Photography - astronomy

Every atom in our body was once part of a star. The stars are among the most complex objects in astronomy. They have different characteristics and difficult stages of development. Stars form in clouds of gas that condensed under their own gravity. They become so hot and dense that their gas becomes opaque. The temperatures in the center are so extreme that atomic nuclei fuse with one another. Hydrogen is converted into helium, generating huge amounts of energy that is then emitted as radiation via the surface.

But a star is not just a star, these are divided into spectral classes. They not only differ in color, temperature and size, their résumés are also very different. As soon as a star has found equilibrium after birth, it goes on the main sequence. He spends most of his life here. If its hydrogen runs out, it leaves the main sequence and its mass determines its further fate. The sun will get brighter and cooler and grow into a red giant. Then it will shed its shell and a planetary nebula will form. The final stage will then be a white dwarf. Massive stars grow into supergiants and destroy each other with a supernova. This creates neutron stars or even black holes.

The sun is 4.6 billion years old. Our solar system is only a tiny part of the Milky Way, which is 13 billion years old. The number of stars is estimated at 200 billion. 85 percent of the luminosity in the Milky Way is generated by B stars, which make up only 0.15 percent of the main sequence stars.