Thread: Magnetic field lines? what are they?

*I hope that I am not embarrassing myself by posting this question in the wrong category; again*(its about photons)


I am assuming that electromagnetism and magnetism are the same thing. Are they?, if no why are they different?

1) What are magnetic field lines made of?

2) When 2 magnets interact would there be an exchange of photons between them?

3) If there is nothing there to interact with the magnet, (lets say we had placed it in a certain place in space where there is no electromagnetic force or gravity) , will there still be photons surrounding the magnet?

4) And lastly! why we don't see light around a magnet?...

I had posted a similar question earlier , but I got no response

Originally Posted by MaxPayne

*I hope that I am not embarrassing myself by posting this question in the wrong category; again*(its about photons)
....

4) And lastly! why we don't see light around a magnet?...

I had posted a similar question earlier , but I got no response

Do you know what the visible spectrum is? Is that what you mean by seeing, seeing light in the visible spectrum? If it was important to see light around a magnet biological mechanisms may have evolved to do this. I did read last year birds have little magnets in their beaks which they are able to sense and hence use these for navigation. To me that could be a form of "seeing". Sensing is seeing in a strange way. Maybe they see it? Their position might be displayed in some "map" type image in their brain as we see with our eyes. Our eyes convert light induced signals into images.

Magnetic Beaks Help Birds Navigate, Study Says I see there are other articles now disputing this study.

Originally Posted by MaxPayne

*I hope that I am not embarrassing myself by posting this question in the wrong category; again*(its about photons)


I am assuming that electromagnetism and magnetism are the same thing. Are they?, if no why are they different?

1) What are magnetic field lines made of?

Field lines have no material existence, so they aren't made of anything.

2) When 2 magnets interact would there be an exchange of photons between them?

Yes, in QED, the EM force is conveyed by (virtual) photons.

3) If there is nothing there to interact with the magnet, (lets say we had placed it in a certain place in space where there is no electromagnetic force or gravity) , will there still be photons surrounding the magnet?

Virtual photons, yes. They pop into and out of existence (this is allowed by the uncertainty principle).

4) And lastly! why we don't see light around a magnet?...

See answer to 3) above.

I had posted a similar question earlier , but I got no response

That happens to me a lot, too.

Originally Posted by MaxPayne

I am assuming that electromagnetism and magnetism are the same thing. Are they?, if no why are they different?

I missed this part earlier. In a sense they are the same, but in common usage, they are treated differently. "Electromagnetism" (which we'll take to mean "electromagnetic force") is the general term, and "magnetism" (magnetic force) is a specific aspect of it. Electric and magnetic forces are frame-dependent quantities, so what is an electric force in one frame can appear as a magnetic force in a different one (and vice-versa).

Originally Posted by tk421

Originally Posted by MaxPayne

3) If there is nothing there to interact with the magnet, (lets say we had placed it in a certain place in space where there is no electromagnetic force or gravity) , will there still be photons surrounding the magnet?

Virtual photons, yes. They pop into and out of existence (this is allowed by the uncertainty principle).

I've been told that this view is not quite correct, that charges and magnets don't spray out virtual photons willy-nilly, and that the only virtual particles are the ones that are involved with the interaction in accordance with Feynman diagrams.

Originally Posted by KJW

I've been told that this view is not quite correct, that charges and magnets don't spray out virtual photons willy-nilly, and that the only virtual particles are the ones that are involved with the interaction in accordance with Feynman diagrams.

I'm sorry that my terse answer allowed for an interpretation that willy-nilly spraying was occurring. I interpreted the OP's question about "nothing there to interact with the magnet" to mean "nothing else besides the magnet is there to interact with the magnet." The field between the poles of a magnet is generated by the interaction of virtual photons, fully in accordance with Feynman diagrams.

Originally Posted by KJW

I've been told that this view is not quite correct, that charges and magnets don't spray out virtual photons willy-nilly, and that the only virtual particles are the ones that are involved with the interaction in accordance with Feynman diagrams.

Please tell me if the following ideas are wrong.

