Known physics defeated by simple puzzle?
in [Relativity]
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From: Peter Webb on 1 Apr 2010 21:02 "Ste" <ste_rose0(a)hotmail.com> wrote in message news:7d0579a0-673d-4f62-9cf4-6b193018d5d9(a)q23g2000yqd.googlegroups.com... > On 2 Apr, 00:47, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > wrote: >> "Ste" <ste_ro...(a)hotmail.com> wrote in message >> >> > Moreover, there is a question as to *what* is being accepted: even I >> > accept that the maths of SR seems to quantify our observations, and >> > indeed I expect almost all physicists will accept that. But the >> > question here is not between SR and nought. It is about how to >> > interpret the mechanisms behind the observations described by SR. >> >> Ohh, you want an "interpretation". That is completyely different to >> asking >> if it is "real" or "apparent". > > I was using the word "interpret" to mean "gain meaningful > understanding of", not "offer a subjective and highly-contentious > account of", which I think is how you interpreted the word, as it > were. > If you want to gain a "meaningful understanding of SR", you should study it. If you want an "interpretation", focus on studying Minkowski space time. > > >> > And just to move to an easier analogy, I don't care how much you can >> > accurately quantify something like acoustic Doppler shifting with an >> > equation, my question would be this: is the Doppler shift a product of >> > the change of interaction between source and receiver, or is the >> > source "really" changing frequency by some unknown mechanism? The >> > answer, of course, is that the Doppler effect is apparent - there is >> > nothing inherent about the source that needs to change in order to >> > explain the phenomenon. >> >> The Doppler shift is real. Frequencies really do change. > > Yes, but it involves no change in the frequency generated by the > source. > The frequency of the sound depends entirely on the reference frame in which it is measured. Changing the relative speed of the train definitely changes the frequency of the sound. You can easily verify this yourself. > > >> > My question with SR remains the same: is it >> > "real", or is it an apparent effect. >> >> Like the Doppler shift, it is both real and apparent. >> >> As I said already. > > It is not "real" in the sense that it involves a change in the > attributes of the source - it is "apparent" in the sense it involves a > change in the relationship between the source and receiver. That is not what "apparent" vs "real" means, at least in common usage. The frequency of a sound generated by a moving train definitely does really change as its speed changes. Measure it for yourself if you don't believe it. Of course, the frequency that you measure is a function of the reference frame in which you measure it. In this respect, the "frequency" of a sound is not a precisely defined concept. The normal use is that the frequency is tacitly assumed to be that which is measured at rest. Same as length in SR. When you want to compare frequencies in two different reference frames, this definition breaks down as there are two different possible base frames for measurement, and you have to be specific about which reference frame you are measuring frequency in. Same, again, as for length in SR. HTH
From: Sue... on 1 Apr 2010 21:09 On Apr 1, 8:25 pm, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > "Sue..." <suzysewns...(a)yahoo.com.au> wrote in message > > news:5b7b99cd-6a9e-4db1-9589-03a48bf3ff55(a)33g2000yqj.googlegroups.com... > On Apr 1, 7:47 pm, "Peter Webb" > <webbfam...(a)DIESPAMDIEoptusnet.com.au> > > ======================== > > > Nobody takes me or Einstein "at his word". I believe SR because it matches > > experiment. > > Could you please name two or three experiments > that you find most supportive of Einstein's > Special Relativity? > ========================== > > There are hundreds. I do not find any one of them "more supportive" than any > of the others; all experimental tests of SR support it completely. "In religion and politics people's beliefs and convictions are in almost every case gotten at second-hand, and without examination, from authorities who have not themselves examined the questions at issue but have taken them at second-hand from other non-examiners, whose opinions about them were not worth a brass farthing." --Mark Twain > > It would be like asking a physicist in the 19th century which experiments > they find most supportive of Newton's theory of gravity. The fact that > apples fall to the ground? That planets follow elliptical orbits? That > spiral galaxies exist and are stable? The periods of double stars? Synthetic > experiments measuring gravitational attraction in a laboratory? *All* of > these completely support Newton's theory (at least to the limits of 19th > Century understanding and measurement). > > You can't get "more supportive" than "completely supports". All of the above > experiments "completely support" Newton's theory of gravity. Similarly,http://www.phys.ncku.edu.tw/mirrors/physicsfaq/Relativity/SR/experime... > lists about 500 experiments which "completely support" SR. > > Perhaps if you were to supply some objective measure of how one experiment > which completely supports a theory offers more support than some other > experiment which also completely supports the theory, I would be in a > position to rank them. I asked your favourite (most convincing) SR experiment. If you don't know of any maybe you will tell us your favourite food or favourite color. GawdKnows we won't ask what time it is because we have plenty of diagrams of clock mechanisms. :-)) > > Perhaps as an example you could say which experiment best supports Newton's > theory of gravity, and say why this is the "best"? With that definition in > hand of "best", and a worked example of why it is the "best", I could offer > in the same spirit a few experiments that do the same for SR? I find Lord Cavendish's determination within 5 percent quite convincing taken alongside orbital data of the time. Sue...
