Stars are giant space objects in the form of balls of gas that emit their own light, unlike planets, satellites or asteroids, which glow only because they reflect the light of the stars. For a long time, scientists could not come to a consensus about why stars emit light, and what reactions in their depths cause such a large amount of energy to be emitted.
History of the study of stars
In ancient times, people thought that the stars are the souls of people, living beings or nails that hold the sky. They came up with many explanations for why stars shine at night, and for a long time the Sun was considered a completely different object from stars.
The problem of thermal reactions occurring in stars in general and on the Sun - the closest star to us - in particular, has long worried scientists in many areas of science. Physicists, chemists, astronomers have tried to figure out what leads to the release of thermal energy, accompanied by powerful radiation.
Chemical scientists believed that exothermic chemical reactions took place in the stars, resulting in the release of large amounts of heat. Physicists did not agree that reactions between substances take place in these space objects, since no reaction could give so much light over billions of years.
When Mendeleev opened his famous table, a new era began in the study of chemical reactions - radioactive elements were found and soon it was the reactions of radioactive decay that were named the main cause of the radiation of stars.
The controversy stopped for a while, since almost all scientists recognized this theory as the most suitable.
Modern theory of stellar radiation
In 1903, the already well-established idea of why stars shine and radiate heat was turned upside down by the Swedish scientist Svante Arrhenius, who developed the theory of electrolytic dissociation. According to his theory, the source of energy in stars is hydrogen atoms, which combine with each other and form heavier helium nuclei. These processes are caused by strong gas pressure, high density and temperature (about fifteen million degrees Celsius) and occur in the inner regions of the star. Other scientists began to study this hypothesis, who came to the conclusion that such a fusion reaction is enough to release the colossal amount of energy that stars produce. It is also likely that hydrogen fusion has allowed stars to shine for billions of years.
In some stars, the synthesis of helium has ended, but they continue to shine as long as there is enough energy.
The energy released in the interiors of stars is transferred to the outer regions of the gas, to the surface of the star, from where it begins to radiate in the form of light. Scientists believe that rays of light travel from the cores of stars to the surface for tens or even hundreds of thousands of years. After that, stellar radiation reaches the Earth, which also takes a lot of time. So, the radiation of the Sun reaches our planet in eight minutes, the light of the second closest star Proxima Tsentravra reaches us in more than four years, and the light of many stars that can be seen with the naked eye in the sky has traveled several thousand or even millions of years.