As you can recall from the school course in natural history, stars are objects that have the ability to emit their own light. In contrast, other celestial bodies such as planets, satellites, asteroids and comets are visible in the sky due to reflected light, they do not have their own glow. The only exceptions are meteorites falling into the Earth’s atmosphere, falling due to its gravitational force. They burn partially or completely in the process of falling due to friction against air particles, and glow due to this.

But why do the stars shine? This is an interesting question that astronomers are ready to give an exhaustive answer.

The history of the study of stars and their glow

Over a long period of time, astronomers could not come to a consensus on the nature of starlight. This issue has given rise to much debate over the centuries. These disputes were not only scientific in nature - at the dawn of civilization, people built numerous myths, legends and religious speculations that explain the presence of stars in the sky and their glow. In the same way, legends and everyday explanations of other astronomical phenomena observed in the sky were created - comets, eclipses, the movement of the stars.

Interesting fact: some civilizations believed that the stars in the sky were the souls of the dead, while others believed that these were hats of nails that pinned the sky. The sun has always been considered separately, it has not been reckoned among the stars for millennia, it too differed in its appearance, observed from the surface of the Earth.

With the development of astronomy, the fallacy of such conclusions was clarified, and the stars began to be investigated anew - like the Sun. Subsequently, it was possible to clarify that the Sun is also a star. Modern scientists classify the nearest luminary to us as a red dwarf. However, the nature of the glow of the Sun and other stars gave rise to a lot of controversy until very recently.

Theories explaining the glow of stars

In the 19th century, many scholars thought that the process of burning on stars was exactly the same as in any earthly stove. But this theory did not justify itself at all. It is difficult to imagine how much fuel should be on the star so that it can give heat for millions of years. Therefore, this version is not worth considering. Chemists believed that exothermic reactions occur on the stars, which provide a powerful release of large amounts of heat.

But physicists will not agree with such an explanation, for the same reason as with the combustion process. The stockpiles of reactive substances must be huge in order to maintain the luminosity of the stars and their ability to give heat.

After Mendeleev’s discoveries, the situation changed again as the era of the study of radiation and radioactive elements began. At that time, the heat and light generated by stars and the Sun, unconditionally attributed to the reactions of radioactive decay, this version has become generally accepted for decades. Subsequently, it was repeatedly refined.

The current opinion of scientists about the causes of stellar glow

Modern scientists are fully convinced that nuclear fusion occurring in the nuclei of stars can provide the release of the amount of energy that every star emits every second. This process is capable of providing luminescence and heat generation in huge volumes for billions of years.

Therefore, the theory is considered generally accepted. Energy from the bowels passes into the gas shells of the star, from where its radiation comes from outside. In the circles of astronomers there is an opinion that tens, hundreds of thousands of years, are not an instant process to move energy from the bowels of a star to its surface. Therefore, a star can shine for a long time even after the synthesis in its bowels ceases due to a lack of initial chemical elements.

Light from any of the stars does not reach the Earth’s surface either instantly. Even from the Sun, the star closest to our planet, it takes about 8 minutes. The next star closest to our planet is Proxima Centauri. For light to reach Earth, it takes more than four years.

The light from distant stars goes even longer - thousands, tens and hundreds of thousands of years. The firmament visible today is a kind of reflection of the past, an already dead star may seem to us to exist as long as the light from it remains on the way. It is possible that a number of stars that can be seen every night in the sky have long been gone, but people continue to observe them due to the fact that the glow on the way has not yet run out.

Thus, stars shine due to nuclear fusion occurring in their bowels.This process provides the release of huge volumes of energy every second, while the fuel in the bowels of the star lasts for millions of years. When the elements necessary to maintain the nuclear process are exhausted, the star is able to glow for a rather long time. Then it transforms, and then completely collapses, forming a nebula from the sprayed gases, a black hole or other object. But while the star radiates energy - it lives.