Curious45 said:
Are photons partially non-local? Warping time-space to achieve this? Seems a bit confusing.
I get that c is always supposed to be the same for all observers according to special relativity, but i am trying to picture what actually is supposedly happening there?
Forgive me if interpretation of the math/idea is either not possible, or beyond the scope of this forum. I thought there might be some kind of explanation, even if it has some math or logic component to it I don't mind...
Different scientists mean different things by "how". Some scientists like to here an explanation in terms of conservation laws, some by symmetry principles and some by forces. I am a "force" person, myself. I am satisfied by explanations in which all the forces contributing to a certain phenomena are explained. This includes the internal forces that hold the measuring instruments together. As long as the explanation has a complete inventory of the forces involved in the phenomena, I am satisfied.
There are other ways to explain "how" that are mathematically equivalent to explanations that involve force. Some scientists like explanations that involve a concept called space-time continuum. I applaud those people who can follow a theorem involving the warping of space and time. I recently tried to teach myself that type of mathematics. Although it is difficult in some ways, it has a certain charm to it. However, I feel dissatisfied with such an explanation until somebody tells me what it means in terms of forces.
When I see a theorem involving space-time, I generally do little side calculations to figure out how the forces are effected. You may not like forces in your calculations. When I give an explanation in terms of forces, you may want to rethink it in terms of space-time.
Explanations that involve forces are often self consistent in only one inertial frame. The magnitude and direction of a force may vary with the inertial frame. The timing of a specific event may vary with the inertial frame. However, the explanation is considered valid as long as it is self consistent to anyone inertial frame. There could be more than one explanation that is valid, but each has to be self consistent in one inertial frame.
Thus, I am happy with an explanation as long as it provides an inventory of forces and events that is self consistent within one inertial frame. It doesn't bother me if there is a "contradiction" in explanations given by observers in different inertial frames. It doesn't matter to me if there is "contradiction" in an explanation given by an observer who changes inertial frames in the course of the experiment. As long as I have a sequence of events and an inventory of forces that is self consistent within one inertial frame, I say it is consistent with special relativity.
A measurement of the speed of light often involves devices for measuring length, which I will refer to as rulers, and devices for measuring time, which I will call clocks. Rulers are a fixed length because the internal forces hold the atoms of the ruler together in at fixed distances. Clocks have oscillations of fixed time duration because the internal forces that make the clock works go oscillate in a certain way. In order to measure the speed of light, certain events have to be synchronized. It makes no sense to measure a distance of travel with a ruler if you don't know when the end of the ruler passes a fixed marking on the ruler. Again, synchronization usually involves some forces acting between objects. Usually, the force is electromagnetic. It could be light, radio waves, or near field electromagnetic interactions. Sometimes, the interaction can be gravitational as when one looks at the moons of Jupiter. All these ways to synchronize involve forces with a delay.
Consider an inertial frame that I will refer to as S. A ruler that is standing still in the inertial frame S has a fixed length. However, the these forces vary with the velocity of the ruler relative to the origin of S. If you accelerate the ruler to a certain velocity, the forces that hold the ruler together will get stronger in the direction of motion so that the ruler gets shorter in the direction of motion as seen by an observer in S. Similarly, a clock standing still relative to the origin sees the clock oscillate at a certain rate. If the clock is forced to move, the forces that hold the clock together change and slow the clock down. As seen by an observer in S, there are delays in the forces used to synchronize the events. All these changes in forces are self consistent to any observer restricted to inertial frame S.
Consider an inertial frame, S', that is moving relative to S. There is a ruler that is moving as seen in S. However, it is stationary with respect to S'. The internal forces that keep the ruler together as seen in S' are not the same internal forces that keep the ruler together in S. S' sees a longer ruler than S, but he sees forces consistent with this difference in length. A similar argument applies to the clocks. And to the synchronizing signals.
Thus, S and S' see a different inventory of forces. The "inconsistencies" come about only when an observer changes inertial frames. An observer can always tell when he is switching inertial frames by an "accelerometer" of some type. As long as the observer doesn't accelerate in any way, the forces that he measures will be consistent with the lengths and the time units that he measures.
Anyway, I always try to translate special relativity problems into an inventory of forces. That approach always makes sense to me. The mathematical results coming out of that result are equivalent to the results found using other starting points. So I can't claim my approach is any more "correct" than any other approach you may have. In fact, some people tell me one could have done it easier without calculating forces. That is probably true. However, if the calculated results are the same then the experimental predictions are the same. Therefore, the theory is the same. A theory is defined by its experimental predictions, not its approach.
A difference that makes no difference is no difference.
