5 ms·
That is interesting. But then what is the explanation? Medium is not really anything concrete, we call that a collection of atoms isn't it? By default there is
by loopies 7d ago
That is interesting. But then what is the explanation? Medium is not really anything concrete, we call that a collection of atoms isn't it?
By default there is only one medium, the vacuum of space, in which there can be various densities of "stuff", particles/atoms/molecules.
So then, it becomes some sort of quantum thing, a probability of photons bumping/being captured/emitted or?
- gattr 7d agoSimplifying from memory, light propagation in medium can be treated on two levels (some phenomena require the 2nd, quantum, level): - classical (Maxwell): electrons in the medium oscillate out of phase in response to the incident wave; this results in a new wave, propagating somewhat slower - quantum (QED): incident photon couples to matter excitation (an exciton), producing a pseudo-particle called a polariton; it has a non-zero effective mass, resulting in propagation slower than c As mentioned above, it absolutely isn't "absorbing and re-emitting". If that was the case, transparent materials would not exist (only milky/clouded ones), as re-emission is in random direction. However, photon propagation in the Sun is just that, a (very long, counting from the core to photosphere) random walk.
- loopies 7d agoThank you, that is very interesting! I remember seeing something about absorption/emission and seemed to make some logical sense. But indeed if emission is in a random direction then transparent materials wouldn't make sense.