Thread 16839889

Stupid question, but light is "electromagnetic radiation". But what part of light is "electromagnetic"? I heard it's supposed to be fluctuations of the E and B fields but I don't really understand what that's supposed to mean or if that's even right. Does it interact w/ electric and magnetic fields? If I have a really strong current or electric field, can I use it to affect the trajectory of light? I know that electromagnetic interactions are supposed to be mediated by photons but what exactly does that mean?

>>16839889 (OP)
The photon is the force carrier of the EM field. Things like magnetism, chemistry, and whatnot are downstream of light rather than light being affected by what you'd commonly call "electromagnetism."

>>16839889 (OP)
Light doesn't *have* electromagnetic fields, it *is* electromagnetic fields. What we think of as electromagnetic fields are a statistical approximation of the exchange of many discrete chunks or quanta of energy, momentum, and angular momentum from photons emitted by charged particles undergoing changes in motion or transitioning between quantum states.

>>16839925
>>16840003
>Things like magnetism, chemistry, and whatnot are downstream of light rather than light being affected by what you'd commonly call "electromagnetism."
>What we think of as electromagnetic fields are a statistical approximation of the exchange of many discrete chunks or quanta of energy, momentum, and angular momentum from photons emitted by charged particles undergoing changes in motion or transitioning between quantum states
This is the part that confuses me. Where are these photons when an iron sticks to a magnet? And are they the same as photons from a source of light?

>>16840086
They are photons with very big wavelengths (infrared photons) so you won't be able to see them the same way you see ordinary light.

>>16839889 (OP)
Dont care. Too distracted by tribal fairy

>>16840089
yeah I always like to warm my hands with the gentle glow between my two stacks of fridge magnets
do you fucking listen to yourself, retardo?
virtual photons are called virtual because they don't fucking exist

>>16840086
>This is the part that confuses me. Where are these photons when an iron sticks to a magnet?
These are not actually photons. In a calculation, they just show up as integrals. You can calculate the forces just doing the integrals, and not giving them silly names.
Feymann tried to create a human-readable narrative of what was going on, and created an equivalency between the abstract math and his drawings of diagrams with real and virtual particles, all of which are otherwise dry integrals with no name.
Strictly speaking, virtual photons are a narrative device by Feynman, the source is just a scattering calculation that requires solving the schrodinger equation for interactions.

>>16840290
This. Big mistake, OP. She's top cute.

>>16839889 (OP)
Noice.

>>16839889 (OP)
Forget about photons for now, they will just confuse you. Classically, light is a wave in two overlayed vector fields, the E field and B field (or H in this picture). A change in E (dE/dt) causes a B field, and vice versa, which allows for the propagation of waves across space. So just like water waves or sound waves, they aren't concrete objects, they are instead a wave in a field. Static charges and magnetic fields don't effect them, because they just linearly superimpose over whatever the field values at each point.

The classic sinusoidal picture of a light ray is pretty misleading for a visualization though. Those pictures are showing a 1-D wave, the other axes are the values a directions of the fields. In a real life 3d wave, they usually spread out in a sphere.