On: Ask HN: Concepts that clicked only years after you first encountered them?

[7373737373]

I'm not sure how this works out in media which slow down light

https://en.wikipedia.org/wiki/Cherenkov_radiation

There, e.g. gravitational waves will be at c (in a vacuum), but wouldn't photons experience time there?

Edit: I suppose the photons are still actually moving at c

[djmips → 7373737373]

I had thought because light was absorbed and re-emitted but that and scattering ideas are incorrect. See this video for an explanation of why light travels slower through a medium with an index of refraction greater than one. https://youtu.be/CUjt36SD3h8