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Do non gravitational fields produce relativisitic effects?

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Kessy

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I know that intense gravitational fields cause relativistic effects such as time dilation and so forth, and I was just wondering if intense fields associated with the other forces can also cause these sorts of things? I don't think I've ever seen the question directly addressed, and I'm curious what current theory has to say about it, and also if it's ever been experimentally tested.
 
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SteveCNC

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Good to see you Kessy , I would be curious of that as well although my opinion is kind of already set toward thinking that time dilation and gravity are directly related to each other and you can't have one without the other .
 
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Yuri_Armstrong

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Do non gravitational fields even exist? I thought gravity was present everywhere in the universe.
 
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captdude

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There are energies associated with magnetic fields. Just as mass has potential energy when it is placed in the gravitational field of another body, a magnetic moment has an energy when it is placed in a magnetic field. This energy has many names (magnetic energy, magnetostatic energy, Zeeman energy, etc.). This energy density represents the interaction between the magnetic lines of flux and the magnetic moments of the electronic spins. This is the energy that aligns magnetic compass needles with the ambient magnetic field.

Reference from an article at http://magician.ucsd.edu/Essentials/WebBookse20.html
 
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Kessy

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Yuri_Armstrong":1f1jr3un said:
Do non gravitational fields even exist? I thought gravity was present everywhere in the universe.
Classically, a field is anything that has a particular value at every point in a given region of space. For example, you could talk about the air temperature in a room as a field. In this context, I'm talking about the strength of any of the four fundamental forces - gravity, electromagnetism, the strong and weak nuclear forces. Saying that there's a non gravitational field at a particular place doesn't mean that there isn't a gravitational field, just that there's more then one kind of field there. And you're right, gravity is present everywhere in the universe.

---

I can see an argument either way for whether you'd get relativistic effects from other fields. At the very least, I'd think finding the answer would help shed light on how and if gravity is related to the other forces. Considering that electromagnetism is both much stronger then gravity and much easier to manipulate in the lab, I'm kind of surprised no one's ever done the experiment.

One last thought - GR says that whenever you increase a body's energy, you also increase its apparent mass, right? And since all four fundamental forces have potential energy associated with their fields, shouldn't we see a change in apparent mass at the least?
 
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csmyth3025

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As I understand it the CMB is an electromagnetic field with a photon energy equivalent to ~2.7 degrees Kelvin. This field permeates the universe more or less uniformly in all directions.

Because of the equvalence of mass and energy, this field can be said to have a very small equivalent mass distributed uniformly throughout the universe and, thus, exerts a very small evenly distributed gravitational field.

I don't think this uniformly distributed gravitational field would be measurable, let alone have any sort of relativistic effects. Is this interpretation correct?

Chris
 
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origin

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Kessy":2wm8pfwm said:
I know that intense gravitational fields cause relativistic effects such as time dilation and so forth, and I was just wondering if intense fields associated with the other forces can also cause these sorts of things? I don't think I've ever seen the question directly addressed, and I'm curious what current theory has to say about it, and also if it's ever been experimentally tested.
It doesn't seem that anyone has answered the question... so, I believe the answer is no. GR indicates that the relativistic effects are due to gravity only. The strong force, weak force and electromagnetic force do not cause relativistic effects.

You do not need an 'intense' gravitational field to observe relativistic effects; the difference in gravitational strength between the surface of the earth and satelites results in easily measured relativistic effects. So it would be very simple to test this effect with an electromagnetic field. But there is no need to do the test because there is no theory or hypothesis that implies there should be an effect.
 
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ramparts

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Dryson: Yeah, Einstein wanted to make a ton of money, so he designed... erm... the single most useless theory in all of physics until GPS came along about 40 years after his death. Right. Also, what's a hootspa?

As for the OP, the answer to the question in the subject is actually technically yes, but probably not in the way the OP meant. Relativistic effects like time dilation are associated with curvature and thus, in turn, with gravity. Since other fields aren't synonymous with curvature, other fields don't have the same association with relativistic effects.

