Einstein described a Newtonian gravity well as a curvature of the field. If you assume that there is no aether particle field, then you are left to say that the curvature of the field is the curvature of empty space.

Spacetime is based on the concept that light travels at a limited speed, and therefore the information you receive from the universe must take into account where and when the signal was sent. In other words, the limited speed of light will produce illusions that must be accounted for when "decoding" your observations. Special relativity and then GR take this a step further and say that the "illusions" are physically determinant - for example: he claims that travelling fast makes clocks go slower, but whilst you are travelling really fast you do not see your clock as going slower. Then when you get home less time will have past for you than for you twin brother who stayed at home. He is claiming that not only did the clock go slower, but that time went slower, hence you aged less than your non-travelling brother. This concept can also be expressed by sentence: "sit down and smoke another one".

Yes, but I believe you will have aged less not because time ran slower, but because atoms decay slower in high gravity fields or at high velocities. If the trip is 10 years both brothers will say ten years passed, yet one is younger. not because less time passed for him, but because his atoms decayed slower. Well one will argue time went slower, but what is time but the decay of atoms. So the only possible solution is a standard clock free of all gravitational and velocity affects (an impossibility.) I still say both clocks agree, if you convert either one to the other frame, which you MUST do if you want to compare them, else comparison is useless, then both clocks agree that either 10 years has passed or less, depending on which frame is converted to which frame. If your clock says a second is so long and it says the other is shorter, then both cannot be seconds from your frame. But if convert his frame to your frame, then both become seconds of the same duration again, and vice versa.

It's all a mind game to prevent you from looking at the base presumptions and equations and discovering their flaws