The sheer scale of the universe makes it difficult to represent in an image. But using a logarithmic scale makes for a useful representation.
Logs of Nature
We generally think of numbers as a linear progression from 1 to 2 to 3, etc. We also tend to measure things around us on a linear scale. A ten hour road trip, for example, is very different from a one hour trip. In the sciences, however, it is often more useful to look at things on a logarithmic scale.