A new way to visualize General Relativity

This is definitely the smartest video I&#x27;ve seen in years, perhaps ever.<p>Questions I have: If the apple were traveling back in time would it essentially be falling away from the earth instead of falling into it? Would traveling forwards in time like George did in The Time Machine 1960 film (or the unnamed protagonist of the book), would essentially get crushed by ramming himself into the earth? I like these notions because it helps relieve me of grandfather paradoxes of time travel and make me dream of travel to the stars without having to forever say goodbye. Also like the fact that it doesn&#x27;t require an extra incomprehensible dimension like in the case of warp bubbles.

I don&#x27;t know if I&#x27;ve seen this video before, but the way it describes and animates the concepts is the best one yet.<p>I have two thoughts that I haven&#x27;t really seen discussed:<p>1. c isn&#x27;t a limiting speed, it&#x27;s the <i>only</i> speed through spacetime. Is there anything that isn&#x27;t traveling at c through spacetime?<p>2. If everything is traveling at c through spacetime, then the all the spacetime dimensions are not in fact independent, so we live in 3 dimensions of spacetime. Given that why do we doubt or debate a holographic view of the universe? It&#x27;s saying we live in 2D space and 1 time which is an interpretation of living in 3D spacetime.