owl Posted March 1, 2011 Share Posted March 1, 2011 Good. Thank you. I should have been more specific. If everyone in the thought experiment thinks like you do and believes like you believe then they all agree on the position of everyone at the end of the hour, yes? Let me do a graphic: At t = 0 everyone agrees this is everyone's position as well as the position of the rods, yes? At t = 1 hour everyone agrees that this is everyone and everything's position, yes? Is that correct? Yes. Both are at the end of their rods, and I am about at the end of my patience with this pedantic little exercise of yours. Why don't you just make your case from beginning to end? I really don't see the point in belaboring it all, like, "If everyone in the thought experiment thinks like you do and believes like you believe..." Of course they don't. But I don't know what other people believe.... 'cept that rod length changes with velocity of observer, etc., which I consider absurd. (No doubt that "observed rod length changes." Link to comment Share on other sites More sharing options...
Iggy Posted March 2, 2011 Share Posted March 2, 2011 Yes. Both are at the end of their rods That was not the question. I really don't see the point in belaboring it all, like, "If everyone in the thought experiment thinks like you do and believes like you believe..." Of course they don't. But I don't know what other people believe I am not asking what possible beliefs the stick figures might have. I am showing that your beliefs are inconsistent. To do this you must assume that all of the people in the thought experiment are using your system of mechanics (absolute space, time, and present). If I ask "do they all agree on the location" you cannot answer "No, I don't think everyone will agree, because some of you believe in length contraction". That is a non-answer. Saying "I don't know what other people believe" is not an answer to "If everyone in the thought experiment thinks like you do and believes like you believe then they all agree on the position of everyone at the end of the hour, yes?". It is not an answer to that question. There is a reason why this question is specifically important. If you cannot answer it then we cannot continue. If everyone in the thought experiment thinks like you do and believes like you believe then they all agree on the position of everything at the end of the hour, yes? Link to comment Share on other sites More sharing options...
IM Egdall Posted March 2, 2011 Share Posted March 2, 2011 I think all the arguments with Owl could be resolved with the facts from actual experiments. But here's the problem. We have all kinds of evidence with atomic clocks on airplanes, rockets, and satellites and numerous laboratory experiments that time does indeed slow down with motion, and in the amount predicted by Einstein's special relativity formula. But the evidence for length contraction is indirect. I know of no direct measurement verifying length contaction. I'd be thrilled to learn that I am wrong. Link to comment Share on other sites More sharing options...
DrRocket Posted March 2, 2011 Share Posted March 2, 2011 I think all the arguments with Owl could be resolved with the facts from actual experiments. But here's the problem. We have all kinds of evidence with atomic clocks on airplanes, rockets, and satellites and numerous laboratory experiments that time does indeed slow down with motion, and in the amount predicted by Einstein's special relativity formula. But the evidence for length contraction is indirect. I know of no direct measurement verifying length contaction. I'd be thrilled to learn that I am wrong. There was an experiment being planned about a year ago, I think it was to be the first direct measurement of length contraction. The trick is to make two sinultaneous position measurements of a rapidly moving object. I have not heard anything further. Link to comment Share on other sites More sharing options...
