The purpose of science is to get closer to truth. There is always things we don't know, or can't prove. The things we need to believe in, as scientific theories. The truths, until proven wrong.
Long time ago we believed we were living at the center of the universe. Later we have found out we are actually living at a rather unassuming edge of an average galaxy somewhere around the universe. We don't even live at the centre of our own solar system. Throughout the history we have iterated our place in the universe.
We don't live at the center of anything. But where is the center of our solar system? You probably "know" it's the Sun. Don't worry, I also thought so until recently, as did most of the science community too. Recent calculations have however proven that the center of our solar system isn't in fact where the Sun is. Not quite. It's not far of. After all, the Sun makes most of the mass of our system. But that diminutive rest is enough to pull the center of the mass a bit off. The actual (mass) center of our solar system is around 100 meters above the surface of the Sun.
While this new revelation doesn't change much, it does show that we shouldn't assume absolute knowledge. There can always be more precise information we can find with careful study.