How are Galaxies Formed? Home Where are we? What is a galaxy? What is at the center of our galaxy? What does gravity do in a galaxy? Dark Matter Bibliography	After the big bang, particles began to form. Once particles began to form, large clusters of particles started grouping up. These groups then compressed together because of gravity, interacting with other groups of particles, and pulling them towards one another. Stars began to take shape. Large groups of stars felt an attraction to one another, pulling each toward others. Through this process, galaxies were created. Image credit: jootix.com
	On a slightly smaller time scale than all of time so far, the creation of galaxies through the uptake of matter occurs mostly in one to four billion years. Although they continue to grow through collisions with other dwarf galaxies, the collisions become much less frequent as time goes on. The Milky Way itself is set to collide with a neighboring galaxy, Andromeda, in five to six billion years. Video credit: youtube.com