What Are the Forces That Shape the Universe?
In the previous chapter we discussed the energy content of the universe, the different types of matter that we see, or actually don’t see. So far we have only briefly mentioned what forces come into play and what the nature of these forces is. We also haven’t discussed how the matter constituents interact with each other and what forces govern these interactions, from the smallest to the largest distance scales. We shall do this in the following, beginning with a discussion of what forces there are, and then move on to what a force actually is and discussing finally how these forces shape the evolution of the universe.