The galaxies are a very large disciplined system bounded by gravitational force, which are composed of stars, interstellar gas and dust, plasma and abundant invisible objects. In a typical galaxy, there are 10 million to one trillion people who are all rolling around a common gravitational center. In addition to the isolated stars, there are galactic systems in the galaxy, they are stellar and various types of nebula.
Most galaxies range from hundreds of light years to thousands of light years and distance between galaxies at a distance of million light-years.
About 90 percent of the galaxy is responsible for the mass, but the invisible object is very uncertain about their existence and structure. Evidence of the existence of the largest black hole inside the galaxy has been found. Interstitial space is full of light plasma. There are more than 100 billion galaxies in our observational range.
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