owl Posted March 2, 2011 Share Posted March 2, 2011 That was not the question. I am not asking what possible beliefs the stick figures might have. I am showing that your beliefs are inconsistent. To do this you must assume that all of the people in the thought experiment are using your system of mechanics (absolute space, time, and present). If I ask "do they all agree on the location" you cannot answer "No, I don't think everyone will agree, because some of you believe in length contraction". That is a non-answer. Saying "I don't know what other people believe" is not an answer to "If everyone in the thought experiment thinks like you do and believes like you believe then they all agree on the position of everyone at the end of the hour, yes?". It is not an answer to that question. There is a reason why this question is specifically important. If you cannot answer it then we cannot continue. If everyone in the thought experiment thinks like you do and believes like you believe then they all agree on the position of everything at the end of the hour, yes? "What we have here is a failure to communicate"... ('Cool Hand Luke'.) I misunderstood what you meant by: "To do this you must assume that all of the people in the thought experiment are using your system of mechanics (absolute space, time, and present" I thought everyone contemplating your thought experiment on these boards were, "all of the people in the thought experiment." Way off, as I see now. Par for the course with our communication. So its about the stick figures believing as I believe! Well, that makes it easier. They will come to the end of their rods in the same hour, having each traveled 540 million miles. You hammer on... "If everyone in the thought experiment thinks like you do and believes like you believe then they all agree on the position of everything at the end of the hour, yes?" Yes, of course. They are my clones in your little skit here! My wrong assumption above threw me way off track. So, now we can proceed with the inquisition. But, to define terms, I differ with the usual (relativity) meaning of "absolute space, time, and present." The most simple meaning of space (before the post-Euclidian revolution) was emptiness... nothingness, no "thing" at all... not some "absolute" like the old "aether" (ether) or whatever. But I suspect that this version of space is just too simple to understand! We just *must* make "something" of it! Time, is no "thing" either, as I've argued to death on these boards. The present being always present is very hard to argue with, but many do. Or they think "time" is some kind of local "environment," even though it's all about clocks' variation in rate of "ticking" or "time keeping." Now everywhere is obvious. No argument with the fact that "it takes time" for light/information to travel from one place to another. Just to keep clear on definitions. Link to comment Share on other sites More sharing options...
DrRocket Posted March 2, 2011 Share Posted March 2, 2011 Forgive me for I have sinned in that I do not accept everything about relativity as absolutely true! You have spoken Ex-Cathedra as a True Believer in the doctrine of relativity. Anyone questioning the dogma is a heretic and a fool. You don't even bother to engage in the conversation enough to address the specifics in my last post. Oh well. I see new developments on the horizon in which good ol' Euclid might find a new respect among relativity theorists, but you will not be among them. Your mind is made up, and you are not about to waste your time with a fool like me. Such fundamentalism right here in science! One thing that should be abundantly clear is that you are ill-equipped to determine what I think. My mind is most certainly not made up, nor in my experience is that of any other professional mathematician or scientist. There is no such thing as dogma in science and questioning current theory is the essence of research. You are correct in only one regard; there is indeed no point in wasting time with a fool. Link to comment Share on other sites More sharing options...
Iggy Posted March 2, 2011 Share Posted March 2, 2011 I thought everyone contemplating your thought experiment on these boards were, "all of the people in the thought experiment." Way off, as I see now. Understood. You hammer on... "If everyone in the thought experiment thinks like you do and believes like you believe then they all agree on the position of everything at the end of the hour, yes?" Yes, of course. Good. Thank you. Only two more questions then. If they shoot a laser to the right at the onset, then after an hour everything is positioned like this? Do each of our thought experiment cosmonauts agree that this is the position of everything? Link to comment Share on other sites More sharing options...
owl Posted March 2, 2011 Share Posted March 2, 2011 Yes. Link to comment Share on other sites More sharing options...
Greatest I am Posted March 2, 2011 Share Posted March 2, 2011 Well we can't know it, but we can come up with something we are very sure is the answer. If we lived near the edge of the known universe, perhaps, but from here, we cannot see far enough and thus, recognizing our limmits in terms of travel time in the universe, we will never likely prove whatever theory we come up with. Regards DL -1 Link to comment Share on other sites More sharing options...
owl Posted March 2, 2011 Share Posted March 2, 2011 While we are waiting for Iggy to proceed with his agenda, I will again address the ontology of "time," specifically as asserted by I Me as a well proven entity, as follows: "We have all kinds of evidence with atomic clocks on airplanes, rockets, and satellites and numerous laboratory experiments that time does indeed slow down with motion" We KNOW that clocks "tick" or "keep time" differently in all kinds of different inertial/energy/gravitational environments. But you again repeat the litany that "time does indeed slow down with motion." Do you see the ontological fallacy of this often repeated assumption, asseting that time is an entity that slows down/speeds up? Link to comment Share on other sites More sharing options...