But, all fields have energy (and some even have mass), and so all fields gravitate. In theory, then, you can get non-trivial time dilation and other relativistic effects from a really strong, say, electromagnetic field; it would just have to be so strong that you'd notice the resulting spacetime curvature (which is pretty damn strong). Taking fields to be more general than just the fields causing the fundamental forces, in quantum field theory there are in fact fields for every type of particle - electron fields and the like - from which particles arise as excitations in the vacuum. These fields are quite often relativistic, and the particles you get quite often travel at relativistic speeds, so you'll get relativistic effects there.

But in no cases are the relativistic effects such a direct consequence as they are with gravity, and that's because gravity is special: it's not just any old field acting on some background, it is the background. That's what makes it so unique.
 
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csmyth3025

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ramparts":2es8c6tg said:
Dryson: Yeah, Einstein wanted to make a ton of money, so he designed... erm... the single most useless theory in all of physics until GPS came along about 40 years after his death. Right. Also, what's a hootspa?

As for the OP, the answer to the question in the subject is actually technically yes, but probably not in the way the OP meant. Relativistic effects like time dilation are associated with curvature and thus, in turn, with gravity. Since other fields aren't synonymous with curvature, other fields don't have the same association with relativistic effects.

But, all fields have energy (and some even have mass), and so all fields gravitate. In theory, then, you can get non-trivial time dilation and other relativistic effects from a really strong, say, electromagnetic field; it would just have to be so strong that you'd notice the resulting spacetime curvature (which is pretty damn strong)....
Ramparts,
I think the word Dryson meant to use is "chutzpah", which is a Yiddish word meaning (roughly) audacity or "guts". I have to agree that I can't imagine what sort of bizzaro account of Einstein's life led Dryson to conclude that he proposed Special and General Relativity
...to be walls to isolate people's minds with to herd them into harvest zones to make money off of them....
On the subject of the original post, it's my understanding that as the core of a star collapses into a black hole, its magnetic field is compressed and the temperature of the remnant rises dramatically. The greatly intensified strength of the magnetic field and of the energy represented by the remnant's temperature contribute to the gravitational field of the collapsing core. Is this correct?

Chris
 
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emperor_of_localgroup

Guest
I myself tried a crude experiment that may fall in this category.

Oneday I found myself with a Neodymium magnet and a mW laser. I focused the laser beam on a wall and brought the magnet near the beam hoping a shift of the laser spot on the wall.

Ya, sure, my 20/50 vision will detect a um (micro meter) nano meter shift on the wall.

Eventhough my experiment produced a negative result, I think, there is a possibility of deformation of 'space' by magnetic fields.
 
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Kessy

Guest
Thanks, Origins, Ramparts, for the direct answer, it was very informative. Although, Ramparts, what's always struck me as special about gravity is the fact that it operates on inertial mass, instead of a property like charge or color associated only with that force.

origin":1ndcfbbb said:
But there is no need to do the test because there is no theory or hypothesis that implies there should be an effect.
I have to say I'm a little disturbed by this part of your answer, Origin. I'm not trying to cast aspersions on anyone, but I really don't think that the statement, "There is nothing new to be discovered in physics now. All that remains is more and more precise measurement," is any more true today then it was when Lord Kelvin said it a century ago. As remarkably successful and robust as QM and GR are, they aren't a theory of everything, even taken together. And even if they were, the universe doesn't seem to feel any obligation to abide by our theories. ;) While experiments that closely follow established theory are naturally where most scientific effort goes, I think we really should make room in our philosophies and budgets for the oddball experiment, the one that's just to see what happens. After all, more then a few great discoveries were made entirely by accident.
 
