The Cosmic Microwave Background and the Growth of Galaxies

The large scale structure of the early Universe is believed to have resulted from the small fluctuations in the cosmic microwave background. In this map, red areas represent places in the Universe where the temperatures were slightly higher and had slightly less matter, and blue areas represent places in the Universe where the temperatures were slightly lower and had slightly more matter. Since the distribution of matter was not perfectly uniform, over time gravitational forces began to shape where in the Universe there would be higher and lower concentrations of galaxies.