Iggy Posted March 2, 2011 Share Posted March 2, 2011 (edited) Yes. Good. At t=0 the distance between the light and all three people is zero At t = 1 hour the distances are The distance between the left guy and the light changes 1210 million miles in one hour. He finds the speed of light to be 1210 million miles per hour. The distance between the center guy and the light changes 670 million miles in one hour. He finds the speed of light to be 670 million miles per hour. The distance between the right guy and the light changes 130 million miles in one hour. He finds the speed of light to be 130 million miles per hour. By assuming that distance, time, and simultaneity are constant (in other words, those things are the same for all observers) we have found that the speed of light is not constant (it is not the same for all observers). Since you have said that you believe the speed of light is constant you should see that you are contradicting yourself. The speed of light actually is constant in all inertial reference frames. The first good indication of this was with the Michelson–Morley experiment in 1887. They assumed the world worked the way you described it and the way I drew it in the diagram. If the speed of light is c for one person then it would be c-v for another person who is moving with a speed v in the direction of the light. In other words, if Leonardo (the guy in the middle of the diagram) figures that light is moving to the right at 670 million mph and there is another guy floating to Leonardo's right at 540 million mph then the guy on the right would figure that the distance between the light and himself changes 130 million miles in one hour. That is what the diagram shows and it is intuitive. What they found instead is that light moves at c for anyone in any inertial reference frame. It is invariant and constant. The guy on the right finds that the distance between the light and himself changes 670 million miles in one hour. Albert Einstein explained the constant speed of light by making distance and time variable in special relativity. The invariant speed of light and the predictions of relativity are confirmed accurately and regularly with things like GPS. In other words, you say that everyone in the diagram will agree that the distance between the guy on the left and the laser beam changes 1210 million miles in one hour. If fact, the guy on the left should find that the distance changes 670 million miles in one hour. Edited March 2, 2011 by Iggy Link to comment Share on other sites More sharing options...
michel123456 Posted March 3, 2011 Share Posted March 3, 2011 (edited) I stopped at the first sentence. The distance between the left guy and the light changes 1210 million miles in one hour. He finds the speed of light to be 1210 million miles per hour. No. He is not there to measure that. The only way he can do to measure the speed of light is to put a mirror where the red arrow is, and wait for light to reach him back. The light will have traveled 670 miles to go to the mirror 670 miles to come back at origin. 540 miles to go left Total 1880 miles in time: 1 hour to go 1 hour to come back at origin 0,8 hour to go left (approx 540/670=0,8059) Result 1880 miles/2,8 hours = 670 miles/hour Now the second sentence: The distance between the center guy and the light changes 670 million miles in one hour. He finds the speed of light to be 670 million miles per hour. Most probably, but he doesn't know that either. The only way to know is with a mirror, see above. He will get the expected result. Third sentence: The distance between the right guy and the light changes 130 million miles in one hour. He finds the speed of light to be 130 million miles per hour. No. Again he doesn't know that. He has to put a mirror where the red arrow stands. He will measure: distance for light 670 miles to go 130 miles to come back to him (670-540=130) total 800 miles time for light 1hour to go 0,2 hour to come back (approx 130/670=0,194) total 1,2 hour result 800/1,2=666 miles/hour approx 670 miles/hour. Elementary Newtonian calculations. All 3 observers will get the correct result. By assuming that distance, time, and simultaneity are constant (in other words, those things are the same for all observers) we have found that the speed of light is not constant (it is not the same for all observers). Since you have said that you believe the speed of light is constant you should see that you are contradicting yourself. No. See above. Sorry Owl far having responded in your place. ----------------------------------------- I really wonder how dumb you think we are. ----------------------------------------- You should ask yourself how dumb we think you are. ------------------------------------------ Sorry, I am pissed for other reasons. Edited March 3, 2011 by michel123456 Link to comment Share on other sites More sharing options...
Spyman Posted March 3, 2011 Share Posted March 3, 2011 Michel you are pissed off, missing the point and doing the elementary Newtonian calculations wrong. I suggest you take a break and come back when you have calmed down. Either Giovanni, Leonardo and Raphael agrees that everything are as showed in Iggy's image after one hour or they don't. Link to comment Share on other sites More sharing options...
