Stars and star clusters, diffuse nebulae, planetary nebulae, dust clouds, neutral hydrogen, giant molecular clouds. The galaxy consists of a disk, a halo and a corona. The central, most compact region of the Galaxy is called the nucleus. There is a high concentration of stars in the core: there are thousands of stars in each cubic parsec. If we lived on a planet near a star located near the core of the Galaxy, then dozens of stars would be visible in the sky, comparable in brightness to the Moon. At the center of the Galaxy, a massive black hole is assumed.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.