EvanF Posted October 16, 2016 Posted October 16, 2016 (edited) Researchers have demonstrated one of Einstein's theories of relativity - that the further away from the Earths center of gravity you are, the faster time passes. Einstein was proven correct when two synchronized atomic clocks were placed on different floors of a tall building. After a year, the clock further from the Earth`s center of gravity gained time quicker. By moving about 10 feet to the top of the stairs, you would age sooner by just under a millionth of a second! Maybe it's just me, but I've never really followed the logic behind this experiment. (They also did another experiment like this but with the atomic clocks inside of planes that flew around the world.) It seems like theoretically the only way you could make "time" go faster is if you went into a dimension that has a different set of 'laws' than this reality, and then transitioned back to this dimension...As in you would spend 1 day in the other 'dimension' of time and space, then come back and it would be 10 years later in this reality. Edited October 16, 2016 by EvanF
imatfaal Posted October 16, 2016 Posted October 16, 2016 ! Moderator Note Please do not Hijack Speculations topics with your own questions about mainstream accepted physics - we keep the Speculations threads to allow Users to promote and defend their ideas and it is too much to ask them to defend received science at the same time. Too many branches also make the threads very hard to follow. Thanks https://en.wikipedia.org/wiki/Gravity_Probe_A https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment Just to give the usual example - our GPS satellites would not be of much use if we were not able to calculate the frequency offset with which to set the clocks on board. GPS is reliant on timing and the clocks on board are at a very different gravitational potential (meaning they run faster 45 microseconds a day) and are moving with high relative velocity compare to the earth's surface (meaning they run slower 7 microseconds per day); the net result , because the effect of the gravitational potential is higher in this case, is that the clocks on board the satellites run faster by 38 microseconds per day. This is enough that if we did not correct for this clock speed difference you would not be able to use a GPS system to find your house after a few minutes, your road after a couple of hours, and your town after a few days! You might want to check on the scientific / mathematical use of the word logic.
EvanF Posted October 16, 2016 Author Posted October 16, 2016 (edited) Well then...You've had quite a knee jerk reaction to me saying that haven't you. Edited October 16, 2016 by EvanF
swansont Posted October 16, 2016 Posted October 16, 2016 It seems like theoretically the only way you could make "time" go faster is if you went into a dimension that has a different set of 'laws' than this reality, and then transitioned back to this dimension...As in you would spend 1 day in the other 'dimension' of time and space, then come back and it would be 10 years later in this reality. Relativity describes some laws of nature in this reality. c is invariant, which has ramifications for time and length.
EvanF Posted October 16, 2016 Author Posted October 16, 2016 (edited) ! Moderator Note Please do not Hijack Speculations topics with your own questions about mainstream accepted physics - we keep the Speculations threads to allow Users to promote and defend their ideas and it is too much to ask them to defend received science at the same time. Too many branches also make the threads very hard to follow. Thanks https://en.wikipedia.org/wiki/Gravity_Probe_A https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment Just to give the usual example - our GPS satellites would not be of much use if we were not able to calculate the frequency offset with which to set the clocks on board. GPS is reliant on timing and the clocks on board are at a very different gravitational potential (meaning they run faster 45 microseconds a day) and are moving with high relative velocity compare to the earth's surface (meaning they run slower 7 microseconds per day); the net result , because the effect of the gravitational potential is higher in this case, is that the clocks on board the satellites run faster by 38 microseconds per day. This is enough that if we did not correct for this clock speed difference you would not be able to use a GPS system to find your house after a few minutes, your road after a couple of hours, and your town after a few days! You might want to check on the scientific / mathematical use of the word logic. Interesting... Do you have any thoughts of your own on this matter? Micro seconds huh... Logically, do you really think that would make any difference with GPS? It would only make a very tiny difference in GPS location. My opinion on Time Dilation is neither here nor there...I don't necessarily think it is literally 'mini time travel,' I think it's possibly just tiny mechanical/physical variation under certain gravitational forces. http://tycho.usno.navy.mil/ptti/1996papers/Vol%2028_16.pdf Taken from Henry F. Fliegel of The Aerospace Corporation in California: "The Operational Control System (OCS) of the Global Positioning System (GPS) does not include the rigorous transformations between coordinate systems that Einstein's general theory of relativity would seem to require...There is a very good reason for the omission: the effects of relativity where they are different from the effects predicted by classical mechanics and electromagnetic theory, are too small to matter-less than one centimeter for users on or near the Earth....in practice, neglect of relativity does not now contribute measurably to the GPS error budget, as the OCS software is currently configured." Edited October 16, 2016 by EvanF
swansont Posted October 16, 2016 Posted October 16, 2016 Interesting... Do you have any thoughts of your own on this matter? Micro seconds huh... Logically, do you really think that would make any difference with GPS? It would only make a very tiny difference in GPS location. My opinion on Time Dilation is neither here nor there...I don't necessarily think it is literally 'mini time travel,' I think it's possibly just tiny mechanical/physical variation under certain gravitational forces. http://tycho.usno.navy.mil/ptti/1996papers/Vol%2028_16.pdf Taken from Henry F. Fliegel of The Aerospace Corporation in California: "The Operational Control System (OCS) of the Global Positioning System (GPS) does not include the rigorous transformations between coordinate systems that Einstein's general theory of relativity would seem to require...There is a very good reason for the omission: the effects of relativity where they are different from the effects predicted by classical mechanics and electromagnetic theory, are too small to matter-less than one centimeter for users on or near the Earth....in practice, neglect of relativity does not now contribute measurably to the GPS error budget, as the OCS software is currently configured." Yes, absolutely. c is a big number. A nanosecond of timing error is a foot of positioning error. 3 microseconds is a kilometer of error. Length contraction is ignored, because it's a much smaller error than timing errors, or a few other positioning errors. Relying on logic based on a false premise (that relativity doesn't need to be incorporated in the analysis) isn't going to end well.