Iggy Posted March 3, 2011 Share Posted March 3, 2011 (edited) Sorry, I am pissed for other reasons. No trouble mate. He is not there to measure that. I agree. The only way he can do to measure the speed of light is to put a mirror where the red arrow is, and wait for light to reach him back. While I think it would cloud my point, I don't think there would be any conceptual problem extending the thought experiment that far. The distance between the left guy and the light changes 1210 million miles in one hour. He finds the speed of light to be 1210 million miles per hour. The light will have traveled 670 miles to go to the mirror 670 miles to come back at origin. 540 miles to go left Total 1880 miles in time: 1 hour to go 1 hour to come back at origin 0,8 hour to go left (approx 540/670=0,8059) Result 1880 miles/2,8 hours = 670 miles/hour If the guy on the left were stationary relative to the guy in the center then I would agree. When the light reaches 540 million miles left of origin the guy on the left wouldn't be in that spot any more. The easiest thing to do is to describe the extended thought experiment from the center person's frame then do Galilean transforms to move to the other frames. Assuming the mirror is stationary in the center person's frame, it would end up being that the light is detected by the guy on the left 10.3 hours after it is emitted (in both frames). The light would travel a total of 6.90615 x 10^9 miles in the center frame and 2.420 x 10^9 miles in left frame. I really wonder how dumb you think we are. Like I said earlier I don't believe you are dumb. I wouldn't have a problem telling you otherwise if I thought otherwise. Edited March 3, 2011 by Iggy Link to comment Share on other sites More sharing options...
michel123456 Posted March 3, 2011 Share Posted March 3, 2011 (edited) I really apologize Iggy. You behaved correctly all along. I didn't. Mea culpa. Edited March 3, 2011 by michel123456 2 Link to comment Share on other sites More sharing options...
IM Egdall Posted March 3, 2011 Share Posted March 3, 2011 (edited) The speed of light actually is constant in all inertial reference frames. The first good indication of this was with the Michelson–Morley experiment in 1887. I disagree. As I have said in earlier post, Michelson-Morley experiment failed to find the ether that was believed to be the medium for conducting EM radiation. But it said nothing one way or the other about Einstein's light postulate: the speed of light being constant in all inertial frames. The experiment was done in only one inertial frame (the Earth.) Well an approximately inertial frame. Anyway, the light source and the detectors of that light were at rest with respect to each other. So only one inertial frame. So not a test of Einstein's light postulate. Edited March 3, 2011 by I ME Link to comment Share on other sites More sharing options...
owl Posted March 3, 2011 Share Posted March 3, 2011 I'll take this one step at a time, and then you can tell me where exactly I get derailed. First, I am not debating SR, but rather arguing that local frames of reference do not describe the global reality of the situation. (All quotes, Iggy.) "The distance between the left guy and the light changes 1210 million miles in one hour. He finds the speed of light to be 1210 million miles per hour." The guy on the left has gone 540 million miles in the opposite direction from the light beam. Their speeds are not cumulative, as I said in a previous post where I fired two lasers, left and right, each independent of the other, each going, obviously at "C", not twice "C." So your last sentence above is false. His observation does not "see" the global picture. "The distance between the center guy and the light changes 670 million miles in one hour. He finds the speed of light to be 670 million miles per hour." Yes. "The distance between the right guy and the light changes 130 million miles in one hour. He finds the speed of light to be 130 million miles per hour." No. If he were firing the light beam as he traveled (540 million miles an hour") it would only gain 130 million mph, the difference between his speed and lightspeed. I covered this also in a previous post with a rocket man going nearly lightspeed firing a laser straight ahead. Same result as above. "Light can not be pushed and faster than "C." (I pondered why in same post.) Since the light beam and he started from center at the same time, they are independent velocities, his at 540 and light, as always, at 670 (million mph.) "By