How gravity works
Once you understand that there is no time flowing inside an optical clock, then you understand that an optical clock goes slower when it’s lower because light goes slower when it’s lower. Because the speed of light varies in the room you’re in. After that you understand that light waves curve downwards in a gravitational field for the same reason that sonar waves curve downwards in an ocean. Search the ES310 sonar propagation webpage and you find where the US Navy said it: “Recall how differences…