What Drives the Existence of Magnetism?

[ryanuser]

Hi, I am 15 and I got interested in this question. My question is not how magnetism exists, it is WHY magnetism exists?

Thanks

 

[Dale]

What kind of answer are you looking for? What principles are you permitting in the answer?

http://m.youtube.com/watch?v=36GT2zI8lVA&desktop_uri=/watch?v=36GT2zI8lVA

 

[micromass]

Science does not answer questions like that.

Some things to watch:

https://www.youtube.com/watch?v=E383eEA54DE

https://www.youtube.com/watch?v=KLoNA9lMb6A

 

[ryanuser]

Out of these videos and some more research, I found out that modern science cannot answer this question or physics can't answer this question at this level of undrestanding of the universe,
we possibably can answer this in the future, am I right?

 

[sophiecentaur]

Like Feynman says, the 'why' is never answerable because you can choose any level at which to answer that question. All that real Science tries to do is to describe 'how' something operates i.e to give a model which gives predictions about the way things will turn out in as accurate way as possilbe.
The answer to 'why', for early Science and Philosophy was always, ultimately "because God made it to work that way". i.e. God's Laws. That is not the approach, these days - at least not for Scientists.

 

[Nugatory]

Everyone is of course correct that science eventually runs out of answers to the infinite regression of "why?" questions.

Nonetheless, Original Poster might be interested in the way that magnetism can be made to emerge from other stuff that we accept, such as electrostatics and special relativity. Googling around for "Purcell magntism relativity" will find a bunch of good stuff, for example http://physics.weber.edu/schroeder/mrr/MRRtalk.html

 

[sophiecentaur]

Everyone is of course correct that science eventually runs out of answers to the infinite regression of "why?" questions.

Nonetheless, Original Poster might be interested in the way that magnetism can be made to emerge from other stuff that we accept, such as electrostatics and special relativity. Googling around for "Purcell magntism relativity" will find a bunch of good stuff, for example http://physics.weber.edu/schroeder/mrr/MRRtalk.html

That 'explanation' is particularly good fun, I think. A real bit of theoretical 'anarchy' to challenge what we were all taught at School.

 

[amos carine]

That 'explanation' is particularly good fun, I think. A real bit of theoretical 'anarchy' to challenge what we were all taught at School.

It's anarchy with beauty and elegance, the best type of extrapolation.

It seems to have a vast number of applications, as I'm sure the authors of that book mentioned in the link must know. The point charge in motion drawn with the field lines reminds one of a path of least resistance concept vaguely, so perhaps it can be applied to motion generically. This doesn't sound too fun, but well, the special relativity ideas are solid and worked out already. What would be really interesting would be to generalize these magnetic results of an interpretation of sr to gravity, and see what comes of it. It's a rich train of thought, how the author presented the matter.
But as to why magnetism exists, that is answered when one knows how gravity and it mix, with the rest of the factors as well. Gravity in general relativity is a geometric entity, the space pulling and pushing matter around, and the magnetic field is successful and graphic, but I think? gr is technically a field theory. So magnetism may eventually be explained in terms of geometry, with everything else (that's the big hope anyways), and then there could be some deeper reason as to why it arises, and how it relates to other entities. Talking vaguely now, there are quite a few people that think the use of probabilities, as very successfully shown by quantum experiments, is to be explained by some as yet unknown theory in which these things are not so random. Perhaps, then, magnetism and gravity are very closely related and a part of some underlying theory. If the case is that this is geometrical, then magnetism may come from those set ups, or be called for as a consequence of that relation.

 

[CompuChip]

Everyone is of course correct that science eventually runs out of answers to the infinite regression of "why?" questions.

Nonetheless, Original Poster might be interested in the way that magnetism can be made to emerge from other stuff that we accept, such as electrostatics and special relativity. Googling around for "Purcell magntism relativity" will find a bunch of good stuff, for example http://physics.weber.edu/schroeder/mrr/MRRtalk.html

Thanks Nugatory, just posting here as a reminder to study that link carefully sometime.

 

[phinds]

we possibably can answer this in the future, am I right?

Did you actually watch the Feynman video? He doesn't say we can't answer the "why" questions because we don't know enough, he says we can't answer them because they HAVE no answer in any fundamental sense.

 

[Dale]

we possibably can answer this in the future, am I right?

Not through science. Not ever.

Sometimes when someone asks "why X" they actually have a more specific and answerable question in mind, which is the reason I asked for details above. However, as posed, why questions are generally non-scientific (what test can you perform to measure "why"). Answers generally are the purview of religion or philosophy.

 

[WannabeNewton]

A real bit of theoretical 'anarchy' to challenge what we were all taught at School.

In a good number of honors EM classes for freshman in the US that is how it's taught.

 

[WannabeNewton]

Gravity in general relativity is a geometric entity...

GR doesn't explain what gravity is any more than classical electromagnetism explains what magnetism is. Just because we cast something in geometric form doesn't mean we have explained what it is, far from it. I could just as easily ask "why is gravity a manifestation of geometry?" and we would be led down the same pointless road again.