assuming that distance, time, and simultaneity are constant (in other words, those things are the same for all observers) we have found that the speed of light is not constant (it is not the same for all observers). Since you have said that you believe the speed of light is constant you should see that you are contradicting yourself." As above, I am not assuming that at all. Rather independent velocities, since the guy on the right, going 540, is not the light source. "The speed of light actually is constant in all inertial reference frames. The first good indication of this was with the Michelson–Morley experiment in 1887. They assumed the world worked the way you described it and the way I drew it in the diagram. If the speed of light is c for one person then it would be c-v for another person who is moving with a speed v in the direction of the light." So, again, you misunderstand the way I think the "world works." Here it is again, frames of reference (FOR) claiming to be the ultimate perspective on the global (overall) situation described*. "FOR observer A vs FOR observer B." * Left guy went 540 million miles to "the end of his rod" in an hour. Right guy did the same in the opposite direction. Light, from origin at center, went right 670 million miles in the same hour, going 130 million miles further than right guy. What left or right guy "sees" does not change what I just said, nor is the constancy of lightspeed violated. "In other words, if Leonardo (the guy in the middle of the diagram) figures that light is moving to the right at 670 million mph and there is another guy floating to Leonardo's right at 540 million mph then the guy on the right would figure that the distance between the light and himself changes 130 million miles in one hour. That is what the diagram shows and it is intuitive." Right guy, from global perspective, would notice that light went 130 million miles further than he did in the hour. No problem. "What they found instead is that light moves at c for anyone in any inertial reference frame. It is invariant and constant. The guy on the right finds that the distance between the light and himself changes 670 million miles in one hour." See my last comment, same application here. Light traveled at 670. He traveled at 540. Light went 130 further. He was confused. "Albert Einstein explained the constant speed of light by making distance and time variable in special relativity. The invariant speed of light and the predictions of relativity are confirmed accurately and regularly with things like GPS." I am not questioning the predictions of relativity for differences in FOR! I am saying that any overview, transcending local FOR will still have constant lightspeed without the absurdity of changing distances to accomodate the differences between what observer A and observer B "sees." Earth-sun distance, as I have already beat to death, does not vary with... what observer A and observer B "sees." "In other words, you say that everyone in the diagram will agree that the distance between the guy on the left and the laser beam changes 1210 million miles in one hour. If fact, the guy on the left should find that the distance changes 670 million miles in one hour. " Again, he had an independent journey to the left. He ends up 1210 million miles from the end locus of the light beam at the end of the hour without the absurd assertion that it traveled 1210 million mph. Maybe this makes no sense to you. Maybe it clarifies. What do you think? Link to comment Share on other sites More sharing options...
khaled Posted March 3, 2011 Share Posted March 3, 2011 I'm not a physician, but I have read a book on Relativity ... There is a case that makes me more confused than anything else I thought of about Light ... Assume a train that travels in the Speed of Light, and that the train has front-lights, also, assume there are two persons inside the train at its both ends facing each others, and the person who stands at the back of the train holds a light-bulk ... I have simple questions: 1. will the front-lights of the train lights leave its light-bulbs ? 2. will anyone be able to perceive the train front-lights ? 3. will the light of the light-bulk held by the person inside the train travels through the train to the other end ? 4. can the person in the other end of the train perceive the bulk-light ? 5. what happens to both light bulbs after a time, in that particular case ? I can't even imagine ... Link to comment Share on other sites More sharing options...
