Speed of Light: A universal Constant?
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From: bz on 24 Jun 2005 05:37 "Arthur Dent" <jp006t2227(a)blueyonder.co.uk> wrote in news:1119578949.505498.21960(a)o13g2000cwo.googlegroups.com: > 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, > The pulses must start from A and from B at the same time so that they travel the same distance. -- 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: bz on 24 Jun 2005 05:42 "Jerry" <Cephalobus_alienus(a)comcast.net> wrote in news:1119581963.931090.287500(a)g47g2000cwa.googlegroups.com: > 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. > Can you recommend a good program for fitting the data? -- 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 24 Jun 2005 07:04 bz wrote: > "Jerry" <Cephalobus_alienus(a)comcast.net> wrote in > news:1119581963.931090.287500(a)g47g2000cwa.googlegroups.com: > > > 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. > > > > Can you recommend a good program for fitting the data? Since my brother ("Minor Crank") is a former AAVSO member and I was the baby sister (26 year age difference!) that he regularly took out on star parties, yes, I do know of and have used several curve fit programs. However, each involves assumptions. For example, for fitting eclipsing binary data, there is Phoebe, that runs on my brother's Linux box, that starts with the photometric data and takes into account limb darkening, tidal distortions in stellar shapes for close binaries, etc. I've also used the original Wilson-Devinney code, but you have to be a real geek. To fit data for non-binary systems and to fit poorly sampled light curves like typical AAVSO data, you have to fit a template to the data. I've used some code by Andrew Layden for this, and plotted with Super-Mongo. Again, you need a Linux box. Layden's code works even better if you have closely sampled photometric data, and was what I used when I responded to Arthur about RT Aur a few posts back. http://groups-beta.google.com/group/sci.physics/msg/eafbdb94c0eacfa1 Hope this helps. Jerry
From: bz on 24 Jun 2005 07:29 "Arthur Dent" <jp006t2227(a)blueyonder.co.uk> wrote in news:1119578949.505498.21960(a)o13g2000cwo.googlegroups.com: > > 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? Depends on which statement you might be thinking of. I will remain 'on record' ..... >> >> 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 >> comment > ing >> on another experiment or on something Maxwell or someone else wrote in >> th > eir >> 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. [quote] What was the experimental support for this claim? There were several experiments concerning the electrodynamics of moving bodies, which are not very well known today, but Einstein knew these experiments: W.C. Roentgen, Annalen der Physik 35 (1888), pg 264. Note that Roentgen describes in this paper an "unsuccessful" experiment, where he tried to measure the velocity of the Earth through the ether (a "primitive" version of the Trouton-Noble experiment). A.Eichenwald, Annalen der Physik 11 (1903), pg 1 and. pg 241. Experiments concerning the so called Roentgen convection, with an electric field (See Sommerfeld Vol. 3, Chapter 4). H. A. Wilson, Philosph. Transact. Roy. soc. London 204 (1904), pg 121. H. A. Wilson, M. Wilson, Philosph. Transact. Roy. soc. London 89 (1913), pg 99. Experiments concerning the so called Roentgen convection, with a magnetic field (See Sommerfeld Vol. 3, Chapter 4). Rayleigh Phil. Mag. (6) 4, pg 678 (1902). Brace Phil. Mag. (6) 7, pg 317 (1904). Experiments concerning the effect of the motion of the Earth on double refraction. Arago Examined the expected change in focus of a refracting telescope due to earth's motion around the sun. This is first order in v/c if one assumes light is fully dragged by the lens. The null result is consistent with SR Fizeau Measured the speed of light in moving materials. The Fresnel drag coefficient is solidly established by experiments, and is consistent with SR to within experimental resolutions. Hoek Much more accurate version of the basic concept of Arago's experiment, using a terrestrial source and a square (ring) interferometer with one side in water and three in air. The null result is consistent with Arago's result and with Fresnel's drag coefficient, and with SR. Bradley Bradley (1727) discovered that the images of stars move in small ellipses. This is explained as aberration due to the earth's motion around the sun. This is inconsistent with a simple model of light as waves in an aether which is dragged along by the earth; it is consistent with SR. Airy Airy (1871) tested whether stellar aberration remained unchanged if the telescope was filled with water. It did. [unquote] Note: MMX is not mentioned in the above list. taken from... http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html [quote] as of this writing there are no reproducible and generally-accepted experiments that are inconsistent with SR, within its domain of applicability. [unquote] The author has reviewed many experiments. >> > 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. Velocity is a vector, with direction. The equation is correct with phi representing 'the angle of approach' of the moving object. >> > 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 > ý[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. You are not very accepting, are you? >> > 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 >> bet > ween >> 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 FALSE!. The light must start from B on its trip to A at the same time it starts from A on its trip to B. > 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. You have two different distances, two different time intervals. If you measure the different distances and the different time intervals, you will find that distance1/time1 = distance2/time2 so c1 = c2 = c. > Which you call subliminal and which you call superliminal is up to you, neither will be other than c. > but one speed is greater than the other, by Einstein's own definition. No. You must take the distance traveled in each case divided by the time for that case. > 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. distance over time. >> > 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. I applaud your 'good try' but no banana. Contemplate the sound of one hand clapping. >> [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? Travel one direction at 60 mph, how fast do you need to travel the other direction in order to average 60 mph? -- 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: bz on 24 Jun 2005 07:58
"Arthur Dent" <jp006t2227(a)blueyonder.co.uk> wrote in news:1119580301.499846.166140(a)f14g2000cwb.googlegroups.com: > > > 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. No. The ends of the slinky are fixed in place. We can send waves along the slinky, we do not MOVE the slinky's ends. > 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. Nope. The slinky is fixed in place. Your motion wrt the slinky brings the wave crests to you sooner because there is less distance for them to travel. BTW, your vehicle is limited in speed. It must not go as fast or faster than the waves go on the slinky. As they go by your two detectors, you find that the time for a crest to pass between the two detectors is identical, no matter what speed your car is moving (within the limits mentioned above). > 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. Not if the slinky behaves like light. >> >, 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. Then what ever happens, as long as the tether is not taunt, I am moving at a rather low velocity wrt the ISS. If it were taunt, I could be rotating around the station at a high velocity, until I got all wrapped up in what I was doing. > 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? 17000 mph wrt 'some fixed point on earth' 0 mph wrt the ISS. The radius of a 1.5 hr orbit around earth is 6.314e3 km or 3861 mi. V.orb for such an orbit is 7.231 km/s or 16,174.36 mph > Jeez, I shouldn't have to be doing this kiddy stuff. You asserted that I didn't understand relative motion. >> > 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. Oh, I am learning from Henri. I am helping him test his program and model. I think he is wrong, and that his program should ALSO show what the results would be in an Einstein universe. Until he can show his results are BETTER than Einstein's, he will only have half a theory. That means that he must understand Einstein's theorys BETTER than his critics. He hasn't reached that point yet. >> 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. Neither do I. >> 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 |