# Bremsstrahlung vs Relativity

Discussion in 'Physics & Math' started by MacM, Jan 2, 2006.

1. ### MacMRegistered Senior Member

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As I suspect most people, I have always associated Bremsstrahlung with the breaking energy release of moving charged particles.

However, a little thought opens up many questions. As the following link points out Breaking Bremsstrahlung occurs due the interaction of the EM field associated with a charged particle in motion with other particle fields.

http://www.astro.utu.fi/~cflynn/astroII/l3.html

The problem is this.

1 - If I place EM detectors around an isolated charged particle (static electricity) and then accelerate another particle then there exists a relative velocity between such particles.

According to Relativity it doesn't matter which particle we look at each now has velocity and hence should have an associated EM field.

The facts are however, that only the particle which underwent the physical acceleration (F = ma and forces) has such an EM field. The detectors around the static charge will not see any pulse of EM during the acceleration of the other particle nor any field due to relative velocity between particles.

The concept of "Relative" velocity is therefore a flawed view of motion. There exists "Apparent" motion and "Actual" motion. While it is not obvious to an observer which is which, there does exists the ability to distinguish between such types of motion and that is where SRT failed.

2 - Einstein arugued that there is total equivelence between uniform acceleration and being restrained in a accelerating gravity field.

The absence of Bremsstrahlung of static charged particles in a gravity field disputes that view.

3. ### James RJust this guy, you know?Staff Member

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35,782
Charged particles always have an associated electric field, regardless of their motion. If in motion, they also produce a magnetic field.

The detectors won't detect any change in the field from the charge which is stationary with respect to the detectors. However, they will detect effects from the charge which accelerates relative to the detectors.

How so?

I don't know what you're talking about.

That's a very rough wording of what Einstein said. I hope you understand what he said, but somehow I doubt it, since you've always had trouble coping with reference frames.

Huh?

5. ### MacMRegistered Senior Member

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10,104
James R,

If you believe you have stated something different or new here then please clarify. Otherwise you are repeating my post.

Correct. And in case you have missed it that is the point. You have actual motion and you have apparent motion. They are not the same and Relative velocity is apparent motion. The only actual motion is that which has accelerated.

No real surprise here is there?

Note:

1 - "Equivelence Principle" : Uniform acceleration and an accelerating gravity field.

Anybodyelse have trouble understanding the correlation here or is this just a James R problem?

2 - Your habit of interjecting negative innuendo when you have no physics response is well known.

See # 2 above.

Happy New Year James R.

7. ### James RJust this guy, you know?Staff Member

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35,782
But the Bremmstrahlung example doesn't show that. Does it?

Correlation between what and what? You're not being very clear.

Pardon me?

You have claimed that Bremmstrahlung somehow disproves relativity. However, your reasoning (if any) for that claim is impenetrable, as I have helpfully pointed out for you.

I suggest you try to explain yourself so people can understand what you claim is evidence for your view.

8. ### MacMRegistered Senior Member

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10,104
James R,

For anyone not already entrenched and deliberately being obtuse it is obvious that time dilation due to "Relative Velocity" is no different than Bremsstrahlung.

The only place any physical affect occurs is in the object which actually physically accelerated and is not due to relative velocity where one object may not have accelerated or moved at all. :bugeye:

If you had looked at the link I provided it would be clear:

********************** Extract ******************
1 Radiation from accelerated, charged particles

A charged particle undergoing an acceleration radiates photons.
*******************************************************
Your memory must be failing so let me remind you. You have argued that when a train accelerates away from the station that the station indeed accelerates away from the train. (I and any rational person knows better).

Last edited: Jan 3, 2006
9. ### catoless hate, more scienceRegistered Senior Member

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2,959
let me try and clarify. mac, is it your argument that one particle will produce a magnetic field and the other will not, no matter what frame of reference you choose?

10. ### GMontagRegistered Senior Member

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85
Mac, the radiation is due to acceleration *relative* to the detector. If you keep the detectors stationary relative to the other particle, you will see radiation coming from the "stationary" particle.

11. ### URIIMURegistered Senior Member

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>> The concept of "Relative" velocity is therefore a flawed view of motion.

absolutely.... The Universe is "preferred frame" referenced.
The Sun is our centre of spin, the Earth is the Moons centre

and the galactic centre is the Suns centre of spin.

12. ### MacMRegistered Senior Member

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10,104
No the frame does matter but that is where SRT fails. It holds that both have accelerated and both have velocity. Time dilation and Bremsstrahlung seem to dispute that since only the one that physically accelerates has any physical affects.