Iggy Posted March 4, 2011 Share Posted March 4, 2011 (edited) The speed of light actually is constant in all inertial reference frames. The first good indication of this was with the Michelson–Morley experiment in 1887. I disagree. As I have said in earlier post, Michelson-Morley experiment failed to find the ether that was believed to be the medium for conducting EM radiation. But it said nothing one way or the other about Einstein's light postulate: the speed of light being constant in all inertial frames. It was an indication. The experiment was done in only one inertial frame (the Earth.) Michelson and Morley expected to get different results at different times of day and different times of year because the equipment changed reference frame as earth rotates and orbits the sun. Because the equipment did not give different results in different reference frames, it indicated that an invariant speed of light was a possibility. "In other words, you say that everyone in the diagram will agree that the distance between the guy on the left and the laser beam changes 1210 million miles in one hour. If fact, the guy on the left should find that the distance changes 670 million miles in one hour. " Again, he had an independent journey to the left. He ends up 1210 million miles from the end locus of the light beam at the end of the hour without the absurd assertion that it traveled 1210 million mph. Maybe this makes no sense to you. Maybe it clarifies. What do you think? If you are floating in space and you shoot a laser and 1 hour later it is 1210 million miles away then the laser light is receding from you at a velocity of 1210 million mph. Assume a train that travels in the Speed of Light Do you mean at the speed of light or under the speed of light? Edited March 4, 2011 by Iggy Link to comment Share on other sites More sharing options...
DrRocket Posted March 4, 2011 Share Posted March 4, 2011 The experiment was done in only one inertial frame (the Earth.) Well an approximately inertial frame. Anyway, the light source and the detectors of that light were at rest with respect to each other. So only one inertial frame. So not a test of Einstein's light postulate. The Earth is not an inertial reference frame, though it is a fair approximation over short time intervals during its orbit around the sun.. The Michelson-Morley experiment was repeated at different times of the year and by various experimenters over a period of years -- different reference frames. http://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/morley.html#c2 Link to comment Share on other sites More sharing options...
Spyman Posted March 4, 2011 Share Posted March 4, 2011 (edited) (All quotes, Iggy.) ... "The distance between the right guy and the light changes 130 million miles in one hour. He finds the speed of light to be 130 million miles per hour." No. If he were firing the light beam as he traveled (540 million miles an hour") it would only gain 130 million mph, the difference between his speed and lightspeed. I covered this also in a previous post with a rocket man going nearly lightspeed firing a laser straight ahead. Same result as above. "Light can not be pushed and faster than "C." (I pondered why in same post.) Since the light beam and he started from center at the same time, they are independent velocities, his at 540 and light, as always, at 670 (million mph.) I wonder if you understand what you are saying? You are claiming that Raphael, the guy going right, is measuring the speed of light to be 130 million mph relative him because he is already moving at 540 million mph through space! Do you claim that the surface of Earth is fixed firmly in space or do you accept that we are moving through space? Because IF your claim are correct and we are moving through space then we would measure different speeds of light depending on Earths position and speed in our orbit arund the Sun. This has been tested and falsified, measurements of the speed of light is always 670 million mph relative the observer, independent of the speed through space. If Leonardo would continue to send out more light pulses with his laser then both he and Raphael would independently measure the speed of light to be 670 million mph relative themselves. "The speed of light in a vacuum is the same for all observers, regardless of their relative motion or of the motion of the source of the light." http://en.wikipedia.org/wiki/Theory_of_relativity Some people are simply not able to understand relativity and others might flatly refuse to accept it, because this new knowledge would turn their worldview upside down and force them to struggle with a huge reevaluation of physics. I think it would be polite of you, if you could at least admitt that you don't understand relativity and more importantly whether you are willing to try to learn and change your view or if you are rejecting relativity and prefer to continue holding a personal opinion. ---------- Assume a train that travels in the Speed of Light, and that the train has front-lights, also, assume there are two persons inside the train at its both ends facing each others, and the person who stands at the back of the train holds a light-bulk ... I have simple questions: 1. will the front-lights of the train lights leave its light-bulbs ? 2. will anyone be able to perceive the train front-lights ? 3. will the light of the light-bulk held by the person inside the train travels through the train to the other end ? 4. can the person in the other end of the train perceive the bulk-light ? 5. what happens to both light bulbs after a time, in that particular case ? I can't even imagine ... According to the theory of relativity nothing can travel through space relative the observer faster than light, anything with mass travels slower, and as such the train can not reach the speed of light relative someone else outside of the train. But in the "spirit" of the theory, I think the answers should be: 1) Yes, the light is leaving the train with c relative inside observers. 2) Yes, the light is leaving the train with c relative outside observers. 3) Yes, the light travels through the train with the speed of c. 4) Yes, and he measures the speed of light to be c relative him. 5) For the people in the train the light bulbs are not moving and nothing unusual happens. ---------- I really apologize Iggy. You behaved correctly all along. I didn't. Mea culpa. Ooh, and I almost forgot, I think it's an all to rare occurance that people admitt they where wrong, so I think this post is worthy a positive reputation point. Edited March 4, 2011 by Spyman Link to comment Share on other sites More sharing options...