* Bodies interact with each other through forces.

* Electromagnetic force is conveyed through virtual photons.

* If a charge is not spraying out virtual photons all the time, how does it come to know that there is another charge in its vicinity and so it needs to exchange photons with it.

* If the particle already knew that there was another particle there, then there should have been some sort of interaction going on between the charges even before they started exchanging photons. but we can't call it a force either....So is it spooky action that makes this possible?

I hope I can help a little, Max!

Originally Posted by MaxPayne

Please tell me if the following ideas are wrong.

1. Bodies interact with each other through forces.

2. Electromagnetic force is conveyed through virtual photons.

3. If a charge is not spraying out virtual photons all the time, how does it come to know that there is another charge in its vicinity and so it needs to exchange photons with it.

4. If the particle already knew that there was another particle there, then there should have been some sort of interaction going on between the charges even before they started exchanging photons. but we can't call it a force either....So is it spooky action that makes this possible?

1. is certainly correct, but a word such as "force" is also subject to slippery definitions. Much physics is contact physics, but not all physics e.g. gravity and quantum entanglement.

2. Is an invention of modern (i.e. SR-tainted) quantum theory. Virtual photons are a mathematical abstraction, hence you have already seen the duplicity lying in assertion 3!

4. There is undoubtedly spooky action at a distance between particles i.e. instantaneous action at a distance as demonstrated by the Aspect Experiment, quantum signalling and gravity. The attempts of the doubters to contrive alternatives e.g. virtual photons, stretching space etc. are concepts that lead to infinite regress and logical paradox, ultimately reducing to intellectual schlock!

So I always emphasize Max, we MUST work backward from observed data, not just "logically forward." Working thru backward inference we can establish what are the fundamental philosophical and physical grounds to establish the correct philosophical dogmas on which to base physics. This has not been done by the physics community, and its relevance is expressly denied by modern physics. However, the questions YOU ask, MaxPayne, are not ones that modern physics can answer correctly - as you can already see. Like you, I do not like so-called scientific theories to lead to logical paradoxes!

TFOLZO

So I always emphasize Max, we MUST work backward from observed data, not just "logically forward."

Very true, No "theory" is Universal... But it would be wrong to say that a "theory" is completely wrong, there are some observations which don't agree with "da theory", but there are also a lot more of them which seem to agree with it.
It just need some tweaking thats all....

I don't think it will be great idea to throw it all away and start from a time when earth was flat and was the center of the Universe.

What do you think?

I got mad at that person who told me that we are actually living on the surface of the earth and not inside of it.

Originally Posted by MaxPayne

Please tell me if the following ideas are wrong.

* Bodies interact with each other through forces.

I prefer to think of it as an exchange of energy-momentum.

Originally Posted by MaxPayne

* Electromagnetic force is conveyed through virtual photons.

It may be that virtual particles are nothing more than a mathematical notion associated with the way the interaction is calculated.

Originally Posted by MaxPayne

* If a charge is not spraying out virtual photons all the time, how does it come to know that there is another charge in its vicinity and so it needs to exchange photons with it.

* If the particle already knew that there was another particle there, then there should have been some sort of interaction going on between the charges even before they started exchanging photons. but we can't call it a force either....So is it spooky action that makes this possible?

One way that this might viewed is to consider that of all the seemingly possible spacetimes, the only ones that are actually possible are the ones in which the photons have both a definite start point and a definite end point.

Yes, this is "spooky action at a distance" similar to that of quantum entanglement. But a charge doesn't have to "know" about the other charge because we are dealing with a global consistency of an entire spacetime, the inconsistent spactimes simply being excluded from existence.

In so many cases, as you say, a theory cannot be completely discarded but is merely modified by further theories. E.g. the notion of continental drift was rejected for inadequate reasons then came back as the new theory of plate tectonics.

Originally Posted by MaxPayne

Very true, No "theory" is Universal... But it would be wrong to say that a "theory" is completely wrong, there are some observations which don't agree with "da theory", but there are also a lot more of them which seem to agree with it.
It just need some tweaking thats all....

