MPMin

Yes it does thank you

As I understand it, a magnetic field can be created by running a current through a wire and an emp can be created by pulsing a current through a wire. Aside from the duration of time between the two I don’t see any other differences. https://en.m.wikipedia.org/wiki/Electromagnetic_pulse An electromagnetic pulse (EMP), also sometimes called a transient electromagnetic disturbance, is a short burst of electromagneticenergy. Such a pulse's origin may be a natural occurrence or man-made and can occur as a radiated, electric, or magnetic fieldor a conducted electric current, depending on the source. If your view that an emp is different to a magnetic field because an emp is a segment of a magnetic field then I can see how you see them as different things an emp is a segment of a magnetic field. Here is another view. In the scenario of a wire carrying a current, before the current commences let’s assume there is nothing around the wire. When the current commences, wether the current is an alternating current or direct current, at the commencement of the current a magnetic field will populate the space around the wire starting at the wire and moving outwards from the wire at the speed of light. A direct current will produce a magnetic that doesn’t induce a current in a stationary wire but if you push the wire through that magnetic field then it will induce a current in the wire being pushed. However, On the other hand, the magnetic field from an alternating current will induce an alternating current in a stationary wire in that magnetic field. A current restive to the motion will be induced in either case the, it’s only what’s moving that is the difference. In the direct current’s magnetic field the wire has to move to induce a current and in the alternating current’s magnetic field the it’s the magnetic field that’s moving which leads me to the following analogy. If you consider a cross section view of the wire carrying an alternating current it could be viewed as dropping pebbles (to represent an alternating current) in to a pond from the top down view, where the pebbles impact the water represents the wire and the ripples represent the changing magnetic field emanating outwards from the wire. Considering that before the current commences there is nothing around the wire, but when the current commences the magnetic field be it from a dc or ac current will emanate from outward from the wire at the speed of light. In this analogy though, the water molecules are the magnetic field and the energy passing through the water molecules can be seen as the ripples. The water molecules do not move away from the centre but the water molecules do oscillate as the energy passes through them. In this analogy the magnetic field is basically a medium to carry energy. In a dc current the water would remain flat. So I can see why you say the magnetic field from a dc current doesn’t carry away any energy. Could this mean that a magnetic field from an alternating current has mass but a magnetic field from a dc current does not have mass? appogies for the font size difference I don’t know how to change the font size in this text. [FIXED]

Thank you for your detailed explanation.

I’m clearly missing something that must be obvious to you all but not me. How can a magnetic field be emitted from the wire at the commencement of the current and then stop moving while the current is still flowing? Just like the photons being constantly emitted while the current is flowing so too must the magnetic field be constantly emitted. This must be why you said a static magnetic field doesn’t carry away any energy?

Then how does the unmoving magnetic field populate the space around the wire if it’s an unmoving magnetic field?

Not even photons?

I’m I’m not being deliberately obtuse (I can’t help the way I’m sitting) and what reading isn’t clear to me. Im struggling to understand what is meant by static magnetic field. Static means stationary, constant means unchanging. You have can have a constant current but a static current doesn’t make sense because anything that flows or moves isn’t stationary or static. By static magnetic field do you mean a snap shot in time perhaps? Probably not but I thought I’d check just in case. While the constant direct current is flowing it produces a constant magnetic field around the wire, the current is constant, the magnetic field is constant and if the wire was a filament then the photons emitted would be constant too. With a constant direct current in a filament wire, Is the magnetic field being constantly emitted outward from the filament wire at the same speed and same consistency as the photons being emitted or not?

Ive always been discussing magnetic field after the current is started as there isn’t one before the current is started.

I’d like some clarity on this particular point. You say the magnetic field is circular and centred around the wire while the steady direct current is flowing through the wire. If you were to take an illustrated cross section view of the wire you could say the magnetic field appears as rings around the wire, I think we are all in agreement with this description thus far. The question is, are the rings of magnetic field stationary (fixed into position) while the steady direct current is flowing or do the rings emanate outward from the wire with new rings emerging from the wire and the outer rings get big bigger as they move away from the wire while the steady direct current is flowing through the wire?

I disagree with you on this, the magnetic field emanates out from the wire just as light emanates from a filament wire. Both light and magnetic field travel at the same speed. If you take into consideration the context i used; does any mirror reflect a magnetic field or emp the same way it reflects light? Imagine a filament wire carrying a constant direct current, the filament wire will produce light and a magnetic field, imagine the filament wire placed next to a mirror, the mirror will reflect the light but allow the magnetic field to pass through it. This would suggest that the magnetic field is independent of the photons of light. An emp is a segment of a magnetic field. This claim is based on what, exactly? It’s based on the fact that the moment the current begins to flow, the magnetic field must begin to emanate out from the wire, if it doesn’t emanate out from the wire then it must instantly appear... which it doesn’t. And if it’s does emanate out from the wire as soon as the current begins to flow then it must continue to emanate while the current is flowing. I did make these propositions hypotheticals only to illustrate a point and I did say the emitter would not absorb any photons.

