IntroductionThe Universe is a collection of millions of galaxies and extends beyond human imagination. After the big bang it was discovered that the universe was composed of radiation and subatomic particles. Post-big bang information is questionable about how galaxies formed, i.e. whether small particles merged to form clusters and eventually galaxies or whether the universe systematized as immense clumps of matter that subsequently fragmented into galaxies (book Nasa World, 2013). A galaxy is a huge area of ​​empty space filled with dust, gas (mainly 75% hydrogen and 25% helium), atoms, about 100-200 billion stars, interstellar clouds and planets, attracted to the center by the gravitational force of attraction. Based on recent research, it is estimated that 170 billion galaxies exist, of which only tens of thousands have been discovered (Deutsch, 2011). Structure of galaxies Astronomers believe that most galaxies consist of a supermassive black hole at the center, which attracts all the constituents of the galaxies. such as dust, gas (mainly hydrogen and helium), atoms, stars, interstellar clouds and planets moved to the center by the force of gravity, but they are not sure that all galaxies contain a black hole at the center. Galaxies continue to move in relative motion with respect to each other and intermittently may move so close together that the gravitational attraction force between the galaxies may become strong enough to cause a change in the shape of the galaxies, while in exceptional cases the galaxies can collide. If two galaxies collide, they may pass through without any effect or merge, forming filaments of stars, which extend over 100,000 light years into space (World Book Online Reference Centre, 2005). Thus, nearby galaxies and often other colliding galaxies induce the sha...... middle of paper ...... on the search. On August 2, 2007 approximately more than 10 million images of galaxies were classified by the Galaxy Zoo program (Galaxy Zoo).ConclusionIn general, the universe began as a composition of radiation and subatomic particles, which proceeded to form galaxies. Galaxies are made up of hydrogen, helium, 100-200 billion stars, planets and most have a black hole at the center, which attracts everything present in the galaxies by force of gravity. Galaxies can be classified as spiral (the Milky Way, the galaxy in which mankind was discovered to exist), elliptical, lenticular and irregular, where the structure is determined by nearby galaxies and most galaxies move further away l 'from each other. Galaxy classification is conducted by online programs such as Galaxy Zoo, using images from telescopes, and is making significant progress.