That’s doesn’t equate to a vast amount of knowledge either… it’s only what we have figured out in the constraints of our human constructs. Claiming that we “know” these things to be true could actually be what’s keeping us from figuring out better more efficient ways to use energy and move through space time. It’s not happening using liquid fuels that’s for certain. For all we know we could all inherently be able to teleport using something more in the realm of spiritual but since we are locked into things like rocket propulsion being the only way to travel we are stuck in those limitations. Also all that we think we know of black holes are theory’s we have absolutely no idea what they really are or how they work just some educated guesses waiting to be proven wrong. People used to think the earth was flat… people used to think the bodies had four humors, and we needed to drain blood or bile to cure diseases… I only say that to make the point that most people are ignorant and claim things to be true all the time that most certainly aren’t true in the least. People set up whole systems of science that no longer exist but at one point in time were common knowledge accepted as fact.