What are the stars that glow by themselves, and what are the stars that don't?

Stars that glow by themselves are called stars. A star is a spherical or quasi-spherical celestial body that can emit light by itself, and it is composed of non-solid, liquid and gaseous fourth plasma.

Because the stars are too far away from the earth, it is difficult to find their position changes in the sky without special tools and methods, so the ancients regarded them as fixed stars.

Stars are spherical luminous plasmas condensed by gravity, and the sun is the closest star to the earth. A star will carry out a nuclear fusion reaction of hydrogen fusion into helium at the core, transfer energy from the inside of the star, go through a long path, and then radiate from the surface to outer space. Once the hydrogen in the core is exhausted, the life of a star will be over.

Early universe

Finding the answers to these questions will certainly fill the gaps in the history of the universe. According to P MacDonald Douglas of the University of California, Santa Cruz, the beginning of the universe is a decisive period. "Re-ionization determines what happens next," he said.

For example, the size of a galaxy can be determined by considering how to ionize again. The matter that eventually combines into galaxies must be cooled to form galaxies-too hot, its components will jump violently, and gravity cannot combine them. Since re-ionization heats everything, it is difficult to combine anything unless the gravity is strong enough.

Therefore, the only possibility that the cloud cluster in front of the galaxy can gather into a galaxy under strong ionizing radiation is that it is very large, so its gravity can overcome the repulsive energy.