In flight school, I used to wonder a lot about a four dimensional space time. I was fourteen. I could fly planes before I was allowed to drive a car. It’s not just a (maybe) thing. Space time is very real. Imagine the whole of space is contained within a vast rectangular three-dimensional box. To define any kind of event taking place within the box, we assign to it X, Y, and Z coordinates along with a value for time. What if we could add a time axis to the three of space. It would require right angles. We experience the passage of time to be a steady crawl. The gravitational pull that a human body feels is a measure of the curvature of space around it. It is gravity that slows the flow of time. It is gravity that gives time a shape. It is counter intuitively some very weird shit.