The distance between galaxies is measured in light years. No human being or any power which we know of has the ability to control objects at such distances. So there is a super power far more intelligent and capable of maintaining the equilibrium over millions of years even before the birth of mankind. What is that power?
Such questions lead philosophers to make educated and intelligent guesses based on probabilities, commonsense and extra human consciousness. Their inferences were passed down over centuries from generation to another by word of mouth. Such knowledge is fraught with error and distortions during transmission.
The universe seems to be controlled in its existence by various laws of Physics, Chemistry, Biology as we discovered them due to studies of Newton, Einstein and many others. So our knowledge is very recent while our ignorance is huge.