EvanF Posted October 16, 2016 Author Posted October 16, 2016 (edited) Yes, absolutely. c is a big number. A nanosecond of timing error is a foot of positioning error. 3 microseconds is a kilometer of error. Length contraction is ignored, because it's a much smaller error than timing errors, or a few other positioning errors. Relying on logic based on a false premise (that relativity doesn't need to be incorporated in the analysis) isn't going to end well. Perhaps your calculations based on relativity are inaccurate. Or maybe I interpreted Henry F. Fliegel's quote wrong, but I swear I thought he said, " the effects of relativity where they are different from the effects predicted by classical mechanics and electromagnetic theory, are too small to matter-less than one centimeter for users on or near the Earth....in practice, neglect of relativity does not now contribute measurably to the GPS error budget, as the OCS software is currently configured." I've heard this GPS relativity line regurgitated by people in mainstream "science" many times, (that 7 nanoseconds= a large amount of GPS measurement error.) But I don't know if that's accurate based on the data I just posted from The Aerospace Corporation. They tell us that satellites are around 20,000 miles from earth, and radio waves travel at the speed of light, so the information is getting to earth instantly anyways... Nanoseconds would of course be more significant if you had to send radio waves over the course of like a million miles from earth or something. Edited October 17, 2016 by EvanF
Strange Posted October 17, 2016 Posted October 17, 2016 I've heard this GPS relativity line regurgitated by people in mainstream "science" many times, (that 7 nanoseconds= a large amount of GPS measurement error.) But I don't know if that's accurate based on the data I just posted from The Aerospace Corporation. I am not a scientist (although I find your use of quotation marks around 'science' pretty offensive). I am an engineer who has worked on the design of GPS receivers and I can assure you that they do make relativistic corrections. I have only skimmed that paper, but a few immediate comments: 1. It is talking about the software on the satellites (and ground control stations) rather than receivers. 2. It is quite old and the accuracy of GPS has been improved since then. 3. You omitted the abstract of the paper, which describes its purpose: "We give and explain in detail the formulas for the relativistic corrections to be implemented in [various cases]" The cases where these corrections need to be applied now includes ground-based receivers. They tell us that satellites are around 20,000 miles from earth, and radio waves travel at the speed of light, so the information is getting to earth instantly anyways... About 100ms, not instantly. GPS is used, by many people, as a reference timing source that needs to be far more accurate than that.
swansont Posted October 17, 2016 Posted October 17, 2016 Perhaps your calculations based on relativity are inaccurate. Or maybe I interpreted Henry F. Fliegel's quote wrong, but I swear I thought he said, " the effects of relativity where they are different from the effects predicted by classical mechanics and electromagnetic theory, are too small to matter-less than one centimeter for users on or near the Earth....in practice, neglect of relativity does not now contribute measurably to the GPS error budget, as the OCS software is currently configured." The calculation is quite simple. d = ct 3 nanoseconds is a meter As I previously stated, as they are talking about "rigorous transformations between coordinate systems" (context matters), this is a matter of length contraction, which introduces a very small error. You might also have run across (p193, right before equation 10) Since GPS receivers work in the time and not in the frequency domain, they handle the velocity, gravity, and acceleration shifts differently than described above. First, each GPS space vehicle (SV) clock is offset from its nominal rate by about -4.45x10-10 (= -38 microseconds per day) to allow for the relativistic offsets between the differences between the SV and the ground. Of this -38 microseconds per day, about -45 are due to the gravitational potential difference between the SV at its mean distance and the earth's surface, and +7 to the mean SV speed, which is about 3.87 kmlsec. You can't just cherry-pick information to try and reinforced you preconceptions. That's not how it works. I've heard this GPS relativity line regurgitated by people in mainstream "science" many times, (that 7 nanoseconds= a large amount of GPS measurement error.) But I don't know if that's accurate based on the data I just posted from The Aerospace Corporation. They say the same thing, as I quoted above, and to say it's regurgitated (by people in "science") is more than a little bit insulting.