13. ### MacMRegistered Senior Member

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That is not the arguement. Read the definition again. An accelerating charged particle radiates photons. Now you want to argue that it radiates photons in one frame but not another.

14. ### GMontagRegistered Senior Member

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85
No Mac, SRT holds no such thing. SRT says that in one frame one of the particles has accelerated, and in another frame, the other particle has accelerated. Accordingly in one frame one of the particles is radiating, and in the other frame, the other particle is radiating.

15. ### MacMRegistered Senior Member

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10,104
I understand very well what relativity says. You don't seem to realize the consequences in physical terms.

Incorrect. That makes a nice rhetoric, however, you seem to forget that even in a "Rest" frame if the particle is accelerating then the EM field must be changing and any such change would be detectable in that frame.

16. ### GMontagRegistered Senior Member

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Mac, just how the hell can a particle be accelerating in its own rest frame?

17. ### PersolI am the great and mighty Zo.Registered Senior Member

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This is entertaining. After several years on this forum, MacM still doesn't understand rest frames.

I commend you for your non-conformance (even if caused by ignorance).

18. ### MacMRegistered Senior Member

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10,104

Try asking that of James R since he claims the train station accelerates aways from the train. Keep in mind that I agree that an EM detector would not measure a static field and at a given velocity (inertial) the field would be static (i.e. - equivelent to rest).

HOWEVER, that is not true of an accelerating frame. In an accelerating frame the EM field is changing and would be measureable. Otherwise no transformer would work since the secondary and primary windings are in a common frame. The changing signal in the primary is the equivelent of the changing EM field of a charged particle due acceleration.

Therefore if SRT were valid and the train station indeed accelerates away from the train and each actually has velocity such that relative velocity affects are bonafide, then a change in the EM field must become present during the "Relative Acceleration" between particles which constitute the "Relative Velocity" upon which SRT is based.

19. ### URIIMURegistered Senior Member

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729
If you wish to talk of acceleration
you can only refer it to the absolute field in that spin system.

It is meaningless to try and relate it to another body.

20. ### MacMRegistered Senior Member

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10,104
If I understand this comment I think we agree. It is meaningless to suggest that when a train accelerates aways from the station that (according to relativists) the train station is accelerating away from the train .

21. ### catoless hate, more scienceRegistered Senior Member

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I am still a bit fuzzy on the original gedanken experiment. I think you are mixing frames again.

could you explain how this makes sense? how do you accelerate and remain at rest simultaneously?

22. ### MacMRegistered Senior Member

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10,104
Certainly. The same way James R and relativists claim the resting particle has velocity without having accelerated.

I do believe you are starting to get the point.

If it didn't accelerate then it doesn't have velocity. AND if it has velocity (SRT) then it must have accelerated and hence a changing EM filed and Bremsstrahlung would have been detected.

Also, if indeed uniform linear acceleration and acceleration of gravity are "Equivelent" then static charges would be Bremsstrahlung while at rest relative to the gravitating body.

Last edited: Jan 4, 2006
23. ### GMontagRegistered Senior Member

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You're confusing issues again. The train station does accelerate with respect to the train. That's completely irrelevant in this scenario though. The thing that determines if a particle radiates or not is whether or not it accelerates with respect to the frame you are measuring from.

That's wrong. Radiation occurs when the particle is accelerating relative to the frame. It has nothing to do with whether or not the frame is inertial.

What do transformers have to do with anything in this thread?

In the frame where one of the particles is accelerating, that particle will radiate. In the frame where the other particle is accelerating, the other particle will radiate. In a frame where both are accelerating, both will radiate. There is no problem for SRT here, other than in your imagination.

It's not meaningless at all. It's just a simple fact. Acceleration is defined as change in velocity. Velocity is defined as change in displacement. The station's velocity relative to the train is changing, therefore it is accelerating relative to the train.

Where do you come up with this ridiculous ideas? This is a gedanken. The particle can start the scenario with velocity and have never accelerated. Anyway, in every frame where the particle is observed to have accelerated, radiation is observed as well. So your complaint is utterly baseless.

This is a misunderstanding of the General Equivalence Principle. It does not state that gravitation is equivalent to acceleration. It states that an accelerated frame is equivalent to a frame with a graviational field. In an accelerated frame, you still will not see radiation from a particle at rest in that frame. Accordingly, you will not see radiation from a particle at rest in a graviational frame.

Last edited: Jan 4, 2006