2. What you can, or cannot, visualise is utterly irrelevant to the question of what is.
Yep. To paraphrase Dawkins somewhat, our brains have evolved cope with things of medium size moving at medium speeds in a three (four) dimensional world, with a certain amount of gravity etc. It doesn’t matter if something is counter-intuitive: intuition of the sort we’ve got has no place when talking about things on different scales from those we evolved to understand. What counts is what the evidence shows.
So, don’t try to visualise it. Instead, read up on (or just trust the people who have studied) the maths involved.
Cheers, DT
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