Milky Way
The galaxy is a group of giant objects that are formed by gravitational tethering of stars, density, interstellar matter, and dark matter. The term "galaxy", which means galaxy, comes from the Greek word "Galaxias", which means the Milky Way. The galaxies are made up of less than 10 million stars, and the big ones have about 100 stars, which all revolve around the center of mass of the galaxy. The sun also revolves around the galaxy like other stars with the Earth and other solar systems. Within the galaxy are a number of star systems, clusters, and interstellar clouds, and the space between them is filled with interstellar matter consisting of gas, dust, and cosmic rays. We do not yet understand the exact nature of the matter, and materials called dark matter are generally thought to account for about 90% of the mass of galaxies. On the other hand, according to many observational results, it is believed that an ultrahigh mass black hole exists at the center of almost all galaxies.