The rubber sheet analogy is criticised for this exact reason. Here’s a different visualisation that starts with what’s wrong with the rubber sheet: https://youtu.be/wrwgIjBUYVc
That's a great video. 7:50 is the important twist for me, and 10:25 really drives it home. I'll never forget that video now and it explains so much.
THere's still one "flaw" with this video: explaining that the grid "moves" is a little confusing. It doesn't move per-se, it .. evolves? ... over time. That's weird. I keep wanting to think the curves are static, but from t0->tn the grid pinches up. Yes, that's why they call it spacetime, but I have to stop and reset myself because how can the grid keep pinching up indefinitely but it doesn't it is just a concept. That is a stumbling block. 35 years after my last physics class...lol.
That’s the best visualization of gravitation I’ve ever seen. Well done. I recommend it to anyone who’s been misled by the ubiquitous rubber sheet picture.
That's clever. I'd suggest an improvement. When a sat has initial speed, show its small local reference frame, so we'd see that it always moves forward in its own reference frame, but the frame happens to be pulled to Earth.
THere's still one "flaw" with this video: explaining that the grid "moves" is a little confusing. It doesn't move per-se, it .. evolves? ... over time. That's weird. I keep wanting to think the curves are static, but from t0->tn the grid pinches up. Yes, that's why they call it spacetime, but I have to stop and reset myself because how can the grid keep pinching up indefinitely but it doesn't it is just a concept. That is a stumbling block. 35 years after my last physics class...lol.