In the case of a clear night sky, a large number of stars can be seen, which seemingly group into shapes called constellations. Thanks to the starlight, we can now enjoy the view of the night sky. In earlier times, the night sky was used, for example, for navigation. But what is it that the stars shine?
Stars are spherical cosmic objects that have their own source of visible energy. This radiation is caused by a thermonuclear fusion in the star's core, most often by the conversion of hydrogen to helium, or by the fusion of heavier elements. The released energy in the form of gamma radiation passes through the interior of the star and is radiated into outer space.
The stars differ in the color they shine. This color is given by the most intense frequency of radiation in the visible spectrum that the star emits. This most intense frequency is then given by the temperature on the star's surface. Colder stars appear red and warmer stars appear white.
In addition to visible light, however, the star emits at all wavelengths from long radio waves to very short gamma rays. In addition to electromagnetic radiation, the star emits free protons and electrically charged alpha and beta particles, which we call the stellar wind.