This image compiles different times in the history of the universe: present day, 4 billion years ago and 11 billion years ago. The side-by-side comparison shows astonishing differences between the galaxies. The image of the universe today shows big, fully formed and elaborate galaxy shapes. Going back in time, the galaxies become smaller and less mature, as they're in the process of forming. The galaxies at earlier times are split between blue star-forming galaxies with a more intricate structure -- such as discs and bulges -- and colossal red galaxies that are no longer forming stars.