General Relativity

General Relativity is much simpler to grasp than special relativity because all that it does is expand on it. Basically all that general relativity is a description of how gravity warps space-time, that quantity we discovered in special relativity. What general relativity says is this; being in a gravitational field (note that gravity permeates the whole universe) will have the same effect on the flow of time as moving, that is, being in a gravitational field slows time for everything in that field. It also said some interesting things about accelerated motion, that being accelerated in a direction and standing on an immovable object in a gravitational field (like standing on the surface of the earth) are the same thing. This has gone on to say many things about the nature of black holes, which we will cover at a later time. For example, let us use a common analogy, two twins are separated at birth and one is left on earth while the other is put in an environment with a much stronger gravitational field, after twenty earth years the twins are reunited and to their surprise the twin that was left on earth was significantly older than the twin that was put near a black hole. This is because since the gravitational field is so much stronger at a black hole than on Earth, so time moves slower there.