So distances in space are dependent on what we use to measure them. As a consequence, we have at least two very different ways that we can choose to think about expanding space. The first, and more conventional, of these is to think of the amount of space in our universe as increasing. But alternatively, we could instead imagine that everything within space is shrinking, while space itself remains unchanged. Both ways of thinking about this are completely equivalent and indistinguishable from each other.
