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...the sensitivity of the ring interferometer to rotation arises from the invariance of the speed of light for all inertial frames of reference.
David Cooper is describing something resembling a fibre-optic "ring " interferometer ... http://en.wikipedia.org/wiki/File:Fibre-optic-interferometer.svgQuote from: wikipedia.org/wiki/Sagnac_effect ...the sensitivity of the ring interferometer to rotation arises from the invariance of the speed of light for all inertial frames of reference.http://en.wikipedia.org/wiki/Sagnac_effect
David,I'll read through this for interest, but leave comments to others as this is not my field. Just an 'off top of head' question, you say Imagine a fibre-optic cable going right round the Earth at the equator.. Why equator, why all the way round?
Just an additional though, I haven't had time to think through. When earth is moving through space as in M&M experiment the earth is not dragging any 'medium' with it, same with the train thought experiments. In the case of a cable the medium is moving, wouldn't that be the equivalent of an aether making the experiment invalid?
Thought I was a crackpot?
My off the cuff thoughts failed to think about the effect within the moving medium. However, I would have thought that the difference in time to travel around the loop is due to length contraction of the path length as seen by the photons, not a change of light speed.
David, thanks for this thought experiment. The error of thinking obviously lies in the 2nd paragraph. I like the way you have constructed this - particularly the sleight of hand distraction talking about walking round the circuit, nice touch that.
What would Einstein say next? Probably, "well that's pretty obvious, fully predicted by relativity, why would anyone think there is a problem?"
Quote from: Colin2B on 22/03/2015 10:36:27David,I'll read through this for interest, but leave comments to others as this is not my field. Just an 'off top of head' question, you say Imagine a fibre-optic cable going right round the Earth at the equator.. Why equator, why all the way round?It's just easiest to visualise it at the equator. It has to go all the way round or you won't get any results out of it.QuoteJust an additional though, I haven't had time to think through. When earth is moving through space as in M&M experiment the earth is not dragging any 'medium' with it, same with the train thought experiments. In the case of a cable the medium is moving, wouldn't that be the equivalent of an aether making the experiment invalid?I made a point of saying that you can eliminate most of the cable, but I also pointed out that the light in the cable cannot go faster than the light outside the cable, so there cannot be any dragging advantage by moving the medium._________________________________________________________Quote from: Thebox on 22/03/2015 11:49:26Thought I was a crackpot?Everyone can be a crackpot to those on the other side whenever there are incompatible beliefs involved. Some of the crackpots are right though and some are wrong, so the difficulty is in working out which side is right. What I'm trying to do here is help people question their beliefs and check to see if they're really sure of the ground they're standing on._________________________________________________________Quote from: Colin2B on 22/03/2015 15:28:11My off the cuff thoughts failed to think about the effect within the moving medium. However, I would have thought that the difference in time to travel around the loop is due to length contraction of the path length as seen by the photons, not a change of light speed.If you want to contract the length from the point of view of photons, all paths they travel are of zero length.Quote from: Colin2B on 22/03/2015 19:26:21David, thanks for this thought experiment. The error of thinking obviously lies in the 2nd paragraph. I like the way you have constructed this - particularly the sleight of hand distraction talking about walking round the circuit, nice touch that.There's no error or trickery involved in it - you've just missed the point I'm making.QuoteWhat would Einstein say next? Probably, "well that's pretty obvious, fully predicted by relativity, why would anyone think there is a problem?"That's probably not far wrong - he always was completely blind to the problem. If the speed of light is really the same in both directions at each point on the circuit relative to each point on the circuit, both pulses of light should arrive back at X simultaneously. They don't, so the speed of light cannot be the same in both directions at some of those points relative to those points. This is not an attack on relativity, but on a pointless piece of unjustifiable dogma which Einstein insisted on attaching to it when he rejected the idea of a preferred frame. A preferred frame does not destroy relativity, but simply removes some irrationality from it. If the speed of light across point X is the same relative to point X in both directions, it cannot be the same relative to point Y (on the opposite side of the planet) in both directions. You can then then switch frame and look at point Y and assert that the speed of light is the same relative to that point in both directions, but now to be consistent with this new claim you have to accept that the speed of light is no longer the same in both directions relative to point X. Einstein's walk around the planet is a journey of inconsistency in which he keeps switching frame of reference. He wants to have his cake and eat it - he wants all frames of reference to be true at the same time instead of accepting that if one of them is correct, some of the others are necessarily wrong. What he does would be equivalent to Lorentz pushing his aether theory and asserting that it doesn't need a preferred frame either - all frames of reference could then be considered to be true even though the accounts they give of events contradict each other. It is this toleration of contradiction that I object to, and I have never understood how so many intelligent people can hold such contradictions in their heads without it setting off alarm bells. The claim that the speed of light is the same in all directions is based on no evidence and which leads to an infinite number of contradictions. I don't know how anyone can stomach it.
I made a point of saying that you can eliminate most of the cable, but I also pointed out that the light in the cable cannot go faster than the light outside the cable, so there cannot be any dragging advantage by moving the medium.If you want to contract the length from the point of view of photons, all paths they travel are of zero length.There's no error or trickery involved in it - you've just missed the point I'm making.
DavidBy the time of my last post I had rejected dragging & contraction, but I was preparing supper and trying to do various other multitaskings. I'll re read your post again in light of your comments, as I say not my area so interested to learn what is happening here. Thanks againEdit: looking at my work plan, I've got a lot to fit in over the next month and I would want to add some other background reading. I'm aware of the LET/relativity duality in some areas so would want to include some of that as well. All in all will take me a few weeks to work that around everything else and do justice to the topic, but could be worth it for an interesting discussion.
