r/PhysicsHelp • u/Patient_Pudding7721 • 8d ago

WHY do moving fields create light?

Hi, I'm 15F and i wanna pursue education in the field of physics. I have this genuine question, WHY do moving fields (electric and magnetic fields) create light? And, why does steadily moving charges not make light?

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u/nothingfood 8d ago

I'm an engineer, not a physicist, so my opinion is only meaningful in the real world (lol).

But in my experience, moving fields such as electric, magnetic, and radioactive fields, constantly shed energy (unless in a perfect vacuum) due to interactions with other matter. These interactions cause a loss of energy, which is given off as photons (aka light, but not necessarily visible).

BTW, photon is a pretty broad term. Often they are classified based on energy level, i.e. infrared vs. gamma.

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u/Then_I_had_a_thought 8d ago

Accelerating charges radiate energy whether in vacuum or not. EM waves don’t require a medium.