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origin

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Kessy":vl9nroij said:
Thanks, Origins, Ramparts, for the direct answer, it was very informative. Although, Ramparts, what's always struck me as special about gravity is the fact that it operates on inertial mass, instead of a property like charge or color associated only with that force.

origin":vl9nroij said:
But there is no need to do the test because there is no theory or hypothesis that implies there should be an effect.
I have to say I'm a little disturbed by this part of your answer, Origin. I'm not trying to cast aspersions on anyone, but I really don't think that the statement, "There is nothing new to be discovered in physics now. All that remains is more and more precise measurement," is any more true today then it was when Lord Kelvin said it a century ago.
I didn't mean to imply that there is nothing more to discover - discoveries are made every day. I simply meant what I said. If you want to make a hypothesis that magnetism under some circustance can bend space go for it. But experiments are designed to test a hypothesis or theory why run an experiment if there is no question to answer?
 
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Kessy

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origin":7xm5do1e said:
I didn't mean to imply that there is nothing more to discover - discoveries are made every day. I simply meant what I said. If you want to make a hypothesis that magnetism under some circustance can bend space go for it. But experiments are designed to test a hypothesis or theory why run an experiment if there is no question to answer?
I think that what I'm trying to point out is that in my interpretation, there are actually two data gathering stages in the scientific method, it's just easy to overlook the first one. You make a hypothesis and then try to get data to either confirm or refute it, but before that you need some information to even frame a reasonable hypothesis. Very often that information is either something that's so much a part of ordinary experience that we take it for granted, or it's inherited knowledge. But sometimes, when investigating something we know very little or nothing about to begin with, you have to start with pure exploration - going out with honestly no real idea of what you're going to find.

In any case, there actually *is* a question to answer here. If current theory predicts that non-gravitational fields will not produce relativistic effects (aside from the sort Ramparts pointed out earlier) then that is a testable hypothesis, and an experiment that fails to find such effects would support current theory.
 
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ramparts

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Kessy, that sounds nice in theory, but you'd be surprised how coolly received a paper confirming what everyone considered to be obvious would be. That requires time, effort, and grant money.

There are really two problems: first, very few physicists want to spend time checking something like relativistic fields being associated with electromagnetic fields (which would be a) highly non-trivial to test and b) absolutely no one has any reason to expect should happen) when there's so many more interesting and relevant problems out there. The second is that by your logic, everything and anything under the sun should be "tested" (which, again, is never as simple as formulating one quick experiment, seeing something is untrue, checking off a box on your list and moving on), and at that rate nothing actually important would ever get done. There's too many things which are technically possible but extremely unlikely and not predicted by any theory to test.
 
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Jerromy

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I just had a curious thought... I wonder if any data from the LHC would disprove non-accelerative dilation? I'm assuming of course that gravitational dilation and acceleration dilation are directly related, and the LHC uses strong electromagnetic fields to keep the "trains" on track so if there were any dilational discrepancies it would be the best case scenerio to look for them...
 
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Kessy

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ramparts":xtzztdau said:
Kessy, that sounds nice in theory, but you'd be surprised how coolly received a paper confirming what everyone considered to be obvious would be. That requires time, effort, and grant money.

There are really two problems: first, very few physicists want to spend time checking something like relativistic fields being associated with electromagnetic fields (which would be a) highly non-trivial to test and b) absolutely no one has any reason to expect should happen) when there's so many more interesting and relevant problems out there. The second is that by your logic, everything and anything under the sun should be "tested" (which, again, is never as simple as formulating one quick experiment, seeing something is untrue, checking off a box on your list and moving on), and at that rate nothing actually important would ever get done. There's too many things which are technically possible but extremely unlikely and not predicted by any theory to test.

LOL Actually, Ramparts, I wouldn't be surprised *at all.* And that's kind of my point. This is my main criticism of how the scientific community does business these days. The whole system - funding, grants, publish or perish, peer review boards, and so on - has the effect of strongly discouraging anyone from venturing off the beaten path of established theory at all. And as they say, you can't discover new lands without losing sight of the shore.
 
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MeteorWayne

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That's BS. Anyone who can suggest new ideas with real science, supported with observations, models, and a reasonable explanation for the validity would be grilled, but if it stands up would be welcome with open arms.

Woo Woos that use their justification as "I think", "It seems to me", or "everything we have learned about physics in the last century is wrong because I say so" will be justifiably laughed out of the room and serious discussion unless they can support it with more than word salad.
 