Yes it does. That is exactly what it means. In this context, Is the word static being used to describe something that’s unchanging or not moving at all? If the static magnetic field produced by a wire carrying a direct current doesn’t carry away any energy is it because the static magnetic field has no energy or the static magnetic field doesn’t move away (emanate) from the wire, neither of these seem to be correct.

Thanks for your detailed answer Mordred I appreciate the detail you’ve given, I’ll go do some reading of your links you kindly provided.

I think you might have misunderstood my query. The example I used was actually for collecting photons from a source of light within the box as curiosity while on the subject of photons of . To phrase it differently, can photons be accumulated? Imagine if you could see into the box without losing any photons, would the inside of the box become brighter and brighter as the photons were being emitted inside the box because they couldn’t escape? Does this also apply to the magnetic fields of magnets?

I don’t understand your point?

I tend to disagree with you on this point, a regular mirror reflects around 90% of light but the mirror will not reflect 90% of magnetic field. A perfect reflector of light might not reflect any magnetic radiation at all but instead allow it to pass through. The above is why a magnetic field would pass through it. Just because a direct current is constant doesn’t mean the magnetic field it produces is static, the magnetic field emanates out from the wire just as light does from a filament wire.

Ok help me understand this then: if you could trap photons in a perfectly mirrored box, the box would have more mass because of the photons trapped inside, however an emp or magnetic field can pass straight through the box (because we know magnets work through mirrors) does that mean then that an emp doesn’t have relativistic mass? Further to that, if an incandescent bulb was in the perfectly mirrored box with its own power supply ( assuming the bulb and power supply did not absorb any photons and all the photons produced were perfectly reflected within the box) the magnetic field produced by the filament could pass through box but the photons could not would the box lose mass due to the magnetic field escaping the box? And if the box could perfectly trap photons, would opening the box after some time release all the trapped photons at once producing an explosion of photons so to speak or would it make no difference and opening the box after some time would look the same as opening the box at any time?

Yes though relativistic mass is replaced by variant mass in modern terminology. Both rest mass and relativistic mass originated in SR treatments where one inertial frame was considered at rest. But if relativistic mass is frame dependent how can it actually contribute gravitational mass? In different frames can an object really have different gravitational mass values?

What’s the difference though? It would seem then that GR and SR don’t agree on how to quantify mass so how do we actually quantify mass?

But when is an object ever really at rest? Does relativistic mass contribute to gravitational mass?

If you are all saying that KE doesn’t contribute to an object’s mass then m=E/c^2 should really be m=(all E except KE)/c^2

The context of this was to demonstrate that Einstein’s logic isn’t absolute.

Quoted from: https://curiosity.com/topics/the-worlds-biggest-quantum-entanglement-experiment-proved-einstein-wrong-curiosity/ The results, published in May 2018 in the journal Nature, are robust: "The observed correlations strongly contradict local realism," the authors write. Sorry, Einstein. You'll always have relativity. sorry not codependence but entanglement which is basically the same concept... No matter how you word it, this is still a user dependent point of view. Wether a reference frame is preferential or not doesn’t change the fact that a frame of reference can still be chosen at will. How is the KE being accounted for when it’s not included as part of the mass of the object and the frame of reference can be user defined? How am I saying this or even like saying this? And what’s going is only ever a clue in any case!

Einstein, apparently, wasn’t right about everything especially as you mention two photons, I seem to recall some evidence has been discovered which contradicts what Einstein said about two simultaneous photons being co dependant on each other so I think it’s fair to question even what Einstein has said in the past. I can see why KE is not classically considered to contribute to mass but I don’t agree with it. To exclude an energy because a frame of reference can’t be determined is in its self user dependant. This is exactly the same problem I had in the other thread here talking about the actual KE of an object. Just because we don’t have a universal frame of reference at this time doesn’t mean there shouldn’t be one to determine the true KE of an object. Imagine you could change your perspective to being on one of the the atoms (as if your standing on it) within an object with vibrating atoms, from that perspective you can only see the atoms in your immediate vicinity and you can’t see all the other atoms. This would seem as though the atoms you can see are all moving around randomly and there’d be no way to choose a frame of reference. In that situation you could perceive that the atom you are standing can not have its KE determined. Just because you can’t see all the other atoms of that object doesn’t mean they are isolated from everything else. It seems unintuitive to ignore some types of energy while counting the more easily quantifiable types of energy as mass contributors.

So does a magnetic field or an emp have relativistic mass?

I did, I thought my explanation of vibrational KE vs translational KE was quite clear. Im not disagreeing with E=mc^2, in fact I’m agreeing with it, I don’t see why translational KE doesn’t add to the mass of an object when vibrational KE does. I described how vibrational KE can be seen as translational KE to illustrate my point. If you’re going to say that translational KE is frame of reference dependant then that’s just another way of saying there is no way of choosing how to quantify it because we can’t decide where to look at it from but that doesn’t mean there isn’t an actual quantity to the translational KE which would add to the mass of the object. I do get to have a different point of view though, not everyone interprets information the same way. If everyone completely agreed on every aspect of science there’d be nothing to discuss.