Everything we can observe . Considered the distances we are talking about. The universe is so big it staggers the mind and we can actually observe only the largest of events and even then we can only see maybe a small percentage of the original, such as an undefined little blob, which in reality might be as big as our entire galaxy. There is a difference between water waves and the Universal Pilot Wave. https://en.wikipedia.org/wiki/De_Broglie–Bohm_theory Consider that we see stars today which no longer exist at all. They went nova millions of years ago and their light hasn't reached us yet. Moreover when we go back that far in time we don't see things anymore. We receive EM (radio) waves from only the largest events and objects. Now that we are in space and can look further back we can see more, but still older events are stil only observable via EM waves.