Galaxy formation and evolution

Galaxies are huge collections of stars, dust, and gas that live in space and all across the universe. They form when gas and dark matter clump together like a big cloud and eventually become so big, they start to spin. As they continue to spin and get bigger, gravitational forces cause bigger things to smash into the cloud and pull it apart. Over time, the clump becomes big enough to start forming stars, and these stars get pulled together by gravity to form galaxies. As galaxies grow, they also change and evolve. Over time, some galaxies get bigger by merging with other galaxies, and some galaxies run into each other and tear themselves apart. Ultimately, galaxies keep getting bigger, brighter, and more complex as they continue to grow and change throughout the universe.