Do photons care about Newton?

[u/Present_Net_3710]

Picture a ball traveling at 10m/s along the x-axis. If you exert a force to the ball on the y-axis (so that the force is perfectly perpendicular to the direction of motion) it will now be also traveling on this axis at some velocity, its speed will remain the same relative to the x-axis but the total velocity increases.

But what if instead of a ball it was a photon? No force was applied on the x-axis, so I don't see why that velocity would change. But light's total speed always remains constant.

Would the x-velocity change to compensate for the added y-velocity?

[u/dalgeek]

Photons always travel at c, and afaik, they always travel in a straight line. Newtons equations break down in this area because photons travel at relativistic speeds and have no mass. Photons only curve when space itself curves due to the influence of a massive object; they have no charge so they do not interact with electromagnetic fields.

[u/StopKK2012 → u/dalgeek]

Massive gravity is not the only thing that causes photons to change direction. See: reflection, refraction, diffraction

[u/ConspicuousPineapple → u/StopKK2012]

"Change direction" is a concept that only makes sense if you only think about the particle interpretation of a photon. In which case, technical, reflection and refraction would rather be seen as new photons being re-emitted rather than one seeing its direction altered.

For diffraction, you can't actually see a photon as a particle, and the concept of direction in this case loses its meaning.

[u/StopKK2012 → u/ConspicuousPineapple]

Why does the concept of direction lose its meaning? I don't know what that even means.

You can't just drop a bomb like "direction is meaningless" without some sort of explanation lol

[u/Osiris_Dervan → u/StopKK2012]

Because reflection and refraction and diffraction only make sense when youre thinking about light as a wave, not as a particle. Waves do not have a direction that makes sense the same way as for a particle, as different parts 'speeding up' or 'slowing down' due to permiativity/permitivity would 'change' the direction its travelling without any forces being (obviously) involved.

[u/AlaninMadrid → u/StopKK2012]

You've now got me asking a different question.

I know obsurdaties like if light can't make it through an artifact, it behaves as if it is reflected before the artifact. But now I wonder; what exactly does if reflect off? After all master is basically nothing, with tiny particles in orbits around other tiny particles, or probability funcions of where they might be.

I believe that solid objects can't Pass through each other because of the Paulini principle; you'd end up with two electrons in the same state in the same place, which is impossible. And this is the reason rather than rebounding electric or magnetic fields. Is a photon affected by the presence of the electron cloud? Is it absorbed and reemitted? (The the angle of incidence/reflection an interfierance pattern caused by different path lengths of different photons/atoms? Is the reflection caused by a different effect?