I don't think it will be great idea to throw it all away and start from a time when earth was flat and was the center of the Universe.

What do you think?

I got mad at that person who told me that we are actually living on the surface of the earth and not inside of it.

Well if we define the earth's surface as the solid & liquid surface we could actually claim that they live inside the earth since a house or cave could be construed that way. Likewise if we include the gas envelope of our atmosphere - we would then be well inside the earth's gassy surface!

You are certainly right in that we don't have to go back to a flat earth which is also treated as the center of the universe.

But this is because we just go back to Galileo - all motion is relative - who also taught that the universe is infinite and the earth NOT its centre. Nor did he believe the Sun to be the center either. If we begin with Galileo we will get somewhere!

TFOLZO

Originally Posted by TFOLZO

If we begin with Galileo we will get somewhere!

I think modern physics actually does begin with Galileo. It just doesn't end there.

Originally Posted by TFOLZO

But this is because we just go back to Galileo - all motion is relative - who also taught that the universe is infinite and the earth NOT its centre. Nor did he believe the Sun to be the center either. If we begin with Galileo we will get somewhere!

TFOLZO

So, according to you, I could break the light barrier just by flashing a torch while jogging. thats too easy.

Well if we define the earth's surface as the solid & liquid surface we could actually claim that they live inside the earth since a house or cave could be construed that way. Likewise if we include the gas envelope of our atmosphere - we would then be well inside the earth's gassy surface!

You are certainly right in that we don't have to go back to a flat earth which is also treated as the center of the universe.

But this is because we just go back to Galileo - all motion is relative - who also taught that the universe is infinite and the earth NOT its centre. Nor did he believe the Sun to be the center either. If we begin with Galileo we will get somewhere!

TFOLZO[/QUOTE]

Actually I thought that the earth was hollow and we lived inside it.

Originally Posted by KJW

I prefer to think of it as an exchange of energy-momentum.

It may be that virtual particles are nothing more than a mathematical notion associated with the way the interaction is calculated.

Yes, I agree with you. But then again the energy gets transferred as discrete pulses, not as a continuous flow from one particle to another.

One way that this might viewed is to consider that of all the seemingly possible spacetimes, the only ones that are actually possible are the ones in which the photons have both a definite start point and a definite end point.

But a particle interact(either gravitationally or Em) with almost all other particles in the space(T/F). It has to throw out "virtual" photons in every direction, because in every direction will be particles with whom they are interacting with, no matter how far away they are in space. Only way to stop two particles from interacting is to displace them in time so that the force never reaches it's destination.

Yes, this is "spooky action at a distance" similar to that of quantum entanglement. But a charge doesn't have to "know" about the other charge because we are dealing with a global consistency of an entire spacetime, the inconsistent spactimes simply being excluded from existence.

Isn't it the curvature of spacetime that is making it self consistent?


What would happen if we align three electrons in a straight line? Will the third one experience the same force due to the first one? Same in the sense the same photons/pulses given out by the first electron.
If the second electron couldn't shield the third electron from forces of the first electron completely.
a) It is because of quantum non locality of the said particle.... that allows "force" to go right through it.
b) It is because the second electron absorbs all the energy then re transmits the excess energy to the third one....if this is the case we will be able to measure a time delay.
c) It is not virtual particles that are transmitting the force, it is the spacetime itself using one or more of it's smaller hidden dimensions.


So in short my point is this: if a particle don't have to know where the other particle is located in space to interact with it. It must be throwing out "pulses of energy/ virtual particles" in every direction. Why is it not the case?

Originally Posted by KJW

I think modern physics actually does begin with Galileo. It just doesn't end there.

And Galileo was never wrong, he talked about relative motion of particles. He never considered light as particles.
SR is only an addon to the Galilean Relativity not a replacement.

Originally Posted by MaxPayne

And Galileo was never wrong, he talked about relative motion of particles. He never considered light as particles.
SR is only an addon to the Galilean Relativity not a replacement.