David I do not wish to butt in your conversation I just wanted to point something out to you, Consider while you are observing anything, the light from what ever you are observing travels towards your eyes at a linearity and constant speed always otherwise you would not see what you were observing.Place a sweeping brush stale end by your eye, and move the brush end around in a circle.
Think bigger David, Imagine all of space is inside of a fibre optic cable and we are within the light always.
Ze cable would not be ze same as ze transparent constant, ze interference would be man made by observer effect. Ze constant in space is the same in all directions to all observers unless by interference.
Quote from: Thebox on 22/03/2015 21:19:28David I do not wish to butt in your conversation I just wanted to point something out to you, Consider while you are observing anything, the light from what ever you are observing travels towards your eyes at a linearity and constant speed always otherwise you would not see what you were observing.Place a sweeping brush stale end by your eye, and move the brush end around in a circle.That sounds like a dangerous experiment, but and a very unrewarding one too as it will not settle anything relating to the speed of light in a single direction (and probably won't settle anything relating to the speed of light at all).QuoteThink bigger David, Imagine all of space is inside of a fibre optic cable and we are within the light always.Do you mean like a fabric of space with light travelling through it? That's an interesting new idea to explore.QuoteZe cable would not be ze same as ze transparent constant, ze interference would be man made by observer effect. Ze constant in space is the same in all directions to all observers unless by interference.Ze cable in my sought experiment can be removed - it vurks wiss ze fabric of space alone (so long as it can be helped round a few corners in order to follow a circuit). Ze space fabric is ze sing zat enforces a speed limit on light in such a vay zat no photon can overtake any uzzer photon.
helping light around ze corners is interference
Having read the link from RD there seemed to be a direct analogy between the optical gyroscope and what you describe so my problem with para 2 lay in the statement"For the speed of light to be the same in both directions at all points of the cable, the time taken for it to get round the whole loop would have to be identical for the complete trip from point X back to point X in both directions,"
Do you have a different explanation of this from the LET viewpoint?
I do have a problem with ignoring the difference in speed between glass and space, but we could consider a hypothetical medium of RI=1, so that would be ok.
I have a problem with walks arounds as they can mislead us into changing FofR without realising it.
The way I visualise this is that we would now be the pivot point for a new circle with a radius replacing the roundabout's diameter. If we construct our FofR with us as the origin, one axis through the radius and the other perpendicular to that from our location we can consider the motion of the points around the roundabout.
As I've been writing this I've realised that each of the points around the roundabout, although they can consider themselves stationary relatives to a FofR, those frames will not be inertial because the frames and the points will be accelerating. What do you think?
My knowledge of SR is limited so GR is a whole new ball game. This one could take a lot longer than I thought.
PS you mention crackpots in one of your posts. Despite the tag under your name, I don't consider you a crackpot.
When you look at something moving past you, if you decide that the speed of light passing you in different directions is the same, you will naturally decide that the speed of light going past that moving object must be different in different directions for that object.
David - I've wanted for some time now to mention something to you about the threads you start. First off it appears from what little I read of them that they're well thought out. I'd love to be able to read the whole thing. However, like this thread, I find them very hard to understand. I also hate to read a post that is as long as the one you started this thread with. I'm like that with all threads, not just yours. So please don't think that since I'm not posting in these threads that I don't think what you're saying has no merit since that'd be quite untrue. It's just that it's hard for me to read posts like that. It could be because of the combination of ADD and my dyslexia. I'm not sure. Could you rewrite the opening thread in a clearer and simpler way and maybe even much shorter?Let me elaborate with an example of what I'm talking about. You start off with this:QuoteWhen you look at something moving past you, if you decide that the speed of light passing you in different directions is the same, you will naturally decide that the speed of light going past that moving object must be different in different directions for that object.I don't understand what this is saying. What do you mean by you will naturally decide that the speed of light going past that moving object must be different in different directions for that object.Can you please explain what this means and why I should naturally decide that, please? Do you mean the relative speed?
David, I was preparing this post but, PmbPhy has said something similar:I understand what you are saying but my comments were really aimed at the example you give. I don't feel it gives your assertions the support they need. ....
David - I've wanted for some time now to mention something to you about the threads you start. First off it appears from what little I read of them that they're well thought out. I'd love to be able to read the whole thing. However, like this thread, I find them very hard to understand. I also hate to read a post that is as long as the one you started this thread with.
Could you rewrite the opening thread in a clearer and simpler way and maybe even much shorter?
Let me elaborate with an example of what I'm talking about. You start off with this:QuoteWhen you look at something moving past you, if you decide that the speed of light passing you in different directions is the same, you will naturally decide that the speed of light going past that moving object must be different in different directions for that object.I don't understand what this is saying. What do you mean by you will naturally decide that the speed of light going past that moving object must be different in different directions for that object.Can you please explain what this means and why I should naturally decide that, please? Do you mean the relative speed?
I understand what you are saying but my comments were really aimed at the example you give. I don't feel it gives your assertions the support they need.
Many people will look at the fibre loop and conclude that the way it works does not support the example of light in the cable being same speed as that outside, or the same in both directions. They will then dismiss all the rest of your post despite the illogic of them doing so!
You would be better to use the mirrors example that you describe, because the speed of light is the already the same inside and outside the circuit.
I am convinced that this is not an effect of differing light speeds, but I need to try out some ideas first.