> For example, explaining with marbles falling down curved rubber sheets doesn't help, because you're using gravity (the marble being pulled down) to explain gr

> For example, explaining with marbles falling down curved rubber sheets doesn't help, because you're using gravity (the marble being pulled down) to explain gravity. Exactly, and it drives me nuts. There are many similar examples in SR and GR that maybe help a layperson intuitively, but creates confusion and frustration when you actually try to learn the theory. I can think of 2: The "escape velocity" explanation of black hole event horizon. Yes, the number comes out correct. No, it does not make sense and does not help me understand how black hole works. "Mass increases when object moves". No it doesn't. And no it doesn't explain why massive particles can't reach speed of light, because in the frame of the object, its speed is zero. I can't tell you how much time I've spent searching for the answers, and drowned by these answers that seemingly make sense.