I think if Galileo had lived in Einstein's time, he would've formulated special relativity. I think he came quite close anyway, but the intellectual and technological environment of his time was not mature enough for him to take the step of including time in his relativistic picture of the world.

Originally Posted by MaxPayne

But a particle interact with almost all other particles in the space. It has to throw out "virtual" photons in every direction, because in every direction will be particles with whom they are interacting with, no matter how far away they are in space.

It may be true that there will be a particle in all directions, but this doesn't mean that a particle sprays out virtual particles willy-nilly, hoping for the best.

Originally Posted by MaxPayne

Isn't it the curvature of spacetime that is making it self consistent?

I'm not sure what you mean. General relativity is a purely classical theory and as such, it cannot explain "spooky action at a distance".

Originally Posted by MaxPayne

What would happen if we align three electrons in a straight line? Will the third one experience the same force due to the first one? Same in the sense the same photons/pulses given out by the first electron.
If the second electron couldn't shield the third electron from forces of the first electron completely.
a) It is because of quantum non locality of the said particle.... that allows "force" to go right through it.
b) It is because the second electron absorbs all the energy then re transmits the excess energy to the third one....if this is the case we will be able to measure a time delay.
c) It is not virtual particles that are transmitting the force, it is the spacetime itself using one or more of it's smaller hidden dimensions.

Virtual particles aren't required to travel in a straight line. A virtual particle travels all possible paths in quantum superposition with interference between the various paths. A virtual particle also doesn't have the same restrictions as the corresponding real particle. For example, a virtual particle can be "off shell", which means they can have any mass (it also means they are not limited by the speed of light, and this includes virtual photons)

Originally Posted by MaxPayne

So in short my point is this: if a particle don't have to know where the other particle is located in space to interact with it. It must be throwing out "pulses of energy/ virtual particles" in every direction. Why is it not the case?

Because consistency of an entire spacetime is a global notion, not a local notion. Consider the Aspect experiment. The two entangled photons are correlated even though they don't have a definite polarisation. Measuring one photon determines the other photon even though it may be far away. The correlation is the result of the creation of the entangled pair but is maintained as a result of global consistency. When one photon is measured, this global consistency guarantees the result of the other photon without requiring this photon to "know" the outcome of the measurement. It works because the inconsistent pairs of results are simply not part of the quantum superposition and have zero probability. It is global in that the quantum superposition is of global (two-particle) states.

It may be true that there will be a particle in all directions, but this doesn't mean that a particle sprays out virtual particles willy-nilly, hoping for the best.

Why?

I'm not sure what you mean.

Sorry, I wasn't clear there.
Due to curved nature of spacetime, there is no possibility of photons moving out of it, and not find an end point.

General relativity is a purely classical theory and as such, it cannot explain "spooky action at a distance".

Actually I feel , we haven't yet developed the "Spooky Action at a distance" plugin for GR, thats all. Once it is achieved we could actually play spooky action in Relativity,
just like the "time is relative concept" developed a century ago.

Virtual particles aren't required to travel in a straight line. A virtual particle travels all possible paths in quantum superposition with interference between the various paths. A virtual particle also doesn't have the same restrictions as the corresponding real particle. For example, a virtual particle can be "off shell", which means they can have any mass (it also means they are not limited by the speed of light, and this includes virtual photons)

Any mass? I thought virtual particles like photons and gravitons had no mass. Can you please elaborate on that? I am hearing this for the first time.

Because consistency of an entire spacetime is a global notion, not a local notion.

Originally Posted by MaxPayne

Why?

Because virtual particle paths have definite start and end points, This could not be guaranteed if they were sprayed out willy-nilly.

Originally Posted by MaxPayne

Due to curved nature of spacetime, there is no possibility of photons moving out of it, and not find an end point.

The universe is generally regarded as being infinite

Originally Posted by MaxPayne

Actually I feel , we haven't yet developed the "Spooky Action at a distance" plugin for GR, thats all. Once it is achieved we could actually play spooky action in Relativity,
just like the "time is relative concept" developed a century ago.

