The birth of stars can be the “primary” nebula produced by the Big Bang, or the nebula after a supernova explosion. When the gravity of the local matter is greater than the thermal expansion pressure, the collapse of the nebula will occur quickly. This process is not long, such as sun-like stars. It only takes about hundreds of thousands of years to produce a protostar! When the temperature and pressure of the inner core are sufficient for the fusion of hydrogen nuclei, the star will enter the main sequence star stage, because at this time the internal radiation pressure will compete with the external gravitational collapse, the star will no longer collapse, and the generation of stellar wind will also drive Without nebula matter, stars no longer grow. Stars in the main-sequence stage are very stable, but when the hydrogen fuel in the core is burned out, the core shell begins to burn. At this time, the hydrogen in the shell burns violently due to a sharp rise in temperature and pressure, and a red giant star will form!
If the star is large enough, such as 8 to 10 times the mass of the sun, it will be born and become a supernova. Of course, it will not disappear after the explosion. A neutron star and black hole will be left in the center, and a large supernova wreck will be left outside. If the mass of the star is relatively small, a white dwarf will be born, and its lifespan is super long. Even if the universe was born with a white dwarf, it will continue to exist until now, while the life of a red dwarf formed by a smaller star can exceed hundreds of billions of years or even trillion years. Therefore, under normal circumstances, when stars disappear, their remains can be found. In addition to the Crab Nebula, there are also very beautiful planetary nebulae. Even we can occasionally see the process of supernova explosions. For example, Betelgeuse in Orion is a potential star. Supernova!
Scientists began studying these bizarrely vanishing stars in 2017 using data from ESA’s Gaia satellite, in addition to Zwicky transient light changes from the 48-inch Samuel Oschin Telescope at the Palomo Observatory in California. Event monitoring! After repeated comparisons, a total of more than 800 stars were missing, and after calling the star data port of the Gaia satellite, it was found that there was nothing left in the area where these stars were located, not even any remains after the supernova explosion. It is almost impossible to know that a star is completely extinguished, and it is impossible for humans to discover its existence. Just like the incandescent lamp in our home, it detects with infrared rays after it is turned off, and can still find the afterglow in the infrared band.
And the only way to extinguish all these stars may be the Dyson sphere in advanced civilizations. This is an advanced civilization imagined by astronomer Dyson to use the energy of the stars to build a sphere surrounding the stars in order to use 100% of the light and heat of the stars. Since the diameter of the stars is often millions of kilometers, the scale of this building is astronomical. level! Of course, this is just a conjecture. There are still many mysterious things in the vast universe that we humans cannot explain. Maybe it’s just because human science and technology haven’t reached a certain level.