From: spudnik on 1 Apr 2010 21:18 Doppler-shifting of sound is an everyday occurance, but how much of the redshifting that is seen in the sky, is a whole another matter, whether it is due to velocity, or to the medium of space (unless, like certain aetherists, you believe in an absolute vacuum, and so did Pascal, when he measured it .-) as for "Newton's algebraic version of Kepler's orbital constraints, that he manifestly stole from Hooke," isn't the problem of spiral galaxies where the whole urstuff of darkmatter darkenergy quintesscence is gotten? Lightcones are dead; long-live Minkowski! > If you want to gain a "meaningful understanding of SR", you should study it. > If you want an "interpretation", focus on studying Minkowski space time. > The frequency of a sound generated by a moving train definitely does really > change as its speed changes. Measure it for yourself if you don't believe > it. > > Of course, the frequency that you measure is a function of the reference > frame in which you measure it. In this respect, the "frequency" of a sound > is not a precisely defined concept. The normal use is that the frequency is > tacitly assumed to be that which is measured at rest. Same as length in SR. > When you want to compare frequencies in two different reference frames, this > definition breaks down as there are two different possible base frames for > measurement, and you have to be specific about which reference frame you are > measuring frequency in. Same, again, as for length in SR. thus: yeah; the funny thing was, the Earth of Gauss and of Aristarchus was a part of some cosmography. (you, however, may be in your own me-verse; so, how does Shroedinger's cat smell, these days , thereat ?-) > Groan. --Light: A History! http://21stcenturysciencetech.com --NASCAR rules on rotary engines! http://white-smoke.wetpaint.com
From: Peter Webb on 1 Apr 2010 21:56 "Sue..." <suzysewnshow(a)yahoo.com.au> wrote in message news:bc267474-80ea-41e5-86f5-3a1b3878a4cd(a)8g2000yqz.googlegroups.com... On Apr 1, 8:25 pm, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > "Sue..." <suzysewns...(a)yahoo.com.au> wrote in message > > news:5b7b99cd-6a9e-4db1-9589-03a48bf3ff55(a)33g2000yqj.googlegroups.com... > On Apr 1, 7:47 pm, "Peter Webb" > <webbfam...(a)DIESPAMDIEoptusnet.com.au> > > ======================== > > > Nobody takes me or Einstein "at his word". I believe SR because it > > matches > > experiment. > > Could you please name two or three experiments > that you find most supportive of Einstein's > Special Relativity? > ========================== > > There are hundreds. I do not find any one of them "more supportive" than > any > of the others; all experimental tests of SR support it completely. "In religion and politics people's beliefs and convictions are in almost every case gotten at second-hand, and without examination, from authorities who have not themselves examined the questions at issue but have taken them at second-hand from other non-examiners, whose opinions about them were not worth a brass farthing." --Mark Twain ____________________________________ Huh? We are talking about SR, which is a branch of physics, and is not part of religion or politics. > > It would be like asking a physicist in the 19th century which experiments > they find most supportive of Newton's theory of gravity. The fact that > apples fall to the ground? That planets follow elliptical orbits? That > spiral galaxies exist and are stable? The periods of double stars? > Synthetic > experiments measuring gravitational attraction in a laboratory? *All* of > these completely support Newton's theory (at least to the limits of 19th > Century understanding and measurement). > > You can't get "more supportive" than "completely supports". All of the > above > experiments "completely support" Newton's theory of gravity. > Similarly,http://www.phys.ncku.edu.tw/mirrors/physicsfaq/Relativity/SR/experime... > lists about 500 experiments which "completely support" SR. > > Perhaps if you were to supply some objective measure of how one experiment > which completely supports a theory offers more support than some other > experiment