Astronomy is a science that studies celestial objects. It examines stars, comets, planets, galaxies, and also does not disregard existing phenomena occurring outside the Earth’s atmosphere, for example, cosmic radiation.
By studying astronomy, you can get the answer to the question “Heavenly bodies that shine themselves. What it is?".
Bodies of the solar system
To find out if there are celestial bodies that shine on their own, you first need to understand what kind of celestial bodies the solar system consists of.
The solar system is a planetary system in the center of which there 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 movements around the star.
- Have the shape of a sphere due to sufficient gravity.
- Do not have other large bodies around its orbit.
- Do not be a star.
Planets do not emit light, they can only reflect the rays of the Sun hitting them. Therefore, it cannot be said that planets are celestial bodies that shine on their own. Such celestial bodies include stars.
The sun is the source of light on Earth
The celestial bodies that shine on their own are stars. The closest star to the 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 revolve.
The sun seems to be a solid spherical object, because when you look at it, its contours 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 does not have clear contours, you need 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. Under normal radiance, this halo is not visible due to 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 celestial bodies that shine on their own. What does this mean?
Stars are hot balls made up of gas in which thermonuclear reactions occur. Their surfaces have different temperatures and densities. The sizes of the stars also differ from each other, while they are larger and more massive than the planets. There are stars whose sizes exceed the dimensions of the Sun, but there are vice versa.
A star consists of gas, more of it hydrogen. On its surface, from high temperature, a hydrogen molecule decomposes 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 called plasma. An atom left without an electron is called a nucleus.
How stars radiate light
The star, due to gravitational force, tries to compress itself, as a result of which the temperature rises strongly in its central part. Nuclear reactions begin to occur , as a result helium is formed with a new nucleus, which consists of two protons and two neutrons. As a result of the formation of a new core, a large amount of energy is released. Particle photons are released as an excess of energy - they also carry light. This light exerts a strong pressure that emanates from the center of the star, resulting in a balance between the pressure emanating from the center and gravitational force.
Thus, celestial bodies that shine themselves, namely stars, shine due to the release of energy during nuclear reactions. This energy is aimed at restraining gravitational forces and emitting light. The more massive the star, the more energy is released and the brighter the star shines.
Comets
The comet consists of an ice clot in which gases and dust are present. Its core does not emit light, however, when approaching the Sun, the core begins to melt and particles of dust, dirt, gases are released into outer space. They form a kind of foggy cloud around the comet, which is called - coma.
This is not to say that a comet is a celestial body that itself shines. The main light that it emits 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, which emit quanta of sunlight received by them. The “tail” of a comet is a “scattering dust” that is illuminated by the Sun.
Meteorites
Under the influence of gravity, solid cosmic bodies called meteorites can fall on the surface of the planet. They do not burn in the atmosphere, but 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 up into many small pieces. Although it heats up very much, its inner part usually remains 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 that shine themselves are stars. Only they are able to radiate light due to their structure and processes occurring inside. Conditionally, it can be said that a meteorite is a celestial body that itself shines, but this becomes possible only when it enters the atmosphere.