If it is, then there must have been a time when everything was much closer together. Astronomers now believe that 12 to 15 billion years ago all the stars and galaxies in the universe were squashed together in a tiny space. We will be closer to an answer when we know the value of the Hubble Constant. Many astronomers are working on the problem. To discover the value of the Hubble Constant we have to know how fast galaxies are moving and how far away from us they are.
Astronomers know pretty accurately how fast galaxies are moving by their color.
When something moves toward you very, very fast, it looks a little bit bluer, and when it moves away it looks redder. So astronomers can measure speeds by how red a galaxy looks. Objects look redder as they move away, and bluer as they move toward us. Finding out how far away the galaxies are is harder. We can't send rockets to measure the distance, it would take millions of years for a rocket to go even part of the way to another galaxy.