owl Posted March 4, 2011 Share Posted March 4, 2011 Iggy, I answered every point in your previous post, one point at a time and asked you to specify exactly where you think I went wrong. You picked one: "If you are floating in space and you shoot a laser and 1 hour later it is 1210 million miles away then the laser light is receding from you at a velocity of 1210 million mph." Left guy didn't shoot a laser. You are changing the scene to fit your predisposition. It came from the center point in the scenario and went in the opposite direction at "C", 670 million mph (traveling, obviously 670 million miles.) Left guy went 540 million mph in the opposite direction (traveling, obviously 540 million miles.) The distance between his end point and the laser's end point at the end of the hour was 1210 million miles. Light did not go 1210 million mph. Right guy didn't fire the beam of light either. It went, as above, 670 million miles in the hour while right guy went 540 million miles. Light, at 130 million mph faster than right guy, went 130 million miles further. Will you please show me where you think I am wrong in the above recap? PS: I am really tired of hearing how wrong I am without specifics, point by point showing, as requested exactly where you think I got "derailed." Link to comment Share on other sites More sharing options...
Iggy Posted March 4, 2011 Share Posted March 4, 2011 Left guy didn't shoot a laser. I didn't specify who shot the laser because it doesn't matter. It [the laser] came from the center point in the scenario and went in the opposite direction at "C", 670 million mph (traveling, obviously 670 million miles.) Left guy went 540 million mph in the opposite direction (traveling, obviously 540 million miles.) The guy on the left did not travel 540 million miles away from himself. We are saying that light must recede at 670 million mph from any inertial observer which includes all three people in this thought experiment. That is what a constant speed of light means. The distance between his end point and the laser's end point at the end of the hour was 1210 million miles. Light did not go 1210 million mph. The speed of light, as figured by the guy on the left, is 1210 million miles per hour in this thought experiment. Right guy didn't fire the beam of light either. They can all three shoot a laser at the beginning, it doesn't matter. You have said that the speed of light is independent of the speed of the source, so the rays need to stay together. Will you please show me where you think I am wrong in the above recap? The guy on the left is no different from any guy that's floating in space. In this Newtonian thought experiment, he shoots a laser and one hour later the laser light is 1210 million miles away. This means that the laser receded from him at 1210 million mph. But, that is not how the world works. The speed of light is constant/invariant which means that any person who is moving at a constant velocity can look at a ray of light that is moving away from them and say "that light is moving 670 million miles every hour away from me". This thought experiment is different from the real world. The guy on the left cannot look at the ray of light and say "that light is moving 670 million miles every hour away from me". If distance and time are constant (meaning, everyone agrees on them) then the speed of light is not constant. Ooh, and I almost forgot, I think it's an all to rare occurance that people admitt they where wrong, so I think this post is worthy a positive reputation point. I agree on both points. Link to comment Share on other sites More sharing options...
