From: Peter Webb on 1 Apr 2010 23:05 "Sue..." <suzysewnshow(a)yahoo.com.au> wrote in message news:4fa0f29d-c618-4068-a1cb-844017e411ef(a)k17g2000yqb.googlegroups.com... 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. ______________________________ Yes. Did you have doubts that the atmosphere moves with our planet before you read about special relativity? _____________________________ No. Hope this helps.
From: Sue... on 1 Apr 2010 23:42 On Apr 1, 11:05 pm, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > "Sue..." <suzysewns...(a)yahoo.com.au> wrote in message > > news:4fa0f29d-c618-4068-a1cb-844017e411ef(a)k17g2000yqb.googlegroups.com... > 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. ================ > > ______________________________ > Yes. > > Did you have doubts that the atmosphere > moves with our planet before you read > about special relativity? > > _____________________________ > No. > > Hope this helps. A.Einstein ~1920: <<On this point we are enlightened by a most important experiment which the brilliant physicist Fizeau performed more than half a century ago, and which has been repeated since then by some of the best experimental physicists, so that there can be no doubt about its result. The experiment is concerned with the following question. Light travels in a motionless liquid with a particular velocity w. How quickly does it travel in the direction of the arrow in the tube T (see the accompanying diagram, Fig. 3) when the liquid above mentioned is flowing through the tube with a velocity v? FIG. 3. In accordance with the principle of relativity we shall certainly have to take for granted that the propagation of light always takes place with the same velocity w with respect to the liquid, whether the latter is in motion with reference to other bodies or not. >> http://www.bartleby.com/173/13.html So it seems your favourite ~tests~ of Special Relativity actually predate Einstein's writing on the subject. Again, there is nothing wrong with that where hind-sight can be blind. These seem convincing of one of the postulates of Special Relativity: http://en.wikipedia.org/wiki/Michelson_and_morley http://en.wikipedia.org/wiki/Fizeau_experiment http://en.wikipedia.org/wiki/De_Sitter_double_star_experiment http://en.wikipedia.org/wiki/Impedance_of_free_space So why do we need contracting matter and crazy clocks to say: << Einstein's relativity principle states that: All inertial frames are totally equivalent for the performance of all physical experiments. In other words, it is impossible to perform a physical experiment which differentiates in any fundamental sense between different inertial frames. By definition, Newton's laws of motion take the same form in all inertial frames. Einstein generalized[1] this result in his special theory of relativity by asserting that all laws of physics take the same form in all inertial frames. >> http://farside.ph.utexas.edu/teaching/em/lectures/node108.html [1]<< the four-dimensional space-time continuum of the theory of relativity, in its most essential formal properties, shows a pronounced relationship to the three-dimensional continuum of Euclidean geometrical space. In order to give due prominence to this relationship, however, we must replace the usual time co-ordinate t by an imaginary magnitude sqrt(-1) ct proportional to it. Under these conditions, the natural laws satisfying the demands of the (special) theory of relativity assume mathematical forms, in which the time co-ordinate plays exactly the same rôle as the three space co-ordinates. >> http://www.bartleby.com/173/17.html << where epsilon_0 and mu_0 are physical constants which can be evaluated by performing two simple experiments which involve measuring the force of attraction between two fixed charges and two fixed parallel current carrying wires. According to the relativity principle, these experiments must yield the same values for epsilon_0 and mu_0 in all inertial frames. Thus, the speed of light must be the same in all inertial frames. >> http://farside.ph.utexas.edu/teaching/em/lectures/node108.html Sue...
From: Sam Wormley on 1 Apr 2010 23:54 On 4/1/10 7:01 PM, Sue... wrote: > Could you please name two or three experiments > that you find most supportive of Einstein's > Special Relativity? > > I may have overlooked some of the better > examples. > > Sue... > Physics FAQ: What is the experimental basis of special relativity? http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html
From: Sam Wormley on 1 Apr 2010 23:56 On 4/1/10 8:09 PM, Sue... wrote: > I asked your favourite (most convincing) SR experiment... Physics FAQ: What is the experimental basis of special relativity? http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html
From: Peter Webb on 2 Apr 2010 01:02
"Sue..." <suzysewnshow(a)yahoo.com.au> wrote in message news:d2af3463-b106-4583-a3ac-01c43bf4b4a6(a)o30g2000yqb.googlegroups.com... On Apr 1, 11:05 pm, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > "Sue..." <suzysewns...(a)yahoo.com.au> wrote in message > > news:4fa0f29d-c618-4068-a1cb-844017e411ef(a)k17g2000yqb.googlegroups.com... > 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. ================ > > ______________________________ > Yes. > > Did you have doubts that the atmosphere > moves with our planet before you read > about special relativity? > > _____________________________ > No. > > Hope this helps. A.Einstein ~1920: <<On this point we are enlightened by a most important experiment which the brilliant physicist Fizeau performed more than half a century ago, and which has been repeated since then by some of the best experimental physicists, so that there can be no doubt about its result. The experiment is concerned with the following question. Light travels in a motionless liquid with a particular velocity w. How quickly does it travel in the direction of the arrow in the tube T (see the accompanying diagram, Fig. 3) when the liquid above mentioned is flowing through the tube with a velocity v? FIG. 3. In accordance with the principle of relativity we shall certainly have to take for granted that the propagation of light always takes place with the same velocity w with respect to the liquid, whether the latter is in motion with reference to other bodies or not. >> http://www.bartleby.com/173/13.html So it seems your favourite ~tests~ of Special Relativity actually predate Einstein's writing on the subject. ______________________________________ Sure. And the observation that apples fall to the ground predates Newton's law of gravity. I note the rest of your post asks why Einstein said some particular thing. While I feel I know SR and the Universal Law of Gravity quite well, I don't the history behind the theories well, much less the motivation behind why the people who contributed to their development said the many various things they did through the course of their lives. I am a physicist, not a historian or psychologist. You can quote all the bits of Newton or Einstein writings you like, and ask me why they said those things, and the answer will be the same - I don't know. I simply don't know the history behind these, any more than I know the history behind the solution of a quadratic equation, or why the person who first solved the quadratic did so. These are questions of history and psychology, not questions about science or maths. Of course, if you have any questions concerning the scientific aspects of SR or the Universal Law of Gravity, feel free to ask. But for historical information about SR and Newton's law of gravity, I'm not the person to ask. |