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I've watched this video recently : https://www.youtube.com/watch?v=pTn6Ewhb27k (Why The Speed Of Light* Can't Be Measured on the Veritasium channel).

I think I understand the concept. Speed of light is C in all directions by conventions, but the math hold true if it's C/2 in one direction and infinitely fast in the other (and all in beetweens). All the math cancels out this perfectly giving the same answer for each questions.

But in this case, the observable universe should be warped in a some what oblong shape (infinitely long if you go to the extreme C/2 infinitely case)? And thus if we can see more of the sky in one dirrection and this part should include more glowy stuff making it brighter.

I guess you could answer this easly by: "the expending speed of the universe would also vary in fonction of the speed of light canceling the effect perfectly" but I'm not sure of how that would looks like nor I have bother to learn all the calculations to do to check that.

(my main problem is I could accept different part of space time expending at different rate, but this isn't the same thing, this would be the same part of space expending at different rates depending of the dirrection)

Basicaly it's just a variant of the bright night paradox, that was old and was easly answered when we discovered that the speed of light isn't infinite, but now someone telling that speed of light might be under certain circumstance infinite, why doesn't the bright night paradox applies here?

Dale
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Jorropo
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  • Does this answer your question? Can One-Way Speed of Light be Instantaneous? – Dale Feb 14 '21 at 02:10
  • @Dale that really good thx but no, this is very well written and goes in great details but this is just saying with more words "there are math backing this and this is the same".

    I was hopping for a more intuitive answer of why the observable universe isn't oblong in a non isotropic speed of light universe (if it do is). Like could someone show me where this does cancels out (hopping it's not too difficult) ?

     – Jorropo Feb 14 '21 at 02:18

1 Answers1

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If the speed of light is anisotropic then time dilation is also anisotropic. This means that the universe is considerably older in one direction and younger the same distance away in the other direction.

So the light that arrives to us from far away in the “fast” direction shows us a portion of the universe that is now very young as it is now. And the light that arrives to us from far away in the “slow” direction shows us a portion of the universe that is now very old back when it was young. So we see the young universe in the light from far away regardless of the direction.

Dale
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