Astronomy is a science that studiescelestial objects. Considers stars, comets, planets, galaxies, also does not neglect existing phenomena occurring outside the Earth’s atmosphere, for example, cosmic radiation.
Studying astronomy, you can get an answer to the question “Heavenly bodies that glow themselves. What it is?".
Solar system bodies
To find out whether there are celestial bodies that glow themselves, you first need to understand what kind of celestial bodies the solar system consists of.
The solar system is a planetary system, inthe center of which is a star - the Sun, and around it there are 8 planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. To call a celestial body a planet, it must meet the following requirements:
- Make rotational motion around the star.
- Have a form in the form of a sphere, due to sufficient gravity.
- Not have other large bodies around its orbit.
- Do not be a star.
Planets do not emit light, they can onlyreflect the rays of the sun falling on them. Therefore, it cannot be said that the planets are celestial bodies that glow themselves. These celestial bodies are stars.
The sun is the source of light on Earth
The heavenly bodies that glow themselves are the stars.The closest star to Earth is the Sun. Thanks to its light and warmth, all living things can exist and develop. The sun is the center around which the planets, their satellites, asteroids, comets, meteorites and cosmic dust rotate.
The sun seems to be a solid spherical object,because when you look at it, its outlines look quite clear. However, it does not have a solid structure and consists of gases, the main one being hydrogen, and other elements are also present.
To see that the sun has no clearcontours, it is necessary to look at it during an eclipse. Then you can see that it is surrounded by a moving atmosphere, which is several times larger than its diameter. In normal light, this halo is not visible due to bright light. Thus, the Sun has no exact boundaries and is in a gaseous state.
Stars
The number of existing stars is unknown, they are located at a great distance from the Earth and are visible as small dots. Stars are celestial bodies that glow themselves. What does this mean?
Stars - hot balls, consisting of gas, inwhich occur thermonuclear reactions. Their surfaces have different temperature and density. The size of the stars also differ among themselves, while they are larger and more massive than the planets. There are stars whose dimensions exceed the size of the Sun, and there are vice versa.
Звезда состоит из газа, в большей мере – водорода.On its surface, from high temperature, the hydrogen molecule breaks down into two atoms. An atom consists of a proton and an electron. However, the atoms under the influence of high temperatures "release" their electrons, the result is a gas called plasma. An atom left without an electron is called a nucleus.
How stars emit light
The star, due to gravitational force, triessqueeze itself, with the result that in the central part of the temperature rises. Nuclear reactions begin to occur, resulting in helium with a new nucleus, which consists of two protons and two neutrons. As a result of the formation of a new nucleus, a large amount of energy is released. Particles-photons are released as an excess of energy, and they also carry light. This light exerts a strong pressure that emanates from the center of the star, resulting in an equilibrium between the outgoing pressure from the center and the gravitational force.
So the celestial bodies that glowthemselves, namely the stars shine due to the release of energy during nuclear reactions. This energy is aimed at containing gravitational forces and at emitting light. The more massive the star, the more energy is released and the brighter the star shines.
Comets
A comet consists of an ice clot in whichthere are gases, dust. Its core does not emit light, but when approaching the Sun, the core begins to melt and particles of dust, dirt, gases are thrown into space. They form a kind of misty cloud around a comet called coma.
It’s not that a comet is a celestial body,which itself glows. The main light that it emits is reflected sunlight. Being away from the Sun, the light of the comet is not visible and, only approaching and receiving the sun's rays, it becomes visible. The comet itself emits a small amount of light, due to the atoms and molecules of the coma, which emit the quanta of sunlight they received. The “tail” of a comet is “crumbling dust,” which is illuminated by the sun.
Meteorites
Under the influence of gravity on the surface of the planetsolid cosmic bodies, which are called meteorites, can fall. They do not burn in the atmosphere, and when passing through it, they become very hot and begin to emit bright light. Such a luminous meteorite is called a meteor.
Under the pressure of air, a meteor can break upmany small pieces. Although it is very hot, its internal part usually stays cold, because in such a short time that it falls, it does not have time to heat up completely.
It can be concluded that celestial bodies thatglow themselves - this is the stars. Only they are capable of emitting light due to their structure and processes occurring inside the processes. Conventionally, it can be said that a meteorite is a celestial body that glows itself, but this becomes possible only when it enters the atmosphere.