Just as the double-slit experiment cannot be explained in classical terms, general relativity cannot describe it either, due to the same limitations.

Originally Posted by MaxPayne

Any mass? I thought virtual particles like photons and gravitons had no mass. Can you please elaborate on that? I am hearing this for the first time.

We don't know if gravitons even exist. I don't think they exist. As for the photon, it is the real photon that has zero mass. In calculating the force, there is a contribution from every path of the virtual photon in the quantum superposition. This even includes paths that a real photon could not take. It includes energy and momentum values that do not correspond to zero mass. This is what is meant by "off shell" (the shell being the set of points in energy-momentum space corresponding to a particular mass). This is fine because virtual photons are not real particles. They are not constrained in the same way as real particles. They are never observed and any violation of the laws of physics is perfectly hidden and never appears in the real particles of the system. That is, the change in energy-momentum of one real particle corresponds to the change in energy-momentum of the other real particle, and what happens between the two real particles is quantum uncertainty.

Originally Posted by MaxPayne

Suppose that there are two straws: a short straw and a long straw. You pick one but don't look at it. I am left with the other but don't look at it. It's ten years later and you'd moved to the other side of the world. I look at my straw. It's the short straw. Therefore, even after ten years and thousands of kilometres away, I know you have the long straw. I don't have to see your straw or interact with it in any way. In other words, even though each of us had a 50% chance of having either straw, there was no chance that we would have the same straw. Of each of the combinations of straws:

short short
short long
long short
long long

the short short and long long combinations were inconsistent and excluded from the reality, even though the straws were separated by thousands of kilometres. It doesn't matter how far apart the two straws were because the entire universe that contains me with a short straw and you with a short straw simply doesn't exist. However, before I looked at my straw, I didn't know if I was in the universe containing me with a long straw and you with a short straw. When I looked at my straw, that entire universe was excluded too and you immediately had the long straw. There was no local transmission of information because the consistency between our two straws was global.

I should stress that this is an entirely classical picture, but it does explain the nature of the consistency required by quantum mechanics even though it doesn't address the aspect of quantum mechanics that cannot be explained classically, which is that I didn't have the short straw until I actually looked at it, and not when you drew your straw in the beginning.

This thread was about magnetic field lines!

So MaxPayne, in order to understand them better you need to read Hannes Alfven's Nobel Prize Lecture and work from there - in order not to get yourself frozen up in frozen-in field lines. The abstract frozen-in magnetic field lines are the magnetohydrodynamic (MHD) equivalent of Einstein-Minkowski worldlines, the latter applying to 'material points' rather than fluids.

TFOLZO

Originally Posted by MaxPayne

*I hope that I am not embarrassing myself by posting this question in the wrong category; again*(its about photons)


I am assuming that electromagnetism and magnetism are the same thing. Are they?, if no why are they different?

1) What are magnetic field lines made of?

2) When 2 magnets interact would there be an exchange of photons between them?

3) If there is nothing there to interact with the magnet, (lets say we had placed it in a certain place in space where there is no electromagnetic force or gravity) , will there still be photons surrounding the magnet?

4) And lastly! why we don't see light around a magnet?...

I had posted a similar question earlier , but I got no response

I am assuming that electromagnetism and magnetism are the same thing. Are they?, if no why are they different?
-In special occasions, you may say so.

1) What are magnetic field lines made of?
-Oh You can imagine they are made of a kind of special small balls.

2) When 2 magnets interact would there be an exchange of photons between them?
-You can imagine that the photons are balls made of the same material, whatever their size, color or quality. When 2 magnet interact, the balls sent from each magnet interact only, but not exchange.

3) If there is nothing there to interact with the magnet, (lets say we had placed it in a certain place in space where there is no electromagnetic force or gravity) , will there still be photons surrounding the magnet?
-Yes, a magnet sent balls from its toe to its head, recycling. But most of magnets will lose their balls as time passes by, except some so-called "permanent magnets" made majorly from rare-earth elements, like neodymium magnets.

4) And lastly! why we don't see light around a magnet?...
-Because you are not at a proper speed to watch the balls move. Now Einstein should jump out to aid you.

