this post was submitted on 19 Nov 2023
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submitted 11 months ago* (last edited 11 months ago) by fossilesque@mander.xyz to c/science_memes@mander.xyz
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[–] Neato@kbin.social 6 points 11 months ago (2 children)

That's light as an aggregate wave. Photons, actual light, always travel at c. What's happening in a medium is the rapid absorption and readmission of photons. The probability of admission is based on structure of material causing things like lens or mirrors to work.

You can think of it as the photons having to jump between platforms before the can continue running at c.

[–] Entropius@lemmy.world 3 points 11 months ago (1 children)

What's happening in a medium is the rapid absorption and readmission of photons. […]

You can think of it as the photons having to jump between platforms before the can continue running at c.

That’s an intuitive model, but unfortunately it doesn’t have the advantage of actually being correct. Photons are not being absorbed and reemitted. See here for why: https://lemmy.world/comment/5444224

[–] Neato@kbin.social 0 points 11 months ago (1 children)

That is wrong. Stochastic yes. Photons emission is probabilistic. Destructive interference causes emission to overwhelming follow classical wave theory. Here's a better explanation with a neat graphic.

https://physics.stackexchange.com/questions/466/what-is-the-mechanism-behind-the-slowdown-of-light-photons-in-a-transparent-medi

[–] Entropius@lemmy.world 2 points 11 months ago

It sounds like you’re conflating different concepts. A stochastic process like absorption/reemission would blur the light, so that’s not it. And the linked explanation is basically correct (in classical physics at least), but it doesn’t corroborate what you originally claimed as that’s not necessarily requiring absorbing anything. Photons can jiggle the charged particles in glass and get them to make new phase shifted light despite not being absorbed.

https://youtu.be/YW8KuMtVpug

https://youtu.be/CiHN0ZWE5bk