EvanF Posted October 17, 2016 Author Posted October 17, 2016 The calculation is quite simple. d = ct 3 nanoseconds is a meter As I previously stated, as they are talking about "rigorous transformations between coordinate systems" (context matters), this is a matter of length contraction, which introduces a very small error. You might also have run across (p193, right before equation 10) Since GPS receivers work in the time and not in the frequency domain, they handle the velocity, gravity, and acceleration shifts differently than described above. First, each GPS space vehicle (SV) clock is offset from its nominal rate by about -4.45x10-10 (= -38 microseconds per day) to allow for the relativistic offsets between the differences between the SV and the ground. Of this -38 microseconds per day, about -45 are due to the gravitational potential difference between the SV at its mean distance and the earth's surface, and +7 to the mean SV speed, which is about 3.87 kmlsec. You can't just cherry-pick information to try and reinforced you preconceptions. That's not how it works. They say the same thing, as I quoted above, and to say it's regurgitated (by people in "science") is more than a little bit insulting. I don't know why anyone would be insulted unless your identity itself is based on Relativity specifically... What I mean is that people in the science world will repeat this line that "GPS is dependent on Einstein's relativity," when GPS works fine with classical mechanics and electromagnetic theory. They of course need to be accurate and account for certain factors, but GPS works fine on Pre-Einstein classical relativity (Newtonian mechanics.) -2
imatfaal Posted October 17, 2016 Posted October 17, 2016 I don't know why anyone would be insulted unless your identity itself is based on Relativity specifically... What I mean is that people in the science world will repeat this line that "GPS is dependent on Einstein's relativity," when GPS works fine with classical mechanics and electromagnetic theory. They of course need to be accurate and account for certain factors, but GPS works fine on Pre-Einstein classical relativity (Newtonian mechanics.) In your post you quote a section of your own reference which clearly states that the clocks on GPS satellites require a 38 microsecond adjustment "to allow for the relativistic offsets" 38microseconds (a days cumulative error if relatvisitic corrections were not applied) is 11 km at the speed of light. You have quote-mined a paper that you clearly have not read
swansont Posted October 17, 2016 Posted October 17, 2016 I don't know why anyone would be insulted unless your identity itself is based on Relativity specifically... You implied mindlessly repeating a number, without understanding. What I mean is that people in the science world will repeat this line that "GPS is dependent on Einstein's relativity," when GPS works fine with classical mechanics and electromagnetic theory. Except that's not true. They of course need to be accurate and account for certain factors, but GPS works fine on Pre-Einstein classical relativity (Newtonian mechanics.) No, that's not what the article says. It says the coordinate system works fine without relativistic correction. The article quite clearly explains there is a relativistic timing correction. Why are you ignoring that?
Strange Posted October 17, 2016 Posted October 17, 2016 I don't know why anyone would be insulted unless your identity itself is based on Relativity specifically... It has nothing to do with relativity. You were (strongly) implying that scientists are being deliberately dishonest. What I mean is that people in the science world will repeat this line that "GPS is dependent on Einstein's relativity," when GPS works fine with classical mechanics and electromagnetic theory. I can assure you that is not true. The lead engineer on our design projects was one of the leading authorities on GPS systems. I don't think he included the relativistic corrections for fun.
swansont Posted October 17, 2016 Posted October 17, 2016 When the first satellite with an atomic clock was flown, there were still people unconvinced that the relativistic corrections were real. So they launched the first satellite without the clock corrections in place and confirmed the effect. http://relativity.livingreviews.org/open?pubNo=lrr-2003-1&page=articlese5.html (below figure 2. "There is an interesting story about this frequency offset...")