Reading through this thread, I feel like it would be good to just start over.

Originally Posted by MaxPayne

*I hope that I am not embarrassing myself by posting this question in the wrong category; again*(its about photons)


I am assuming that electromagnetism and magnetism are the same thing. Are they?, if no why are they different?

1) What are magnetic field lines made of?

A magnetic field is caused by a changing electric field. So, we need to know what an electric field is first.

So, what is an electric field? An electric field is much like a gravitational field, except it surrounds charged objects, and it is caused by the objects' charges, not their mass.

Whenever the electric field begins to get stronger or weaker, a magnetic field forms. For example if a charged particle is moving away from you, the strength of the electric field near you will begin to diminish (because the particle is getting further away.)

There is a lot more to discuss about question #1, but I'll wait and see if you ask any sub-questions.

2) When 2 magnets interact would there be an exchange of photons between them?

Yes.

3) If there is nothing there to interact with the magnet, (lets say we had placed it in a certain place in space where there is no electromagnetic force or gravity) , will there still be photons surrounding the magnet?

I'm going to say..... yes.

4) And lastly! why we don't see light around a magnet?...

I had posted a similar question earlier , but I got no response

The light emitted by a typical magnet is extremely low frequency. Lower than the human eye can see.

Indeed, usually it is lower than any device other than a few really expensive military devices would be able to pick up.

I'll volunteer my answers. The questions are in bold:

I am assuming that electromagnetism and magnetism are the same thing. Are they?, if no why are they different?

Magnetism is a subset of electromagnetism, that's all.

1) What are magnetic field lines made of?

Nothing, because they're abstract things that don't actually exist.

2) When 2 magnets interact would there be an exchange of photons between them?

No. QED talks of virtual photons, but these aren't actual photons, they're "field quanta". Like you divide the field up into chunks and say each one is a virtual photon. See Matt Strassler's article: "A virtual particle is not a particle at all. It refers precisely to a disturbance in a field that is not a particle..." Also see near and far field on Wikipedia: "In the quantum view of electromagnetic interactions, far field effects are manifestations of real photons, while near field effects are due to a mixture of real and virtual photons". Then see Evanescent modes are virtual photons. The evanescent wave is a standing wave. You divide it up into little chunks and say each one is a field quantum. Then it's like these virtual photons are the accounting units for your calculations. Like pennies are the accounting units of your financial calculations. When you pay a cheque into your bank account, there isn't some hailstorm of real pennies flying into a bank vault. In similar vein there aren't any real photons flying around a magnet.

3) If there is nothing there to interact with the magnet, (lets say we had placed it in a certain place in space where there is no electromagnetic force or gravity) , will there still be photons surrounding the magnet?

No. It is surrounded by its field.

4) And lastly! why we don't see light around a magnet?...

Because there isn't any. Remember this: hydrogen atoms don't twinkle, and magnets don't shine.

Originally Posted by tk421

Virtual photons, yes. They pop into and out of existence (this is allowed by the uncertainty principle).

That argument assumes that the so-called Heisenberg Time-Energy Uncertainty Principle (TEUP) licenses the violation of the conservation of energy long enough for a virtual particle to make its appearance and then disappear. However that argument is based on a common misconception, the misconception that you can use the TEUP that way, which you can't.

Originally Posted by tk421

I am assuming that electromagnetism and magnetism are the same thing. Are they?, if no why are they different?

Electromagnetism is a field of study based on Maxwell's equations while magnetism is a physical phenomenon that includes forces exerted by magnets and currents on other charges, magnets and currents.

See
Electromagnetism - Wikipedia, the free encyclopedia
Magnetism - Wikipedia, the free encyclopedia

Farsight -- please correct your citation. You have me saying things I did not say (the second "quote" from me is not from me).

How are virtual photons different from real ones?...

Originally Posted by MaxPayne

I am assuming that electromagnetism and magnetism are the same thing. Are they?, if no why are they different?