which also completely supports the theory, I would be in a > position to rank them. I asked your favourite (most convincing) SR experiment. _______________________________________ No you didn't. You asked for the most supportive. If you don't know of any maybe you will tell us your favourite food or favourite color. GawdKnows we won't ask what time it is because we have plenty of diagrams of clock mechanisms. :-)) _____________________________________ I don't really have a fixed favourite food or a favourite color. It depends on what I feel like at the time. I like both cornflakes and oysters, but at different times of the day. My favourite color in M&Ms is red; my favourite colur for the sky is blue. > > Perhaps as an example you could say which experiment best supports > Newton's > theory of gravity, and say why this is the "best"? With that definition in > hand of "best", and a worked example of why it is the "best", I could > offer > in the same spirit a few experiments that do the same for SR? I find Lord Cavendish's determination within 5 percent quite convincing taken alongside orbital data of the time. _________________________________ I find lots of arguments for both Newton's gravity and SR very convincing. You don't state why you think the Cavendish experiment is more convincing than any of the others (or even that you do find it more convincing than any of the others). Unless you can supply some measure which makes some experiment more convincing than others, I cannot tell you which of the experimental tests of Newton's gravity or SI I find the "most convincing". Any more than I can tell you what my "favourite" food is. There is no one favourite food which I prefer to all others at all times, there are many foods I like. There is no one experimental verification of Newton's gravity which I prefer to all others at all times; it depends upon what aspects of Newton's gravity I want to verify. If you want to define "favourite" as meaning simplest and of most historical significance, I would probably pick (for Newton's gravity and SR respectively); 1. The fact that apples fall to the ground when released. 2. The null result of the MM experiment. If you want to define "favourite" as meaning the most comprehensive and easily verified, again for Newton and SR respectively it would probably be: 1. We have launched thousands of spacecraft which were designed using Newton's law of gravity and they demonstrably all work. 2. Every day we accelerate particles close to light using machines designed using SR, and they demonstrably all work. Other definitions of "favourite" would produce different answers. What definition of favourite did you have in mind, exactly?
From: Sue... on 1 Apr 2010 22:59
On Apr 1, 9:56 pm, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > "Sue..." <suzysewns...(a)yahoo.com.au> wrote in message > > news:bc267474-80ea-41e5-86f5-3a1b3878a4cd(a)8g2000yqz.googlegroups.com... > On Apr 1, 8:25 pm, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > wrote: > > > "Sue..." <suzysewns...(a)yahoo.com.au> wrote in message > > >news:5b7b99cd-6a9e-4db1-9589-03a48bf3ff55(a)33g2000yqj.googlegroups.com... > > On Apr 1, 7:47 pm, "Peter Webb" > > <webbfam...(a)DIESPAMDIEoptusnet.com.au> > > > ======================== > > > > Nobody takes me or Einstein "at his word". I believe SR because it > > > matches > > > experiment. > > > Could you please name two or three experiments > > that you find most supportive of Einstein's > > Special Relativity? > [...] ================================ > 2. The null result of the MM experiment. That supports the constancy of light speed predicted by Maxwell. It is consistent with a dielectric that moves along with our planet (atmosphere) and shows nothing about inertial effects of relativity because moving masses were not measured. The experiment was performed in 1887 so it was not designed to test a theory of the 1900s but that certainly does not disqualify it as long as the data is relevant. Did you have doubts that the atmosphere moves with our planet before you read about special relativity? Sue... http://en.wikipedia.org/wiki/Impedance_of_free_space |