EvanF Posted October 17, 2016 Author Posted October 17, 2016 (edited) It has nothing to do with relativity. You were (strongly) implying that scientists are being deliberately dishonest. No. I simply said they were repeating something they heard from someone else. I never said they were deliberately lying. "Relativistic" includes Pre-Einstein classical mechanics. Einstein was not the first person to come up with "relativistic" math. But anyways...This OP quote from me about Time Dilation was never meant to be an absolute position on my part. My opinion on Time Dilation is neither here nor there, I simply have questions about it and need a better understanding of it. It seems that 'mini time travel' although somewhat insignificant, would still be quite a supernatural phenomenon that I simply question the reality of. (Not saying time travel is impossible.) Edited October 17, 2016 by EvanF
imatfaal Posted October 17, 2016 Posted October 17, 2016 ... "Relativistic" includes Pre-Einstein classical mechanics. Einstein was not the first person to come up with "relativistic" math. But anyways...This OP quote from me about Time Dilation was never meant to be an absolute position on my part. My opinion on Time Dilation is neither here nor there, I simply have questions about it and need a better understanding of it. It seems that 'mini time travel' although somewhat insignificant, would still be quite a supernatural phenomenon that I simply question the reality of. (Not saying time travel is impossible.) "Relativistic" would hardly ever refer to Galilean Relativity - it is generally used to differentiate between the realms of application of Newton Mechanics (Galilean Relativity) versus General Relativity / Special Relativity. In pre-Einstein mechanics there was absolute time and length - Einstein showed that Maxwell's work implied that it was light speed which was invariant and that time and length were variant. A clock frequency change due to relative velocity and/or change in gravitational potential are Relativistic corrections based on Einstein's theory and are only necessary when you have invariant c and equivalence principle.
EvanF Posted October 17, 2016 Author Posted October 17, 2016 (edited) "Relativistic" would hardly ever refer to Galilean Relativity - it is generally used to differentiate between the realms of application of Newton Mechanics (Galilean Relativity) versus General Relativity / Special Relativity. In pre-Einstein mechanics there was absolute time and length - Einstein showed that Maxwell's work implied that it was light speed which was invariant and that time and length were variant. A clock frequency change due to relative velocity and/or change in gravitational potential are Relativistic corrections based on Einstein's theory and are only necessary when you have invariant c and equivalence principle. The speed of light isn't necessarily constant though. https://www.sciencenews.org/article/speed-light-not-so-constant-after-all http://www.livescience.com/29111-speed-of-light-not-constant.html Edited October 17, 2016 by EvanF
imatfaal Posted October 17, 2016 Posted October 17, 2016 a. I didn't say it was - I said it was invariant, and it is. b. Those papers really do not support your argument.
Mordred Posted October 17, 2016 Posted October 17, 2016 (edited) a. I didn't say it was - I said it was invariant, and it is. b. Those papers really do not support your argument. Another common misunderstanding by those not familiar with relativity. I hate pop media articles grr. At least it included the arxiv article. It clearly shows the author isn't claiming relativity wrong. Just that the results may or may not have implications. However he did not correlate those implications outside of his experiment. The pop media coverage implies a conflict with relativity which isn't detailed in the arxiv paper. Edited October 17, 2016 by Mordred
EvanF Posted October 17, 2016 Author Posted October 17, 2016 (edited) a. I didn't say it was - I said it was invariant, and it is. b. Those papers really do not support your argument. a. By using "invariant" you were referring to Einstein's c, which of course stands for the constant speed of light in a vacuum. Einstein's Relativity relies on the constant speed of light. Since it's been proven recently that the speed of light is not always constant then math based on Einstein's relativity may not always be accurate. b. Even if that were true, that's fine with me because my original post was not intended to be an argument anyways. You created this thread, not me. Edited October 17, 2016 by EvanF
Strange Posted October 17, 2016 Posted October 17, 2016 Invariant means that all observers see the same same speed of light. This is what leads to length contraction and time dilation.
swansont Posted October 17, 2016 Posted October 17, 2016 a. "Invariant" means the same thing as constant. No, it doesn't. Something that is invariant is the same in different frames of reference. Constant is the same in a single frame. The invariant quantity is c, which is the speed of light in a vacuum. What happens to light when it's not in a vacuum is irrelevant to c being invariant.
Mordred Posted October 17, 2016 Posted October 17, 2016 a. By using "invariant" you were referring to Einstein's c, which of course stands for the constant speed of light in a vacuum. Einstein's Relativity relies on the constant speed of light. Since it's been proven recently that the speed of light is not always constant then math based on Einstein's relativity may not always be accurate. b. Even if that were true, that's fine with me because my original post was not intended to be an argument anyways. You created this thread, not me. The thread was created as you responded to another thread incorrectly with a false understanding.
EvanF Posted October 17, 2016 Author Posted October 17, 2016 No, it doesn't. Something that is invariant is the same in different frames of reference. Constant is the same in a single frame. The invariant quantity is c, which is the speed of light in a vacuum. What happens to light when it's not in a vacuum is irrelevant to c being invariant. When did you get the idea that I wasn't talking about the speed of light in a vacuum? In the so called "vacuum" of outer space there are particles (as well as who knows what else) that the so called constant speed of light collides with and changes the light speed.
Mordred Posted October 17, 2016 Posted October 17, 2016 (edited) yes we already account for the medium properties of space. This is done via redshift style calculations. More complexely the Sache-Wolfe integrated and non integrated. Scientists have always known c isn't constant in a medium and that space contains particles. This is the basis behind Baryon accoustic oscillations of the CMB. Edited October 17, 2016 by Mordred
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