Speed of Light: A universal Constant?
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From: Arthur Dent on 23 Jun 2005 22:09 bz wrote: > "Arthur Dent" <jp006t2227(a)blueyonder.co.uk> wrote in > news:1119567979.270217.176120(a)g49g2000cwa.googlegroups.com: > > > > > > > bz wrote: > >> "Arthur Dent" <jp006t2227(a)blueyonder.co.uk> wrote in > >> news:1119542237.498828.266500(a)g49g2000cwa.googlegroups.com: > >> > >> > bz wrote: > >> > > >> > I have read that Einstein was NOT familiar with MMX at the time he > >> > wrote his paper. I am not sure if this is true or not. He doesn't > >> > mention MMX in his 1905 papers. > >> > > > Consider my above statement as hearsay. Very well. I will also consider your assertions concerning light's speed to be hearsay also, or do you wish it to remain on the record? > .... > >> > unsuccessful attempts to discover any motion of the earth relatively to > >> > the ``light medium,'' > >> > > >> > suggest that the phenomena of electrodynamics as well as of mechanics > >> > possess no properties corresponding to the idea of absolute rest. > >> > http://www.fourmilab.ch/etexts/einstein/specrel/www > >> > > >> > (but Einstein never heard of MMX, performed 10 years earlier) > >> > > >> > What was he doing, too busy checking patents to read a scientific > >> > journal? > >> > > >> > >> You know, it doesn't really matter to me WHY Einstein didn't cite MMX in > >> his 1905 paper. He may have been familiar with MMX. He may have been > >> familiar with other papers that already cited MMX and thus had no need to > >> cite MMX. Those that say he was unfamiliar with MMX could be right, they > >> could be wrong. > >> > >> It doesn't matter. SR, GR and [thanks sue] EEP stand, or fall, on their > >> own. > >> > >> Show me some sub/super luminal photons. > > For someone that claims to be playing devil's advocate, and then saying > > it doesn't matter to you that your red herring has been proved wrong, > > you'd make a delightful back-seat driver of the type we've all come to > > cherish. Einstein DID cite MMX in his 1905 paper, as I have quoted. > > That is not what would call a proper citation. > He cites Maxwel, Newton, Lorentz, Hertz, Doppler, and M. Besso. > We may infer that he has read some of the papers of each of those authors and > is aware of some of the papers that THEY cite. > > It would be difficult to prove in a court of law [from the quote you > presented] that he is refering to the MMX experiment. He might be commenting > on another experiment or on something Maxwell or someone else wrote in their > paper. If you know of another experiment to attempt to discover any motion of the earth relatively to the ``light medium,'', I'm sure we'd all be interested to hear of it. > > As for showing you sub/superluminal photons, red-shift and blue-shift. > > > > Doppler's equation is f' = f.(c+ v.cos(phi))/c, > > nu'=nu*(1-cos(phi)*v/c)/sqrt(1-v^2/c^2) [SR] > Where phi is the angle of approach of the moving object. The minus sign doesn't show approach, which is blue shift, but no matter. > > > which Einstein accepts > > before he divides it by sqrt(1-v^2/c^2), > > For direct approach, phi=0 > so, the equation I wrote above can be rewritten: > nu'=nu*sqrt((1-v/c)/1+v/c)) Your sqrt(1-v^2/c^2) was derived from the earler equation ½[tau(0,0,0,t)+tau(0,0,0,t+x'/(c-v)+x'/(c+v))] = tau(x',0,0,t+x'/(c-v)) and that in turn was derived from Einstein's assertion without evidence that the time for light to go from (0,0,0) to (x',0,0) was the same as the time to go from (x',0,0) to (0,0,0), I do not accept his definition of time and I certainly do not accept that the times x'(c-v) and x'/(c+v) are equal. Therefore I do not accept that you can legitimately divide Doppler's equation. > > and since I do not accept > > his analysis of time, I see no reason to question Doppler. Therefore a > > red shifted photon is one that is subluminal. > > I will accept it as subluminal IF you can show, by timing its passage between > two points, that it is moving slower than c. Challenge accepted. Let there be two points in a vacuum, A and B. Let A and B be increasingly separated as a function of time. (That just means one is moving away from the other. We could perhaps use Earth and Mars as A and B) Let the speed of light be finite. (I think 300,000 km/sec has been quoted, and that is much less than infinity/sec, it takes around half an hour to get a signal to Mars and back) Let a ray of light be emitted from A toward B. Let it arrive at B when B is at a distance d from A. During the interval of time (finite and > 0)it takes for the light to return to A, the distance between A and B will be greater than d. Call this distance d' > d. By Einstein's definition that it takes the same time to make the return trip from B to A as it took to travel from A to B, and the distance between A and B now being greater when the light returns, it follows that there are two speeds of light, c' = d'/t and c = d/t, by the standard definition of speed. If you have some other definition of speed, keep it to yourself, please. Which you call subliminal and which you call superliminal is up to you, but one speed is greater than the other, by Einstein's own definition. A non-relativist would simply say it takes longer because it has further to go, but he'd also employ the vector addition of velocities, (c +/- v)t for the distances, and not the composition of velocities. > > > You've been shown. Denial is the argument of a relativist. > > Show me photons that MOVE slower than light [in vacuum] and you will have my > applause. Thank you. Read the above. You may now clap. > > [einstine says] [snip] Who cares what the lunatic said? He was totally off his rocker when he said it takes the same time for light to travel from A to B as it takes from B to A, his entire argument was built on that and was subjective and irrational. Also, I've heard he claimed the speed of light is the same in all frames of reference, but that was hearsay. Oft repeated hearsay, but hearsay nevertheless. What he did say was c = 2AB/(t'A - tA), taking the mean speed out and back. If you went up a hill from A to B for one mile at 30 mph, turned around and came back to A, how fast would you have to go to get a mean speed of 60 mph? Arthur Dent.
