1. Electromagnetism tells us that electromagnetic waves changes its velocity of propagation according to the medium it is propagating into.
2. Special relativity tells us that massless particles must propagate at c
How the hell aren't these 2 statements inconsistent? I mean they can only be consistent if there is a process of interaction between the photons and the matter that ends up delaying the photons (like being absorbed and emitted again), is that what happens?
Tldr: Explain to me how does photons interact with matter in a way that makes it seem to be propagating at speeds lower than c
>massless particles must propagate at c Lrn2vacuum fgt pls
Jordan Cooper
c is the speed of a massless particle specifically in vacuum (different then the speed of a massless particle in a non-vacuous medium) you dense twat.
Jacob Miller
So photons really propagates at speeds lower than c? Why does that happen? I mean microscopically why is the photon deaccelerated?
Elijah Jones
It isn't. It travels at c, always. In water or glass, the photon is absorped and emitted by the electrons in the media and increasing the time it takes to transverse the material.
Jaxon Reyes
it's not. and are retarded.
Jonathan Sanchez
Speed != velocity
Levi Nelson
Thanks that's what I was thinking about, do you have any source that says more about that?
Easton Flores
Bumping for sources
Carson Smith
couldn't be more wrong
must be a canadian
Gavin Wilson
It seems like I found a huge inconsistency in your physics Veeky Forums. Impressive you could achieve a consensus on the answer
David Davis
Holy fuck/sci/, you're better than this, don't let this thread die without a proper answer
>How the hell aren't these 2 statements inconsistent? the former statement is a macroscopic statement: if you send an electromagnetic wave through some medium and measure the time it needs to cross 1 m it will turn out to be slower than when traveling vacuum. a macroscopic description is correct in saying the wave slowes down while passing through the medium. on a microscopic level it is not true: the wave never slows down BUT it is absorbed and reemitted by the molecules making up the medium. in between the electromagnetic wave is propagating with c.
Eli Campbell
>the photon is absorped and emitted by the electrons in the media so the absorption and emission are what take time? >mfw group velocity, phase velocity and drift velocity
Parker Williams
...
Carter Sullivan
I'm telling you guys, if they could just pull the answers directly out of your heads, they would NEVER pay you.
Joshua Hernandez
It's an issue simply of macro and micro. In the big picture a laser will travel more slowly through a fiber optic tube, zoom in though and the photons will travel from atom to atom at c but make be absorbed by atoms and re-emitted and reflected until they get to their destination.
Mason Wilson
I expected more from you Veeky Forums. Congratulations on passing highschool physics and looking no further.
Is the only person who is correct. The simplistic explanation is that when photons pass through a medium they interact with the charge and create a quasi particle with effective mass. Therefore the photon ceases being mass less and does not propogate at c. Asked and answered.
Jack Green
>Electromagnetism tells us that electromagnetic waves changes its velocity of propagation according to the medium it is propagating into. Correct.
>Special relativity tells us that massless particles must propagate at c Wrong. special relativity tells us that all observers agree on the velocity of things traveling at c. Classical field theory tells us that only massless things can do this, and what the value of c is. Electromagnetism is a classical field theory that predicts the value of c can vary from place to place with the presence of matter.
Angel Cooper
Jesus Veeky Forums why the fuck are you struggling with this
>1. Electromagnetism tells us that electromagnetic waves changes its velocity of propagation according to the medium it is propagating into.
The wave is always travelling at c. As was mentioned earlier in the thread the reason that it is effectively slowed is because its absorbed by the particles in the material and then remitted. This has a time dependence.
2. Special relativity tells us that massless particles must propagate at c
They do
Adam Ortiz
Its not wrong faggot, massless particles MUST travel at c, a rapid Google search will tell
Ian Moore
You have shitty reading comprehension. When I said this was wrong: >Special relativity tells us that massless things must propagate at c I wasn't referring to the fact that massless things move at the speed of light. I said you were wrong about what special relativity has to say on the matter. Special relativity is a theory of coordinates. It predicts that all inertial coordinate systems, regardless of momentum with respect to one another, will measure the speed of light to be the same. The existence of massless things and their motion is understood without the use of special relativity (Maxwell).
Special relativity is not properly equipped the talk about massless things by themselves. This is illustrated by the fact that a transformation which boosts the velocity of one coordinate system to be moving at the speed of light relative to another does not exist in the theory. The purpose of special relativity is to investigate the dynamics of massive and massless things with respect to different observers.