No. They are not. To see the exact difference please see

Electromagnetism - Wikipedia, the free encyclopedia
Magnetism - Wikipedia, the free encyclopedia

To be specific, paraphrasing Wikipedia, Electromagnetism, or the electromagnetic force is one of the four fundamental interactions in nature, while magnetism is a class of physical phenomenon that includes forces exerted by magnets on other magnets. Magnetism is a subset of electromagnetism.

The electromagnetic force F_m exerted on a charged particle is given by

F_m = q[E + vxB]

Originally Posted by MaxPayne

01) What are magnetic field lines made of?

Magnetic fields don't have a real existence. See Q & A: Magnetic Field Lines Don't Really Exist | Department of Physics | University of Illinois at Urbana-Champaign

Originally Posted by MaxPayne

2) When 2 magnets interact would there be an exchange of photons between them?

Sorry but that subject can only be addressed through quantum field theory. Since I've never formally studied it I choose not to comment on it.

Originally Posted by MaxPayne

3) If there is nothing there to interact with the magnet, (lets say we had placed it in a certain place in space where there is no electromagnetic force or gravity) , will there still be photons surrounding the magnet?

Same response as I gave in question 2. However since you're talking about virtual photons which are only exchanged between two particles I imagine the answer is no.

Originally Posted by MaxPayne

4) And lastly! why we don't see light around a magnet?...

Why would you expect to? There are virtual photons all over the place between electrons in atoms and you don't see those, do you?

Originally Posted by MaxPayne

How are virtual photons different from real ones?...

Real photons can be observed, virtual photons can't. Virtual photons can have non-zero rest mass while real photons never have rest mass.

The only difference between the electric and magnetic fields is the coordinate system of the observer. This inspired Einstein to propose the theory of relativity.

If I am stationary next to a charge I will measure an electric field. if I a moving relative to it I will measure some field and some magnetic field. As I move faster the electric field becomes weaker and the magnetic field stronger.

Hi physicist;
Can they have any mass?..If they have mass then it would mean that the range of electromagnetism isn't infinite?

If I am stationary next to a charge I will measure an electric field. if I a moving relative to it I will measure some field and some magnetic field. As I move faster the electric field becomes weaker and the magnetic field stronger.

Why does this happen?

Originally Posted by MaxPayne

Why does this happen?

Why does a static charge create and electric field and a moving one create a magnetic field? Is that what you mean?

Originally Posted by MaxPayne

Hi physicist;
Can they have any mass?..If they have mass then it would mean that the range of electromagnetism isn't infinite?

Real photons have zero mass while virtual photons can have non-zero mass.

Note Virtual particle - Wikipedia, the free encyclopedia

Virtual particles do not necessarily carry the same mass as the corresponding real particle, and they do not always have to conserve energy and momentum, ....

I snipped the rest because I don't think what follows on that page is accurate.

Originally Posted by Physicist

Real photons have zero mass while virtual photons can have non-zero mass.

Note Virtual particle - Wikipedia, the free encyclopedia

I snipped the rest because I don't think what follows on that page is accurate.

Physicist, you are right to leave it there, the page has issues. Wiki does not seem to be able to distinguish short-lived particles which you can detect from virtual particles which you cannot.

Originally Posted by Jilan

Physicist, you are right to leave it there, the page has issues. Wiki does not seem to be able to distinguish short-lived particles which you can detect from virtual particles which you cannot.

Actually which photons are virtual and which aren't is not an easy thing to determine. Griffiths text on particle physics talks about this. Would you like me to direct you to that book? You can download it off the web. Can you read PDF files over 10MB?

Thanks physicist, that would be great.

Originally Posted by Jilan

Thanks physicist, that would be great.

The text is called Introduction to Elementary Particles by David Griffiths. You can download it off the internet from Introduction to Elementary Particles | David Griffiths | digital library BookOS

I've done this quite often with many textbooks. You can easily use Elmer's glue to bind the pages together. I use two steel plates on one end and then clamp them together with two
clamps and use a cover with something like a very sturdy paper, almost cardboard. It works wonderfully!