From: Arthur Dent on 23 Jun 2005 22:31 bz wrote: > "Arthur Dent" <jp006t2227(a)blueyonder.co.uk> wrote in > news:1119455576.127223.290020(a)g43g2000cwa.googlegroups.com: > > > bz wrote: > > > > "If you can follow my 'slinky' waves, you may change your mind." > > > > Not a hailstone's chance in the core of the sun. > > > > I simply move your slinky toward or away from me at v > > I said transverse waves. Side to side. > > However, if you look closely at waves along the axis, you will see that > they, also, will NOT follow c'=c+v [unless you compress all the space out > from in between the turns. Of course they do. You are carrying the slinky, making waves. The waves have some velocity c relative to you. I drive toward you in my car, you have some v relative to me, and the slinky wave you carry has a velocity c+v relative to me. That's straightforward Galilean vector addition of velocities. If you want to wave the slinky while driving, toward me, that's ok too. Relative to me the slinky wave is c+v. > > >, or walk toward > > it or away from it, > > and the speed of the slinky wave is c+v in my frame of reference if it > > is c in the slinky's frame > > of reference. Perhaps you do not understand the meaning of relative > > motion, > > Perhaps I don't understand what YOU mean by relative motion. Hmmm... Let's try this. You are spacewalking outside the International Space Station, on a safety tether. The ISS is going around the Earth taking 1.5 hours to complete a full orbit, passing over some fixed point below repeatedly. We say it is travelling at 17,000 mph, because in one hour it will be 17,000 miles further away. You have almost zero relative motion to the ISS, and you too are travelling at 17,000 mph. So is your speed 17,000 mph, or is it 0 mph? Jeez, I shouldn't have to be doing this kiddy stuff. > > > but I do not see a way > > to pardon it or discuss such simple concepts further with you. > > That is a pity. > > I have never found someone who didn't know something I didn't know. > I could always learn something from anyone. You refuse to learn from Henri, prefering to jibe, and he knows a hell of a lot. > I have also never met anyone that knew so much that they couldn't learn > something worthwhile from me. > You appear to be an exception to the rule. If you have something to teach I'll listen. I just dont see the point of arguing for the sake of it. Arthur. > So long and thanks for the fish. > > > > -- > bz > > please pardon my infinite ignorance, the set-of-things-I-do-not-know is an > infinite set. > > bz+sp(a)ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap
From: Jerry on 23 Jun 2005 22:59 Henri Wilson wrote: > On Thu, 23 Jun 2005 15:47:56 +0000 (UTC), bz <bz+sp(a)ch100-5.chem.lsu.edu> > wrote: > >download some data and look at your 'stable'. > >http://www.aavso.org/data/download/ > > not very illuminating... You have to remember that the data includes contributions from many observers who have differing "observer bias." If you unselectively overlay variant observer estimates, your light curves become undecipherable. The trick is to first sort by observer, eliminate observations by sporadic contributors (who only introduce noise, in my opinion), and do curve fits on the contributions from individual observers where they have become "enthusiastic" and have made a dense set of observations over several cycles. Once you have your individual observer fits, then you can start combining curves. Jerry
From: Jerry on 24 Jun 2005 05:05 Jerry wrote: > Henri Wilson wrote: > > On Thu, 23 Jun 2005 15:47:56 +0000 (UTC), bz <bz+sp(a)ch100-5.chem.lsu.edu> > > wrote: > > > >download some data and look at your 'stable'. > > >http://www.aavso.org/data/download/ > > > > not very illuminating... > > You have to remember that the data includes contributions from > many observers who have differing "observer bias." If you > unselectively overlay variant observer estimates, your light > curves become undecipherable. The trick is to first sort by > observer, eliminate observations by sporadic contributors (who > only introduce noise, in my opinion), and do curve fits on the > contributions from individual observers where they have become > "enthusiastic" and have made a dense set of observations over > several cycles. Once you have your individual observer fits, > then you can start combining curves. Warning: unselectively combining curves introduces the danger of smoothing out real variation!!! If you force-fit a Wilson or Androcles aT curve to the data, you deserve to be called an idiot. Jerry
From: Jerry on 24 Jun 2005 05:21
Jerry wrote: > Warning: unselectively combining curves introduces the danger > of smoothing out real variation!!! If you force-fit a Wilson > or Androcles aT curve to the data, you deserve to be called an > idiot. Typo: "BaT" curve, not "aT" curve. Jerry |