Science4All (english)'s video: General relativity explained Relativity 15

Last time, we saw that Einstein explains the falling of the apple by the upwards acceleration of the ground. This is Einstein's happiest thought. But wouldn't this imply that the surface of the Earth is expanding outwards? Well, no. Why? Because of spacetime curvature! At last, this video explains how Einstein's gravity really works. Warning! This video is a bit more technical than usual, and previous videos are prerequisites to fully grasp this one. They include: Is special relativity relative? Time dilation and space contraction | Science4All 6 https://www.youtube.com/watch?v=KLsFYofL5Dc What's wrong with that map? Spherical Geometry | Science4All 9 https://www.youtube.com/watch?v=SZsz3EchTA0 What's a straight line? Curved-space geometry | Science4All 10 https://www.youtube.com/watch?v=n8DB3mGXEUg What's the geometry of my underpants? Hyperbolic Geometry | Science4All 11 https://www.youtube.com/watch?v=PBDcMrq-BSQ Are astronauts weightless? Einstein's happiest thought | Science4All 14 https://www.youtube.com/watch?v=9s2tObpO_rU More to understand general relativity... Spacetime of General Relativity | Science4All Article http://www.science4all.org/le-nguyen-hoang/spacetime-of-general-relativity/ Is gravity acceleration or curvature? Follow-up clarifications | Science4All 16 https://www.youtube.com/watch?v=WbhUsPuioN8 Is Gravity An Illusion? | Space Time | PBS Digital Studios https://www.youtube.com/watch?v=NblR01hHK6U General Relativity & Curved Spacetime Explained! | Space Time | PBS Digital Studios https://www.youtube.com/watch?v=AwhKZ3fd9JA What proved general relativity? Einstein's heart palpitations | Science4All 17 https://www.youtube.com/watch?v=IxS_4Z6_wBA What's the destiny of the universe? Einstein's biggest blunder | Science4All 18 https://www.youtube.com/watch?v=ZAiVf4zA6KI What's gravitational time dilation? Twin & Grandfather paradox | Science4All 20 https://www.youtube.com/watch?v=wV9yqfNQTgo