Another question that is really simple to concieve but very difficult to convey.

The best way is to use a hypothetical scenario I guess.

We have two magnets with opposite poles facing so that they are in a state of attraction. They are in a vacuum 300,000kms away from each other. There are no interferring magnetic fields.

The attraction is continuous.

WE increase the separation by 100 kms by moving one of the magnets.

The usual answer to the time the separation is experienced by our stationary magnet is 'c' so therefore the effect of change is felt approx. 1 second after the move is made. ( on the premise that 'c' is 300,000kps)

Am I correct in this assumption?


now as we are lengthening the distance we are not transmitting information, if anything we are withdrawing information.

How can it be logically stated that the stationary magnet feels no change for 1 second.?

The magnetic field is continuous. a change at one end must be felt at the other immediately. Possibly the full effect of the change may not be experienced for 1 second but surely an effect is experienced immediately.

Another scenario.

we have a pool of water. I drop a pebble in the centre of this pool, a wave ripples outwards from the epicentre. I would suggest that the outer edges of the water experience some effect immediately as all water molecules are intrinsically locked in contact with each other.

I absolutum the gradient of effect on the outer edges is small and slowly rising until the first wave hits and then we have a sharp increase in effect.

I am not sure I have communicated my question correctly so I uploaded a web page to show what I mean.

http://www.paygency.com/instantwavefront.htm

Because of the continuous relationship that pre-exists I pose that the relationship changes immediately regardless of distance. ( a small change for sure but a change regardless.

I am sure there is an easy answer to this question or is there?

Maybe some one can clear up my confusion?

The easy answer is that no, changes to the magnetic field are not instantaneous, but propogate at the speed of light. In fact, the change to the field is light in a way... I'm not well versed on the relationship between field theory and quantum particle theory, but I am of the understanding that changes to the field are mediated by the transmission of photons.

Your notion about lengthening the distance not being a transmission of information is misguided, and reveals a misconception about what is meant by the word "information".

The magnetic field is continuous. a change at one end must be felt at the other immediately. Possibly the full effect of the change may not be experienced for 1 second but surely an effect is experienced immediately.

You appear to have a strong intuitive feeling that some changes are felt immediately. Why? Why must some effect be experienced immediately?

You also seem misinformed about the way molecules are linked. Do you understand how molecules in a pool of water are linked?

Pete, firstly thank you for taking the time to post a reply, I do appreciate it. This "idea" has bugged me for ages.
You appear to have a strong intuitive feeling that some changes are felt immediately. Why? Why must some effect be experienced immediately?
Maybe another question will do:
In the case of the two magnets when pulling them apart you are pulling against something yes?
What are we pulling against?

You are pulling against a force that attracts the magnets together.

are we pulling against photons?

ok.....so we pull both magnets apart by moving both simultaneously, what is happening now?

I guess where I am stuck is that whether we move one magnet of both, which magnet has to wait for the full effect?
As the attraction is shared equally due to their relationship.

I'm fuzzy on the details, but I'll try to explain using field theory. Bear in mind that a field might not be a real thing, but something that appears to be real while it is in fact mediated by quantum thingies. I'm not sure on that part. Anyway...

Each magnet doesn't care about the other magnet. It only cares about the strength and gradient of the field at it's own location. That field dictates the forces on the magnet.

When we pull the magnets apart, they begin to move. Their movement produces ripples in the field surrounding them. These ripples propogate at the speed of light. At all times, the magnet doesn't care what the other one is doing, it only cares what the field around it looks like.

so you are saying that the magnets maintain their separate fields even though in a state of attraction. N/S

Yes. The total field is a superposition of the two fields.

so you would say that a wave front with nothing in front of it or behind it for that matter can exist?

"How can it be logically stated that the stationary magnet feels no change for 1 second.?

The magnetic field is continuous. a change at one end must be felt at the other immediately. Possibly the full effect of the change may not be experienced for 1 second but surely an effect is experienced immediately."

How is that at all logical? If the magnetic field is continuous then the effect MUST pass along the field continously- it CAN'T be instantaneous.

How fast does it travel along the field? That experiment is done all the time: An electron jumps from one energy level to another in Alpha Centauri, thus creating a "blip" in the electro-magnetic field. How fast does that blip move through the field? At the speed of light, of course, because that blip is precisely what we MEAN by light!

maybe someone could descriobe or draw how a wave front of photons would look in schematic? Showing a definitive start to the wave.

maybe someone could descriobe or draw how a wave front of photons would look in schematic? Showing a definitive start to the wave.

There is no such thing as the wavefront of photons. Photons *are* the waves and the waves *are* the photons. Sounds hairy, eh ? ;)

I don't know what your background is, but perhaps you should study actual textbooks in the field, or at least books for the layman that are detailed enough to have some of the actual theory. There is a big difference between a popular science type understanding of the topic and an actual knowledge of the mathematical theory. I make this recommendation because typically people who have actually studied the theory have fewer questions about the basic concepts, and you appear to be sufficiently interested.

If you do not do this, it seems like you may be asking questions about the basic concepts for a long, long time, which could mostly be answered by learning the actual physics.

Now , take the magnet A from this threads experiment at speed of light towards the other magnet B, as the other magnet is one light years away it wont notice the change for 1 year, But there will be a enormous magnetic tidal wave coming at it from this magnet A building up for a year . Now I would like to name that weapon as RTT Magnetic Torpedo. And when it will hit Magnet B it will get blasted with such pulling power that it will experience the madness that can exist only in todays primitive human scientist.

The existence and behavior of electromagnetic waves can be derived from Maxwell's equations. See here (http://physics.tamuk.edu/~suson/html/1402/light.html).