wind is a composition of protons, electrons and other elementary particles. Its action leads to the fact that the comet's ice particles leave its surface, subsequently stretching over millions of kilometers.
Study history
In antiquity, people with cautiousness and fear treated the emergence of extraterrestrial bodies, tying these phenomena with impending difficulties and troubles.
During the revival of Astronomer from Denmark, Tycho Brage, at the expense of his studies, Comet transferred to the status of space objects, while his colleague Lagrange two centuries later suggested that the celestial bodies under consideration were formed after the explosions that occurred on other planets. Laplace adhered to the opinion of the origin of comet from interstellar expanses.
In the interval between the 1680-1681 years, the young gallow contemplated in the sky a bright extraterrestrial body approaching to the Sun, and then distinguished from him, - this circumstance made him explore the phenomenon in more detail, since the event created a number of contradictions in the presentation of its rectilinear movement.
Subsequently, after a number of studies and discussions, including Newton, Galley has created a book of orbit elements and made the assumption that extraterrestrial bodies, beyond which he observed, in reality are the same space object with a period of circulation around the Sun 74-76 years . In 1758, Hallery's hypothesis was confirmed - an extraterrestrial body was named after him after flewing near the earth exactly at that time, which was indicated by an astronomer.
A full understanding of what the overwhelmed cosmic bodies are represented in 1986, when Comet Halley became the first extraterrestrial object to which spacecraft, BERA-1 and BERA-2 went. Thanks to the numerous sensors installed on them, scientists received images and information about the composition of the shell, also it turned out that the kernel is the usual ice with splashes of dust particles.
From the biggest to the smallest
More than 6 thousand comets were detected by astronomers, the most famous and remarkable ones are below:- The most famous of the existing extraterrestrial objects is the Gallet Comet. For the first time it was noticed in 239 BC. NS. - She flew over the Earth 30 times, and as close as possible to the planet in 837. The next time an extraterrestrial body will become visible from the ground in 2061.
- Comet Lexel - is called the closest to our planet and flies 2-2.2 million km from it. Its discovery belongs to the chalp Messier - the event occurred in the 1770s, but the space facility was named in honor of Andrei Lexel, who studied her orbit and subsequently published the results of his works in 1772-1779.
- Heavenly object found in 1900 by Jacobani, and then in 1913 by his colleague astronomer Zinner. The comet time around the Sun is 6.5 years, and the diameter is 6 km. The cosmic body is associated with the meteoric flow of a draconide occurring in October and formed after entering the land of the Earth of the fragments of the celestial object under consideration moving along the same orbit.
- One of the brightest extraterrestrial bodies is the so-called. Comet Swazo. It was opened in 1743, and its star magnitude is -7, in addition to this, a lot of branched tailings was found at the cosmic body.
- MacNacta comet, referred to as the "big", was recorded in 2006 by Astronomer Robert Maknot and subsequently named the brightest extraterrestrial body over the past 40 years. Her presence was easily viewed in the northern hemisphere in 2007, even during the daytime.
- Comet Churyumova-Gerasimenko - Opened by astronomer from the USSR in October 1969 after Svetlana Gerasimenko's photoflands was noticed, shot in September of the same year (in originally another space object was originally). The cosmic body is noteworthy in that the specific shape of its kernel is supposedly formed after the collision of the other two comets.
- The smallest celestial bodies include a small comet Hartley 2 with a length of 2.2 km and weighing 280 million tons. The fifth time in the history of mankind Space apparatus from the US Dip Impact managed to capture the comet's core near - this happened in November 2010.
- The largest among famous is the Bernardine-Bernstein comet width of 100-200 km. The heavenly body is located in the Oort cloud, located in the same light year from the Sun and will be near him in 2031, and also named after two astronomers from the university in Pennsylvania.
New comets
Annually, the Astronomer Community reveals new extraterrestrial bodies, the last of them are presented below:
- Comet C / 2020 F3 - fixed in March 2020 by means of the NeoWise telescope. Scientists assumed that the heart, or the core, the cosmic body will not survive rapprochement with the Sun and split, but it turned out otherwise - the comet managed to overcome the critical intimacy with the main luminaire, after which it began to move away from him by gaining brightness. It was observed with the naked eye in July 2020, for example, in St. Petersburg, the next time the wonderful spectacle will be able to see only after 6,800 years.
- The first cosmic body, open by astronomers in 2021, promises to become the brightest comet of this year. In November-December, Comet C / 2021 A1 (Leonard) approaches Earth so much that it will be possible to consider without special devices, only turning his eyes on the sky. Also, the Space body will be 4 million km from Venus - before that, only 5 events were recorded when an extraterrestrial object was in similar intimacy from the Earth.
Guest from Far Cosmos
Gennady Borisov, an astronomer of the amateur from Crimea, in the summer of 2019 he fell into the Guinness Book of Records, discovering the first in the history of mankind of interstellar comet. In the spring of the same year, the core of the far cosmic body was destroyed, shortly after that, an extraterrestrial object left the solar system, returning to interstellar expanses. Already in 2020, Borisov made an anniversary discovery, discovering with the help of a homemade telescope 10th comet C2020 Q1 Borisov. As in previous cases, it was called in his honor.
What will happen if the comet falls to the ground?
The size and mass of comets are extremely small, hundreds of millions of times less than the Earth, as a result of which they almost do not have any impact on the space bodies of the solar system. Moreover, sometimes our planet passes through the comets, for example, as happened in 1910, the year, the Earth passed through the tail part of the Gallea comet, not subject to any changes.
At the same time, if possible, the atmosphere and magnetosphere of our planet can seriously suffer from a possible collision with the observed celestial body. According to the view of Astrophysics from the US, Lisa Randall, from time to time, the Earth faced with mass extinctions occurring in the Biosphere of the Planet after a collision with extraterrestrial representatives from the Oort cloud.
One of the most global mass extinction is the death of dinosaurs, which happened 60-65 million years ago, presumably, after impact events - the falls of a large meteorite, asteroid, comets, or other extraterrestrial objects to Earth.
Comets and other cosmic bodies are periodically flying at a distance, allowing you to see them from the planet with the naked eye. There are also cases of valid incidence of extraterrestrial objects on the surface of the Earth - for example, when in 1908 in Eastern Siberia, presumably, a Tungusian meteorite fell. Given the said, reasonably express anxious about the fact that in the future, humanity may have to face an obvious danger in the face of an extraterrestrial guest called "Comet". Or any other object that in the case of a "successful" flight path will cause irreparable damage to the planet, repeating something similar to mass extinction.