Stars are heavenly bodies that shine themselves

Astronomy is a science that deals with the study of celestial objects. He considers stars, comets, planets, galaxies, also does not disregard existing phenomena that occur beyond the atmosphere of the Earth, for example, cosmic radiation.

Studying astronomy, you can get an answer to the question "Celestial bodies that shine themselves. What it is?".

The bodies of the solar system

To find out if there are celestial bodies that shine themselves, it is first necessary to understand the celestial bodies of which the solar system is composed.

The solar system is a planetary system in the center of which there is a star - the Sun, and around it are 8 planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. To call the heavenly body a planet, it must meet such requirements:

• Make rotational movements around the star.
• Have a shape in the form of a sphere, due to sufficient gravity.
• Do not have around your orbit other large bodies.
• Do not be a star.

The planets do not emit light, they can only reflect the rays of the sun that fall on them. Therefore, it can not be said that the planets are heavenly bodies that shine themselves. Such heavenly bodies are the stars.

The sun is the light source on earth

The heavenly bodies that shine themselves are the stars. The nearest star to the Earth is the Sun. Thanks to its light and warmth, all living things can exist and evolve. The sun is a center around which the planets, their satellites, asteroids, comets, meteorites and cosmic dust revolve.

The sun seems to be a solid spherical object, because when you look at it, its outlines look quite distinct. 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 does not have clear contours, one must look at it during an eclipse. Then you can see that it is surrounded by a moving atmosphere, which is several times its diameter. With ordinary shining, this aureole is not visible because of the bright light. Thus, the Sun does not have exact boundaries and is in a gaseous state.

Stars

The number of existing stars is unknown, they are located at a huge distance from the Earth and are visible as small dots. Stars are heavenly bodies that shine themselves. What does this mean?

Stars are hotballs consisting of gas in which thermonuclear reactions occur. Their surfaces have different temperatures and densities. The sizes of a star also differ among themselves, thus they are more and more massive than planets. There are stars whose dimensions exceed the size of the Sun, and there is also the other way around.

The star consists of gas, more of it hydrogen. On the surface of it, from a high temperature, a hydrogen molecule breaks up into two atoms. An atom consists of a proton and an electron. However, atoms under the influence of high temperatures "release" their electrons, resulting in a gas, which is called - plasma. An atom that is left without an electron is called the nucleus.

How stars radiate light

The star, due to gravitational force, tries to squeeze itself, as a result of which the temperature in the central part of it rises. Nuclear reactions begin to occur , resulting in the formation of 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 stand out as an excess of energy - they also carry light. This light exerts a strong pressure, which comes from the center of the star, resulting in an equilibrium between the pressure exerted from the center and the gravitational force.

Thus, the celestial bodies that shine themselves, namely the stars are lit by the release of energy in nuclear reactions. This energy is aimed at restraining gravitational forces and on the emission of 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 which gases and dust are present. Its core does not emit light, but as the Sun approaches, the core begins to melt and particles of dust, dirt, and gases are thrown out into outer space. They form a kind of fog cloud around the comet, which is called a coma.

It can not be said that a comet is a heavenly body, which itself glows. The main light it radiates is reflected sunlight. Being far 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 that secrete the photons of sunlight they have received. The "tail" of a comet is "scattered dust", which is illuminated by the Sun.

Meteorites

Under the influence of gravitation, solid cosmic bodies, called meteorites , can fall to the surface of the planet. They do not burn in the atmosphere, but when they pass through it they heat up strongly and start to radiate a bright light. Such a luminous meteorite is called a meteor.

Under the pressure of air, a meteor can be broken into many small pieces. Although it is very hot, its internal part usually remains cold, because in such a short time that it falls, it does not have time to warm up completely.

It can be concluded that the heavenly bodies that shine themselves are stars. Only they are able to radiate light at the expense of their structure and processes occurring inside. Conventionally, it can be said that a meteorite is a heavenly body that glows itself, but this becomes possible only when it enters the atmosphere.