- #1
Wes Tausend
Gold Member
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I gained most of my elementary understanding of Special Relativity (SR) from books by Isaac Asimov. I made the continuing mistake on this forum, of either taking some things he may have said too literally, or misconstruing them altogether, and they are not entirely correct. In other words, I believe Asimov, along with other popular science authors, may have repeatedly used loose "literary (artistic) license" to enhance explanation of some physical events that may not stand up under "technical definitions" during discussion on this forum. In the future, definitions given on this forum must take precedence.
I was invited to, quote, "ask questions about the explanation itself if you did not understand the explanation", which I interpret as the FAQ. Either way, I would like to clarify my understanding of this "technical definition" in SR and on this forum.
Postulates of Special Relativity
FAQ: Rest frame of a photon
Considering the Postulates of Special Relativity (above) that Einstein made, and the Physicsforums FAQ, Rest of a Photon, (above) the FAQ has apparently been constructed to be a nearly a word-for-word reference to the last sentence in the second postulate, and is firmly intended to be that way to serve the same purpose. The purpose is to establish a non-deviating foundation for SR. It is also this Physicsforums website's mission to discuss only established theories for clarity, all of which rely on some similar important foundation, and all welcome participants must try to strictly follow this mission and proper definitions.
1) It seems obvious to me that the above paragraph is essentially true, or is there a better way to say it?
Furthermore, when Einstein chose the wording of this SR postulate, he decided to base it on the basic supposition that all laws of physics always stayed the same for observers everywhere. In addition, he supposed earlier electromagnetic calculations by Maxwell hinted, and previous lightspeed measurements made by Michelson & Morley (M&M) indicated, light always traveled at an invariant speed in "free space" (a vacuum).
2) It seems obvious to me the above paragraph is also essentially true, or is there a better way to say it?
Concerning the importance of measurements, if some trustworthy individuals, including or other than M&M, later found any significant difference (other velocity) in "free space" lightspeed, Einstein knew that would immediately invalidate his SR postulate. So the words, "As measured", were carefully included in the SR postulate and are a necessary component. In other words, as were M&M, Einstein was aware most scientists were confounded by the invariance of lightspeed measured about eighteen years preceeding 1905 (1887), and as expected, M&M continued to make many re-measurements years after the 1905 SR Postulate, looking for a possible error. An error that has never been found to this day, and most likely never will be found... all because of the overwhelming success of this original SR Postulate.
3) It seems to me this last paragraph above is essentially true, or is there a better way to say it?
Thanks,
Wes
...
I gained most of my elementary understanding of Special Relativity (SR) from books by Isaac Asimov. I made the continuing mistake on this forum, of either taking some things he may have said too literally, or misconstruing them altogether, and they are not entirely correct. In other words, I believe Asimov, along with other popular science authors, may have repeatedly used loose "literary (artistic) license" to enhance explanation of some physical events that may not stand up under "technical definitions" during discussion on this forum. In the future, definitions given on this forum must take precedence.
I was invited to, quote, "ask questions about the explanation itself if you did not understand the explanation", which I interpret as the FAQ. Either way, I would like to clarify my understanding of this "technical definition" in SR and on this forum.
Postulates of Special Relativity
Einstein said:"1. First postulate (principle of relativity):
The laws by which the states of physical systems undergo change are not affected, whether these changes of state be referred to the one or the other of two systems of coordinates in uniform translatory motion. OR: The laws of physics are the same in all inertial frames of reference.
2. Second postulate (invariance of c):
As measured in any inertial frame of reference, light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body. OR: The speed of light in free space has the same value c in all inertial frames of reference.
FAQ: Rest frame of a photon
Physicsforums said:I've read that in relativity the concept of the rest frame of a photon doesn't make sense. Why is that?
A rest frame of some object is a reference frame in which the object's velocity is zero. One of the key axioms of special relativity is that light moves at c in all reference frames. The rest frame of a photon would require the photon to be at rest (velocity=0) and moving at c (velocity=299792458 m/s). That of course is contradictory. In other words, the concept doesn't make sense.
Considering the Postulates of Special Relativity (above) that Einstein made, and the Physicsforums FAQ, Rest of a Photon, (above) the FAQ has apparently been constructed to be a nearly a word-for-word reference to the last sentence in the second postulate, and is firmly intended to be that way to serve the same purpose. The purpose is to establish a non-deviating foundation for SR. It is also this Physicsforums website's mission to discuss only established theories for clarity, all of which rely on some similar important foundation, and all welcome participants must try to strictly follow this mission and proper definitions.
1) It seems obvious to me that the above paragraph is essentially true, or is there a better way to say it?
Furthermore, when Einstein chose the wording of this SR postulate, he decided to base it on the basic supposition that all laws of physics always stayed the same for observers everywhere. In addition, he supposed earlier electromagnetic calculations by Maxwell hinted, and previous lightspeed measurements made by Michelson & Morley (M&M) indicated, light always traveled at an invariant speed in "free space" (a vacuum).
2) It seems obvious to me the above paragraph is also essentially true, or is there a better way to say it?
Concerning the importance of measurements, if some trustworthy individuals, including or other than M&M, later found any significant difference (other velocity) in "free space" lightspeed, Einstein knew that would immediately invalidate his SR postulate. So the words, "As measured", were carefully included in the SR postulate and are a necessary component. In other words, as were M&M, Einstein was aware most scientists were confounded by the invariance of lightspeed measured about eighteen years preceeding 1905 (1887), and as expected, M&M continued to make many re-measurements years after the 1905 SR Postulate, looking for a possible error. An error that has never been found to this day, and most likely never will be found... all because of the overwhelming success of this original SR Postulate.
3) It seems to me this last paragraph above is essentially true, or is there a better way to say it?
Thanks,
Wes
...