January 22, 2022

A star (Ijek. Star) is a celestial body that radiates its own light. It is spheroidal in shape, and in the state of plasma (highly ionized gas at high temperature) it consists mostly of hydrogen and helium, and only a small part of other elements. The star creates energy in its core by thermonuclear reactions. This energy is transmitted to the surrounding space by convection and electromagnetic radiation and particles. Most of the atoms of chemical elements heavier than helium that currently exist in the universe, as well as all elements heavier than lithium, were formed in the centers of stars through the process of nucleosynthesis. The closest star to Earth is the Sun, the source of light, heat and life for our planet. Other stars (with the exception of some supernovae) are visible only during the night, as bright spots in the sky that flicker due to the effect of the Earth's atmosphere. In everyday speech, the term star is sometimes considered to be visible planets, and even comets and meteors. The closest star to Earth, except the Sun, is Proxima Centauri, which is about 40 Pm (five meters) away, or 4.3 SG (light years), or 1.3 pc (parsec). This means that it takes 4.3 years for light to reach the Earth from this star. However, in addition to this distance and several times greater distances, there are several other stars that we consider the closest (see the list of nearest stars). There are an estimated 200 billion stars in our galaxy. The relationship between the brightness and the size of the star is shown by the Herzsprung-Russell diagram. It is believed that there are at least 70 sextile stars in a known part of our universe (70 000 000 000 000 000 000 000 or 7 × 1022). A large number of stars are about a billion or 10 billion years old. Some stars can even reach 13.7 billion years, which is the approximate age of the universe. According to their size, we distinguish tiny neutron stars (which are in fact dead stars no bigger than a small town), supergiants such as the North Star and Betelgeuse, which is about 1,000 times larger than the Sun's, but even before that they are much denser than the Sun. One of the most massive stars is Eta Pramca, whose mass is 100-150 times greater than that of the Sun. Stellar astronomy studies stars and phenomena that show different shapes / developmental states of stars. It is estimated that most stars are associated with gravity

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