4 ms·

> Well, actually, the speed of light is constant, it just takes time to ping-pong around a lattice/gas. Photons hit particles, get absorbed, and re-emitted, whi

by vecter 6y ago

> Well, actually, the speed of light is constant, it just takes time to ping-pong around a lattice/gas. Photons hit particles, get absorbed, and re-emitted, which causes an effective slowdown at a larger scale. A gas is just vacuum with particles floating around in it. When photons travel between those particles, they are traveling at c. The effective slowdown is determined by the lattice/gas, and we denote this slowdown with the refractive index... This is wrong. Two sources [0][1]. [0] https://www.youtube.com/watch?v=CUjt36SD3h8 https://www.youtube.com/watch?v=CUjt36SD3h8 [1] https://www.youtube.com/watch?v=CiHN0ZWE5bk https://www.youtube.com/watch?v=CiHN0ZWE5bk

anonytrary 6y ago
You're right, and it's a great example of how a classical analogy (lattice ping-pong) while "makes sense" is not what is physically happening. As I said, classical analogies cannot be taken literally, and this one is definitely a blunder on my part.
- andi999 6y ago
  So what is happening physically?
  - vecter 6y ago
    Did you watch the linked videos? They explain what is happening physically. It's not as simple as a macroscopic analogy to particles ping-ponging around. It relies on the wave properties of atoms and subatomic particles, mostly electrons.
    - anonytrary 6y ago
      But they don't, it's more just "here's the math, it's all about wave interference". It's quantum mechanics. You will fail if you try to explain it "physically" as I did above haha.
StavrosK 6y ago
I realized now that I hate videos. It would take me ten minutes to actually find the reason from each of your sources, while I could skim writing and get to the answer in seconds. Now I want to know why that's wrong but don't want to spend ten minutes getting refraction explained to me beforehand...
- TeMPOraL 6y ago
  Hence the superiority of text + images (or better yet, interactive diagrams and simulations) over video. In a sense, video is dimensionally reduced compared to an article. The information is serialized onto time axis. Whereas with articles, the information is serialized onto a spatial axis (usually vertical). A spatial axis supports rapid access, and viewing multiple point simultaneously, in a way that temporal axis doesn't.
  - StavrosK 6y ago
    I agree, but a video has much higher bandwidth (because of the images and audio). The problem is that YouTube optimizes for time watched, so we get long videos and no indexes. I wouldn't have minded a "crux of the video is at N:NN-M:MM".

by vecter 6y ago

anonytrary 6y ago

You're right, and it's a great example of how a classical analogy (lattice ping-pong) while "makes sense" is not what is physically happening. As I said, classical analogies cannot be taken literally, and this one is definitely a blunder on my part.

andi999 6y ago
So what is happening physically?
- vecter 6y ago
  Did you watch the linked videos? They explain what is happening physically. It's not as simple as a macroscopic analogy to particles ping-ponging around. It relies on the wave properties of atoms and subatomic particles, mostly electrons.
  - anonytrary 6y ago
    But they don't, it's more just "here's the math, it's all about wave interference". It's quantum mechanics. You will fail if you try to explain it "physically" as I did above haha.

StavrosK 6y ago

I realized now that I hate videos. It would take me ten minutes to actually find the reason from each of your sources, while I could skim writing and get to the answer in seconds. Now I want to know why that's wrong but don't want to spend ten minutes getting refraction explained to me beforehand...

TeMPOraL 6y ago
Hence the superiority of text + images (or better yet, interactive diagrams and simulations) over video. In a sense, video is dimensionally reduced compared to an article. The information is serialized onto time axis. Whereas with articles, the information is serialized onto a spatial axis (usually vertical). A spatial axis supports rapid access, and viewing multiple point simultaneously, in a way that temporal axis doesn't.
- StavrosK 6y ago
  I agree, but a video has much higher bandwidth (because of the images and audio). The problem is that YouTube optimizes for time watched, so we get long videos and no indexes. I wouldn't have minded a "crux of the video is at N:NN-M:MM".