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Jerromy

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MeteorWayne":3dy071og said:
Anyone who can suggest new ideas with real science, supported with observations, models, and a reasonable explanation for the validity would be grilled, but if it stands up would be welcome with open arms.
"A reasonable explanation for the validity" seems to be the jumping off point... without that we couldn't have gotten where we are. The rest is just science which has to proven fact. I'll put money on gravity and velocity being key factors.
 
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ramparts

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Kessy, you're aware that what a professional physicist thinks is a worthwhile area of research might be different from what a layman with little experience in the field thinks is, right?
 
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Kessy

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MeteorWayne":u6ez0jo3 said:
That's BS. Anyone who can suggest new ideas with real science, supported with observations, models, and a reasonable explanation for the validity would be grilled, but if it stands up would be welcome with open arms.

Woo Woos that use their justification as "I think", "It seems to me", or "everything we have learned about physics in the last century is wrong because I say so" will be justifiably laughed out of the room and serious discussion unless they can support it with more than word salad.
My comments were about how evidence is collected, not about how it's interpreted once in hand. I agree completely that ultimately it's the evidence that carries the day in forming scientific consensus. Sadly, evidence doesn't simply fall out of the sky. Well, unless you're studying meteorites, but that's another story entirely. ;) My criticism is of instances where the answer is simply assumed without making the observations to support it.

Yes, Ramparts, I am well aware that a professional scientist's opinion of what's worth investigating is likely to be different from mine. It's not my intention to wag my finger at any particular researcher, either as an individual or as part of a group, and say, "Well you should be doing experiment X! Why aren't you?" I'm just not happy when the attitude of the community seems to send the message, "Experiment X isn't worth doing, so anyone interested in it must not be a very good researcher." Scientists are as human as everyone else, and the effect on one's reputation - and possible ramifications on one's career - are certainly a consideration for anyone in choosing a research topic.

We never know what the results of an experiment will be until we actually do it, and we never know when what should be a routine experiment will turn up a completely unexpected answer. It doesn't happen all that often, but it does happen. And when it does, it can often be the doorway to a better understanding of things. Most of the time a check of something considered to be obvious will produce nothing surprising. But if we discourage people from doing those sorts of checks, we'll miss out on the occasional bizarre result.

My position is that a model should not be a prerequisite for doing an experiment. The universe is under no obligation to follow our ideas of how it should work, and it's the odd results that *don't* fit into our models that are the most interesting.

I'm not suggesting that conventional research following established theory should be abandoned, nor that scientists should be forced to do odd experiments that aren't likely to produce results. I'm just saying that if we don't make room for some unconventional projects, we run the risk of overlooking something new and exciting.

On the particular example of relativistic effects with non gravitational fields, I don't know if those effects could occur or not. You may all be entirely correct that the results would be predictable and of no interest at all. But what if they're not? What if, by some crazy chance, it turns out that those effects *do* occur? Wouldn't that be exciting? Wouldn't one result like that make a thousand fruitless experiments that just confirm what everyone already thought worthwhile?
 
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ramparts

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Kessy":1u7z8nrb said:
Yes, Ramparts, I am well aware that a professional scientist's opinion of what's worth investigating is likely to be different from mine. It's not my intention to wag my finger at any particular researcher, either as an individual or as part of a group, and say, "Well you should be doing experiment X! Why aren't you?" I'm just not happy when the attitude of the community seems to send the message, "Experiment X isn't worth doing, so anyone interested in it must not be a very good researcher."
If that's the impression you've gotten from me, then you've misunderstood me. The conclusion wouldn't be that that person isn't a very good scientist, the conclusion would be that that person either needs a better understanding of physics or has some very bizarre priorities.

Wouldn't one result like that make a thousand fruitless experiments that just confirm what everyone already thought worthwhile?
Actually, no. If for every surprise result we got, we wasted 1000 experiments for no other reason than because we could, nothing would ever get done in physics. Thankfully, we've developed smarter ways of making progress than simply trying every random experiment that comes into our heads.
 
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