Le Repteux

Only data are facts, the rest is imagination. Pot, kettle, black: remember?

I understand what you mean Studiot, but I am sure that if we discussed your point in details, it would not work either. If the world goes round, it is not because of simultaneity, it is because of interactions. Bodies do not mind about what is happening elsewhere, they mind about what is happening right now, and right now for them as far as light is concerned is when it is perceived, whatever the motion of that body.

He only claims that the mind experiment in question does not explain the real observations that we make, not that the data from these observations are false. I agree with him, whatever the way you turn that mind problem around, there is no way out, so why not admit that there might be something that we do not understand about motion yet?

You elude the fact that Christopher does not seem to find a way to convince others either. Scientific method demands that we are as objective as possible, which means that we have to do the effort of considering both point of views in a discussion. I have observed this effort in Christopher's posts, but not in yours. When all the possible arguments have been presented and people still disagree with the conclusion, the best way to close the subject is to "agree that we disagree", as Christopher pointed out, not to blame the other camp of being wrong, as you do here.

I bet Chris does not answer you because Einstein did not talk about other universes in his mind experiment. Do as you ask others to do Studiot, stick to Einstein's specifications!

If you do a real experiment, how can you be sure that the two flashes of light are simultaneous if you do not have a precise clock at each end of the train? This mind experiment needs clocks, exactly like GPS does. With pre-synchronized clocks, you know the emitted frequency, and you can calculate the distance at each second, so you have the speed. No need to ask ourselves if the signal is simultaneous for all observers, we know it is. Very good arguments! I will try them next time you say something else than "nope".

Hi Phy, How much for the publicity you just gave me? (Thats a joke! I got the message, which is very easy to understand by the way, compared to mine!) I am trying to make up a point to begin with, the stuff around it will come later when you decide to feed it. Take two synchronized atomic clocks, put them at the two ends of the train, and let the two observers measure their frequencies: there will be no doppler effect for the observer on the train, but there will be some for the observer on the embankment. Do the contrary, put the two atomic clocks on the embankment: there will be no doppler effect for the observer on the embankment and some for the observer on the train. You see, when we only observe the frequencies, there is no contradiction. But the only way to produce precise frequencies at different places is to use synchronized atoms, and we can do so because we discovered that atoms stay synchronized. Now, if we can observe that atoms are synchronized, don't you think that atoms themselves already can? And if we can use that property of them, as for using the Positioning System to move precisely from one point to another for example, don't you think that they also could if the could move by themselves? For example, how do you think that the atoms of the moon can accelerate towards those of the earth so precisely that, from second to second, they compensate exactly for their orbital velocity? How could they do that without using their own timing system?

It is relevant if we consider that a mind experiment with two atoms and their background would be equivalent to the mind experiment with the train and its embankment. Ah, this is probably where you were getting at. Of course, I knew about that equivalence, but I probably do not know it in detail as you may do. I know about all the main principles, but I learn the details when I need them, which is mainly to answer to objections about my ideas not corresponding to the actual theories. Instead of trying to understand others' ideas, we too often oppose them our own ones, because we cannot believe instantly to what is new, which is a good thing, otherwise there would be no evolution since there would be no resistance to evolution, thus no continuity. Did you have a look at this other subject of mine on mass? Does it interest you? http://www.scienceforums.net/topic/83590-look-ma-no-maths/ What about this other one on mind? http://www.scienceforums.net/topic/83736-look-ma-no-mind/

Because these properties of space usually concern macroscopic scales. Yes I did. And since virtual photons cannot exceed the speed of light, do you agree that this limit has to apply to the way atoms will measure their reciprocal motion when part of a molecule?

Studiot, Yes, until the small steps are established, I take for granted that space is isotropic and homogeneous for two atoms using light as a guide to execute them. Does that help you to accept them as a possibility?

I did ask for more information, I asked you to enumerate the principles that you wanted me to comment, but I still do not see what you want to do with that information.

How do you think that atoms have been able to keep their frequencies all those billions of years. If you let go two atomic clocks without connecting them, they will get out of sync quite quickly, but if they stay connected, they will stay sync forever. An important principle of physics is that phenomenon are interconnected, I suggest that this interconnection helps the atoms to stay sync with all the other atoms of the universe, and that their mass appears when they get out of sync, which happens during an acceleration.

I cannot see what you are getting at, this is probably why my answer was not satisfying to you, but I still don't, so I guess you will not like this answer either. For the purpose of my thesis on mass, apart from resistance to acceleration, the only principles that I retain are doppler effect and atoms of the same kind emitting the same frequencies, which is what an atom needs to stay synchronized with another one. Principles about space are irrelevant to atoms: what they see is what they get. If you want more information about what I take for granted or not in physics, ask more precise questions, enumerate the principles and I will tell you which one I retain.

As you may have noticed, I am not discussing the data from relativity, I am only discussing the mind experiments. What is fundamental is that the information we get from our experiments, where light is emitted from a real source and strikes a real instrument of measure, is restricted to the speed of light. Even if we can imagine the trajectory of light in a drawing, we can only measure it with a signal that cannot exceed the speed of light. Looking at a drawing, we can imagine simultaneity, but it is physically impossible to measure it with an experiment. This is why I suggest that discussions about those experiments will always lead to contradictions. Since I understand the maths, I know that it is not because people do not understand them that they do not agree with the outcome of the experiments, so to me, the only answer to those long discussions is because mind experiments with light naturally induce contradictions. But those contradictions do not evacuate the fact that light exchanged between bodies in motion necessarily induces relativistic effects in their motion. What I suggest is to look more closely at what atoms face when trying to stay synchronized with other atoms, because they have the same problem that we have with our mind experiments about light, and they seem to have solved it a few billion years ago.

