# Oscillating charged particles and E.M waves

• I
• Slimy0233
In summary, the conversation discusses the effects of oscillating charged particles and their potential to generate electromagnetic waves. It is mentioned that if a friend is tied adjacent to the oscillating particle and also oscillates in parallel, he may be able to detect the waves if the phase of his oscillation is right. However, even if his radio is disabled, he may still be able to detect the waves through other radios and using accelerometers. It is also noted that the friend can detect whether he is moving inertially or not, and therefore may expect to detect the waves.f

#### Slimy0233

TL;DR Summary
Effect of parallel motion and observation in parallel motion concerning oscillating charged particles
If I were to tie a friend of mine adjacent to the oscillating charge and make him oscillate in parallel to my oscillating charged particle such that to him the oscillating particle is at rest, would he observe the generation of electromagnetic waves.

Sure. You might make it difficult for him to detect if you get the phase of his oscillation right, but nobody else's radios are going to stop working just because you're shaking him around.

Slimy0233
but nobody else's radios are going to stop working just because you're shaking him around.
I am sorry, I don't understand this, the radios thing.

Also, I get a feeling that you are saying he would be able to detect those oscillations? I mean, it's literally at rest from his perspective. So, I was just wondering how?

I mean, it's literally at rest from his perspective.
In a frame that is accelerating...

Slimy0233
In a frame that is accelerating...
sorry Dr, but what's your point? please explain

I am sorry, I don't understand this, the radios thing.
Well, if there's a source of radio waves then radio detectors will be able to detect them. Even if your friend's radio is disabled by circumstance, he can still hear other radios detecting the waves, so he knows they're there. And he can tell he's oscillating using accelerometers, so even assuming that the oscillation disables the radio he can correct for it and make his radio inertial.
Also, I get a feeling that you are saying he would be able to detect those oscillations? I mean, it's literally at rest from his perspective. So, I was just wondering how?
You detect radio waves using the motion of electrons in a wire under the changing electromagnetic field of the wave. If you oscillate the wire I think you will cause the electrons to oscillate along with it, and they will be further accelerated by the electromagnetic field of the wave. So I think you'll still get a response from the receiver.

Remember that your friend can detect whether he is moving inertially or not in an absolute sense. So he can tell whether the charged particle holding position infront of his nose is moving inertially or not. It is, therefore, not at all obvious that he shouldn't expect EM radiation.

Slimy0233 and vanhees71
The motion of the two is presumed to be far below the speed of light so relativity does not come into it.
In this case the radiation from one, when it reaches the other, will be detectable.

Slimy0233
sorry Dr, but what's your point? please explain
You seem to be thinking that in the frame where he particle is at rest, since it is at rest and not accelerating, it cannot emit radiation. But that is only true for particles at rest in inertial frames.

Slimy0233 and vanhees71
You seem to be thinking that in the frame where he particle is at rest, since it is at rest and not accelerating, it cannot emit radiation. But that is only true for particles at rest in inertial frames.
thank you very much for explaining that.

Well, if there's a source of radio waves then radio detectors will be able to detect them. Even if your friend's radio is disabled by circumstance, he can still hear other radios detecting the waves, so he knows they're there. And he can tell he's oscillating using accelerometers, so even assuming that the oscillation disables the radio he can correct for it and make his radio inertial.

You detect radio waves using the motion of electrons in a wire under the changing electromagnetic field of the wave. If you oscillate the wire I think you will cause the electrons to oscillate along with it, and they will be further accelerated by the electromagnetic field of the wave. So I think you'll still get a response from the receiver.

Remember that your friend can detect whether he is moving inertially or not in an absolute sense. So he can tell whether the charged particle holding position infront of his nose is moving inertially or not. It is, therefore, not at all obvious that he shouldn't expect EM radiation.
hey... thank you again! that's very helpful!