owl Posted March 5, 2011 Share Posted March 5, 2011 I think I see reason for the discrepancy here. As I said in opening post 192, 3/3: "First, I am not debating SR, but rather arguing that local frames of reference do not describe the global reality of the situation." So we are really in two different "ballparks." If you are automatically dismissing my "global reality of the situation", then please just think of it as my counter thought experiment to the standard relativity stance that it all (the reality of the situation), always, depends on what different observers see from different frames of reference. Please re-read the post in reference above and reply to the "overview" of the situation as I presented it. Meanwhile, however redundantly, I'll reply to a few of your points. (All quotes, Iggy.) "I didn't specify who shot the laser because it doesn't matter." It matters from overview perspective that you specified its it origin at the central guy's position. "The guy on the left did not travel 540 million miles away from himself. We are saying that light must recede at 670 million mph from any inertial observer which includes all three people in this thought experiment. That is what a constant speed of light means." I didn't claim that he did. Impossible/absurd. He traveled 540 million miles away from center guy/position. From "global" or "overview" perspective (if you will bear with my "reality check" here) light always travels at "C", 670 million mph. That is what constant lightspeed means independent of who sees it from what frame of reference, if you can "think outside the frame" for just a moment here. "The speed of light, as figured by the guy on the left, is 1210 million miles per hour in this thought experiment." He is a confused stick figure guy in a confused thought experiment. In the overview (independent of the three FOR), and I am repeating, he actually went 540 to the left while light went 670 to the right of the central guy/point. The actual distance between the two end positions is 1210 million miles. Light did not travel 1210 million mph. "They can all three shoot a laser at the beginning, it doesn't matter. You have said that the speed of light is independent of the speed of the source, so the rays need to stay together." I have said, several times (see my rocket man shooting laser straight ahead of a speeding ship) that that beam will still travel at "C", not "C" plus the ship's velocity. You lost me on the last phrase. What does, "so the rays need to stay together" mean? Left guy firing a laser to the left and right guy firing one to the right will still create light beams going in opposite directions at 670 million mph, not, of course, their velocity plus 670 million mph. "he guy on the left is no different from any guy that's floating in space. In this Newtonian thought experiment, he shoots a laser and one hour later the laser light is 1210 million miles away. This means that the laser receded from him at 1210 million mph." I've addressed this twice or more already. His velocity in opposite direction does not add to the laser's speed, but the distance between end points is clearly 1210 million miles. "But, that is not how the world works. The speed of light is constant/invariant which means that any person who is moving at a constant velocity can look at a ray of light that is moving away from them and say "that light is moving 670 million miles every hour away from me"." That is how "frames of reference" differ from "how the world works." "The world"/cosmos does not depend on our measurements from all possible different frames of reference. This is what I call a reality check. Distances between objects in "the real world" do not "morph" all over the map just because the "mappers" are seeing/measuring from all different FORs. "This thought experiment is different from the real world. The guy on the left cannot look at the ray of light and say "that light is moving 670 million miles every hour away from me"." Your first sentence nails it! I'll not keep repeating my response to the latter. "If distance and time are constant (meaning, everyone agrees on them) then the speed of light is not constant." The speed of light is constant. Left and right guy each traveled 540 million miles in opposite directions from center, while light, originating at center (all as stated in *your thought experiment*) traveled 670 million miles to the right... all in the same hour. Trying to make all of the above sound like light traveled 1210 million miles in that hour in violation of "C" is simply a bogus argument. Link to comment Share on other sites More sharing options...
Iggy Posted March 6, 2011 Share Posted March 6, 2011 It doesn't look like you're going to get it, Owl. It matters from overview perspective that you specified [the laser's] origin at the central guy's position. The laser and all three people are in the same position at the beginning of the thought experiment. If all three people shoot a laser to the right at the beginning of the thought experiment then, according to your view, all three lasers must be at x = 670 million at the end of the thought experiment. This means that you have an inertial observer (the guy on the left) who shoots a laser and one hour later figures that the laser is 1210 million miles away. Whether you understand or agree or not, this means that he figures the speed of light to be 1210 million mph. In the real world, that doesn't happen. In the real world, the speed of light is the same whether you are drifting to the left or the right. Before a person can understand relativity they have to understand basic mechanics. You have to understand things like velocity and frames of reference. An internet forums is too difficult a setting to explain mechanics from scratch, besides which, you want to debate relativity and assert that you understand it which makes learning it all the more difficult. All told, I don't see any point in trying to communicate further. I realize that you don't see any problem with what you are saying. You don't see how your view conflicts with relativity. I think Dr. Rocket summed everything up nicely saying that the real problem is that you don't understand that you don't understand. I'm sure now that I won't be able to change that. Link to comment Share on other sites More sharing options...
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