 

[Naty1]

On a somewhat positive note, electromagnetism, the strong force and the weak force have been 'unified' in the Standard Model of particle physics...that is combined into an overall mathematical framework. Off course that does not explain 'why' any are present, just some insights on how they fit together.

Offsetting that somewhat 'Pollyanna' view is that the Standard Model and it's quantum field theory falls short of being a complete fundamental theory...it's a bit of a' hodge podge' [miss mash] ...missing some ingredients like gravity, dark stuff [95% of the mass -energy in the universe] , and a lot of other basics, like the mass and charge of the electron...Is it 17 parameters that are experimentally measured rather than theoretically derived?? Something like that number.

Oh well, still lots of room for more discoveries even if 'why' eludes us.

 

[ZapperZ]

Hi, I am 15 and I got interested in this question. My question is not how magnetism exists, it is WHY magnetism exists?

Thanks

Coming back to you original question, magnetism exists because electric field exists.

Zz.

 

[HallsofIvy]

Hi, I am 15 and I got interested in this question. My question is not how magnetism exists, it is WHY magnetism exists?

Thanks

The gods of the blue continuum created "magnetism" as a weapon in their on-going battle with the gods of the red continuum!

 

[sophiecentaur]

Oh well, still lots of room for more discoveries even if 'why' eludes us.

Whether there is an ultimate answer to the "why" question is a matter of faith. It has nothing to do with Science, which, some while ago, dropped (or disconnected itself from) the idea of 'God's Laws', which are the only possible answer to 'why'.
It's quite amazing that people with religion and people without religion manage to co operate so well in Science without having to get heated with each other - whereas,in other areas of life, their ideas get in the way.

 

[rbj]

Hi, I am 15 and I got interested in this question. My question is not how magnetism exists, it is WHY magnetism exists?

Coming back to you original question, magnetism exists because electric field exists.

i think that Zapper hit it more closely than the others. the OP did not ask "why does this fundamental force we call EM exist?" but why magnetism exists. i would interpret the question as "Given that the electrostatic force exists (for reasons we know not why), why is there this additional ostensible force acting on charged particles in motion (relative to other charged particles in motion)?"

that's a legitimate "why" question and it does have an answer.

that answer is that the effects we attribute to the magnetic field in classical physics are a manifestation of the electrostatic field while taking into consideration the effects of Special Relativity. put another way, if the speed of light was infinite, SR would have no effect on what we observe and magnetic forces would not exist.

 

[jtbell]

the effects we attribute to the magnetic field in classical physics are a manifestation of the electrostatic field while taking into consideration the effects of Special Relativity.

What about the magnetic field that is associated with a time-varying electric field via the "displacement current" term that Maxwell added to Ampere's Law?

 

[rbj]

What about the magnetic field that is associated with a time-varying electric field via the "displacement current" term that Maxwell added to Ampere's Law?

how do you get that time-varying electric field?

without moving some charge around?

 

[Dale]

that's a legitimate "why" question and it does have an answer.

Which is the reason I asked the OP to clarify. There are possible answers that the OP could intend, like this one, but then again, what if the OP doesn't want to assume the electric field and relativity?

 

[ZapperZ]

i think that Zapper hit it more closely than the others. the OP did not ask "why does this fundamental force we call EM exist?" but why magnetism exists. i would interpret the question as "Given that the electrostatic force exists (for reasons we know not why), why is there this additional ostensible force acting on charged particles in motion (relative to other charged particles in motion)?"

that's a legitimate "why" question and it does have an answer.

that answer is that the effects we attribute to the magnetic field in classical physics are a manifestation of the electrostatic field while taking into consideration the effects of Special Relativity. put another way, if the speed of light was infinite, SR would have no effect on what we observe and magnetic forces would not exist.

I'm glad you saw what I was getting at, rbj. :)

The reason why I gave that answer is to figure out why the OP didn't ask "Why electric fields exists?"

Now if he/she doesn't have a problem with that, then we have our "starting point", because at some point, you have to accept something that exists (I think, therefore I am). So since he/she didn't ask about electric fields for some reason, then if it is enough that E fields exist, then this thread has been answered and we can all go home.

BTW, I'm not sure what happened to the OP. He/she hasn't come back since Aug. 17. So we may be just talking amongst ourselves here.

Zz.

 

[rbj]

I'm glad you saw what I was getting at, rbj. :)

it's nice that once-in-a-while i can post here and not get yelled at (or condescended at, or falsely accused of being or written off as an anti-science creationist - maybe i am conflating PhysicsForums with Wikipedia).

 

[rbj]

Which is the reason I asked the OP to clarify. There are possible answers that the OP could intend, like this one, but then again, what if the OP doesn't want to assume the electric field and relativity?

i look at SR as different. SR is not a fundamental interaction, but a more accurate way of looking at things.

 

[WannabeNewton]

The classical electromagnetic field is one which naturally propagates on a Minkowski background; EM is inherently relativistic and as such many aspects of electricity and magnetism are made that much clearer by just considering them in that natural relativistic framework. Purcell's EM text makes this rather evident, in my opinion.

 

[DennisN]

[...] , and a lot of other basics, like the mass and charge of the electron...Is it 17 parameters that are experimentally measured rather than theoretically derived?? Something like that number.