Discussions here about the mind experiences of Realivity probably count hundreds of pages, with no satisfaction on either camp. If it was so evident, somebody would have found the link between the camps. It is not evident, and some scientists even say that you need to understand the maths to understand the theory. This is not true, if a theory cannot be explained with words, maths won't help. We have to look somewhere else than where we already have. Why not take a look at what atoms see when light strikes them? We cannot measure an experiment about the speed of light with an information that does not travel faster than light, it is physically impossible. We have data that proves GR works because atoms can keep their frequency all by themselves, but if it was not the case, we could not use them to measure time and the GPS could not help us with our light experiments. In fact, it is not a light experiment that we make, but a timing experiment, and this is also what I think the atoms do with light.

Mind experiments with light will always induce contradictions, because in the reality, we cannot perform them. To experiment with sound, we can use light, and it works because the information we get goes faster than the information that produces the phenomenon we observe, but nothing goes faster than light, so we cannot experiment with it, we can only observe the phenomenon. To me, this means that, apart from participating to life process, or from helping us to produce energy, light has another purpose than the one we use to take for granted, which is to give us, humans, information about what is going to happen to us.

Unless you are so certain to be right that you cannot realize that this person knows what you are talking about, you cannot educate somebody about something that this person knows, you can only try to convince him that you are right. I bet you do not agree with the canceled doppler effect for two observers in the same moving reference frame, is that so? If xyzt leaves, we will have more time to talk about that, but I bet he won't. Oups, sorry xyzt, I made a mistake as usual. What you noted in red should be written: "he will measure their frequency to be the different if the source and the receiver in co-motion emit the same frequency"

To xyzt, Considering that the source and the receiver are co-moving means that an observer at rest can measure their co-motion, and if this observer is motionless in the middle of the two light flashes, as the one on the embankment, he will measure their frequency to be different. On the other hand, considering that the doppler effect at the source is canceled by the doppler effect at the observer means that we cannot measure our own speed if we observe the light emitted by sources in the same reference frame as ours, which is exactly what we observe. Molecules that carry the sound waves on a train are in inertial motion, but not the space that carries the light waves. Got a better example? Also, maths does not prove that a theory is right, it only proves that it fits the data obtained from our observations. By the way, do you also believe that Relativity theory will last forever?

As far as physics is concerned, I prefer to observe phenomenon than to observe humans. You are assuming too much about what I know, and not enough about what I propose. Once we assume that a body is motion, we must assume that doppler effect is present, otherwise it creates contradictions. If a reference frame is in motion, it produces doppler effect, because it is then de facto constituted of bodies in motion. Relativity is about inertial motion, it does not permit us to determine which body is in motion with regard to another one, and this produces contradictions in the mind experience of the train and the embankment. It simply does not work to assume that it is impossible to determine which one is in motion. We have to find another way around, and to do that, the small steps that I propose is interesting, because it explains inertial motion in an unexpected way. Have a look at them and try to determine if they contradict the data. Discussing theories does not mean that we did not study them, it means that we noticed their limit and that we think they can be improved. Do you think that relativity will last forever?

If relativity was so straightforward, it would not be discussed that much. There are contradictions, and we must find why. No, but proposing solutions does. Since the train moves, there is doppler effect at both ends, but it cancels out. There is no mirror in Christopher's first mind experience, and this is the one that I am talking about. Theories pass, data stay. Theories will stay when the world has been completely explored, which shall never happen if it is infinite.

Hi everybody, I agree with Christopher, even if observations prove that the numbers from relativity formulas are right, the mind experiments on which the theory rests contain contradictions. To me, the main reason is because light was not originally useful for us to measure motion, but for particles of matter to measure their own motion and to use that information to move properly one before the other . More precisely, I think that bodies in inertial motion rely on the limited speed of light to keep moving at the same pace, and that they rely on its timing to resist a change in direction or in speed. (see here) In the mind experience above, it is not the time of arrival of the light flashes that would be important for the particles, it is their frequency. If the flashes are emitted from the train, for the observer on the train, the frequencies would be the same because the doppler effect at the source is canceled by the doppler effect at the observer, and for the man on the embankment, the frequencies would be different because of the doppler effect at the source. If the flashes are emitted from the embankment, for the observer in the train, the frequencies would be different because of the doppler effect at the observer, and for the observer on the embankment, they would be the same because there is no doppler effect. Observing the frequencies directly does not create contradictions, but observing a mind experience as if the light emitted from every thing we imagine struck our eyes at the same time does. The only way to experiment with light is when it hits our instruments, and a ray of light traveling before our eyes in a mind experiment does not hit our eyes. If it is so, you may say, why do we observe relativistic effects? Because, if particles use the information from other particles to move with respect to them the way I suggest they do, since their motion cannot exceed the speed of their information, the frequency and the direction of that motion is subjected to relativistic effects.

On second thought, make it one part Skeptic134 and two parts xyzt please, Swansont.

Hey Swansont, in my martini, I will take one part of xyzt and two parts of Skeptic134 please.

What is the difference between a frequency synthesizer and the electronic device that is actually used to incorporate the corrections sent from the ground or made before launching?

This is effectively another way to the same question, but that question is just a curiosity to help understand relativity, it is not a relativity issue.