Who is the dude on the right?
Without mass how could you do anything else?
Does a photon actually accelerate? Sure seems like it always goes at light speed through whatever medium from its creation.
No, they don’t. They can get absorbed and re-emitted, and the space they are moving though can compress sideways. But they can’t make curves at all.
The fact that light cannot change speed is one of the core axioms of relativity
Photons are born and die at c. They experience no time and have no frame of reference.
The speed of light is different depending on the medium though isn’t it? So to change speed I would have thought some acceleration would have to be involved.
I have no idea what I’m talking about though.
well, if it get reflected and change direction it going to be at light speed, so it can be interpreted (probably incorrectly lol) that it “accelerated instantly to the other direction after the reflection”?
This is an interesting question. Instant acceleration is mathematically implausible, but I don’t know if there’s a better physical interpretation for what happens to a bouncing photon. I’m guessing this is one of those “less particle, more wave” situations where the instantaneous velocity of the photon is undefined.
According to some random internet sources, reflection is the not-quite-instantaneous process of the photon being absorbed and then emitted by the electrons in the mirror.
As a rule, it’s probably best to avoid “random” internet sources on matters of how light works because there’s so much confidently parroted misinformation out there. For example, this is completely wrong: https://youtu.be/FAivtXJOsiI See here for correct answers to that issue: https://youtu.be/CiHN0ZWE5bk
For how mirrors work see this: https://www.scientificamerican.com/article/what-is-the-physical-proc/ https://youtu.be/rYLzxcU6ROM
There’s a hard rule about quantum physics. It goes: “it’s all fun and games until you’re at the Quantum level, then everything is all fucked up”
According to what we know, electrons don’t “move between” energy states on an electron, they’re just in one one moment and another the next. That’s so disconnected from reality we perceive it still breaks my brain.
Photons cannot accelerate
Acceleration and Velocity are vectors. Changes in a velocity vector are an acceleration. Therefore when photons change direction technically it’s a form of acceleration.
I thought photons are always moving in straight lines from their perspective, and it’s space that’s bent. Unless it’s through a medium, then they just get absorbed and re-emitted, sort of.
Space bending is a general relativity thing, which isn’t really related much to how mirrors work.
Regarding the medium bit, photons being absorbed and remitted can’t explain how light moves slower in glass. This is just an extremely popular myth. Photons are only absorbed by atoms at very specific frequencies. Also, the entire reason glass is transparent to begin with is that it’s not absorbing the photons (requires too much energy to bump the electron’s energy level so the photon isn’t absorbed and it keeps on trucking). Also photon absorption and remission is stochastic so there’s no way to control the direction it happens in or how quickly it happens. Random directions of remitted light would make glass translucent, not transparent. So for a few reasons, that’s not how it works.
Since photons are indistinguishable, it’s hard to say too much concretely, but it some sense a diffracted photon is different photon. In order for a photon to interact with say, a diffraction grating, the interaction is done with “virtual photons”.
So for a photon to change course, aka accelerate, it does it by absorbing a virtual photon and emitting another. Whether that is the “same photon” after the interaction is kinda more philosophy than physics, at least to me.
Feynman diagrams are surprisingly accessible for how much information they contain. It’s one way to think about photon (and other particle) reactions.
There is no tree level photon-photon interaction. Photons scatter off electrons (or any other charged particle), not off neutral photons.
PHOTONS HAVE MASS
ANYONE WHO DOES NOT BELIEVE THEY HAVE MASS IS A COWARD
But every time i put it on a scale, it just flys away. GIVE ME PROOF. I have a kitchen scale to offer.