I don't think there's any consensus on the exact number of fundamental constants, but 17 might be too few; John Baez counts to 26 here: "How Many Fundamental Constants Are There?" (John Baez, 2011). Note: It's from 2011, so it does not reflect the Higgs detections in 2012.

 

[Dale]

i look at SR as different. SR is not a fundamental interaction, but a more accurate way of looking at things.

I didn't say that it was a fundamental interaction, but it is an essential part of the proposed answer. For that to answer the OPs question the OP must allow both the electric field and relativity as valid assumptions.

 

[fcacciola]

Not through science. Not ever.

The most--if not only--important property of the answer to a question is that it be right. And science is the method of coming up with answers for which we can measure to which extent they are correct.
If for the ideas we can get to a question there is no reasonable way to determine their certainty, then I'd say we have no answer. That is, non-verifiable responses are not an answer IMO.
Now, from this POV, I would not say "not through science" because it implies the answer might exist but science can't find it. That looks wrong: if there is an answer to be found-i.e. a response with a measurable certainty-then science can find it.

As to "not eve", well, it of course depends on the definition of "why" as well as what the OP actually meant, but, I'd like to notice that if why refers to a primary cause, then I wouldn't say never.

Suppose there is in fact a master plan for the universe, whether by God or Gods, by beings on a external dimension, by the fundamental fabric of the universe--whatever that is--acting out of authentic free-will, or something else. For as long as there might be a concrete intention, choice or will behind any process, there is no reason a priori why science can't ever find it. There is nothing intrinsically limiting science to find objectively existing things, even if they haven't been found already, and IMHO, one such thing might be the why of physical phenomena.
Granted, there might not at be any such master plan or intention, in which case there really is no why at all, but if it is, science is capable of finding it just as it is capable of telling why I write this (which is by just asking me)

That we haven't figure out a way to ask "nature" (or god, or paraphysical agents, or who/what-ever might happen to be beind all this) doesn't mean we never will.

 

[rbj]

Which is the reason I asked the OP to clarify. There are possible answers that the OP could intend, like this one, but then again, what if the OP doesn't want to assume the electric field and relativity?

I didn't say that it was a fundamental interaction, but it is an essential part of the proposed answer. For that to answer the OPs question the OP must allow both the electric field and relativity as valid assumptions.

Dale, i wasn't being critical of anyone's answer. just wanted to pick up on what Z appeared to be alluding to. (and i pretty much agree with everything you said.)

 

[MinnesotaState]

It might as well all be magic to us because our definitions don't help us much

 

[Drakkith]

That we haven't figure out a way to ask "nature" (or god, or paraphysical agents, or who/what-ever might happen to be beind all this) doesn't mean we never will.

How would you ever know that your answer is absolutely, 100%, correct?
That's what I see as the issue. You can make all the predictions you want, but you can never know whether your interpretation about what is going on is true or not.

 

[fcacciola]

How would you ever know that your answer is absolutely, 100%, correct?
That's what I see as the issue. You can make all the predictions you want, but you can never know whether your interpretation about what is going on is true or not.

Fair enough.

No doubt it is extremely useful to be able to predict with as much accuaracy as possible. In fact, all of technology is based on that. And, questions about why and, in rigor, what, are naturally outside such a "craft of prediction".

However, I don't see why we should constrain Science to only be such a craft.

The official argument (which you just presented) is that the matching ratio of predictions is the metric which allows the results of "such a craft" (I don't want to call it Science for I believe it ought to be consider a part of it) to be given a certainity. We can't be 100% sure of any physical explanation but we can be X% sure, where the fact that X is an (approximatedly) known figure what matters.

That makes sense, but so does locking up in my room because I can never know if I will be hit by a car, or some such, if I leave. So, is it really the case that Science cannot do better?

IIUC it was at the dawn of quantum physics where we (perhaps I should say you, I am not a physicist :) decided to give up and be happy with just making predictions, but, has such a position real epistemological value, or is it just a reaction to the ongoing failure to make any sense of the microscopic world? According to an article on Scientific American that I was reading last week, we don't even really know what the quantum field theory actually says, least what it means.

But, if not Science who is going to answer the fundamental question of what is really going on? it's great that we can make quantum computers, atom teleporting machines, spacetime bending warp travel ships, and all that, but that's technology and Science was never just the fuel of that.

So, what is better, not having absolutely any clue about a given thing, or having an hypothesis for which its certainity level has to be given by a metric which is not at all based on matching predictions. One which in fact cannot be related to any prediction at all?

You are of course right that all that matters is whether we know or just believe, for it is that which separates Science from everything else, but giving up on how to test it just because we haven't figure out how to do it yet, except for the narrow case of predictions against experiments, is leaving a big hole in knowledege that just can't and won't be filled by anything else.
I would argue that matching predictions cannot be the only way to asses the certainity of an explanation, and, if such a certainity can be qualified in some other way, then it is a scientific explanation.

 

[Drakkith]

I'm sorry, but I have no idea what you just said.

 

[ZapperZ]

This thread has seriously gone off-topic.

Closed, pending moderation

Zz.