Speed of Light: A universal Constant?
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From: Lady Chatterly on 1 Apr 2005 09:09 In article <3Tb3e.1147$tI6.789(a)fe2.columbus.rr.com> kenseto <kenseto(a)erinet.com> wrote: > >What you are doing is replacing the speed of light with the speed of signal >through the cable from two different directions. This will guarantee that >your measured speed is less than c because the speed of light is faster than >the speed of the signal through the cable. BTW your procedure is exactly a >TWLS measurement of the speed of the signal through the cables. >> >> > So what you have is a TWLS measurement for >> > delta t. >> > You don't even understand that the cable that carries the signal is not >> > instantaneous. >> >> >> In a previous article in this thread I already addressed this. >> I know how long the cables are and exactly how long it takes a pulse to >get >> from one end to the other. These are peano 's axioms for number theory. >So you are assuming that you know the speed of the signal through the cable >and that's why you know how long it takes a light pulse to get from one end >to the other. You really don't know how stupid this sound?? ....using the >speed of the signal through the cable to measure the speed of light which is >known to be faster than the speed of signal through the cables??? Took a little more adventurous. >Ken Seto Geeze! You too? -- Lady Chatterly "OK, I know I've been away for a while, so maybe I missed something. Is Lady Chatterly a bot?" -- oldami
From: kenseto on 1 Apr 2005 13:45 "bz" <bz+sp(a)ch100-5.chem.lsu.edu> wrote in message news:Xns962B505B24106WQAHBGMXSZHVspammote(a)130.39.198.139... > "kenseto" <kenseto(a)erinet.com> wrote in > news:3Tb3e.1147$tI6.789(a)fe2.columbus.rr.com: > > > >> > >> There is no cable 'that return the signal'. There is one cable between > >> detector 1 and the scope. There is one cable between detector 2 and the > >> scope. There is no return leg. > > > > What you are doing is replacing the speed of light with the speed of > > signal through the cable from two different directions. This will > > guarantee that your measured speed is less than c because the speed of > > light is faster than the speed of the signal through the cable. BTW your > > procedure is exactly a TWLS measurement of the speed of the signal > > through the cables. > > I am measuring the difference in time between two signals. One coming down > each cable. > > As long as the time in the cable is the same for both signals, the > difference is measured correctly. Hey idiot...the difference is the time interval needed for the signal to move from one detector to the other. What this mean is that you are measuring the speed of the signal through the cables. Ken Seto > > >> > >> > So what you have is a TWLS measurement for > >> > delta t. > >> > You don't even understand that the cable that carries the signal is > >> > not instantaneous. > >> > >> > >> In a previous article in this thread I already addressed this. > >> I know how long the cables are and exactly how long it takes a pulse to > > get > >> from one end to the other. > > > > So you are assuming that you know the speed of the signal through the > > cable > > NO! I KNOW the speed because I can measure it. > > TDR, time domain reflectometers will tell you how long a cable is in time > units and length units(once you account for the velocity factor of the > cable). > > But, as I have said, I don't need to know the length of the cable or the > propagation speed, I only need to know that it is constant. > > > and that's why you know how long it takes a light pulse to get > > from one end to the other. You really don't know how stupid this sound?? > > I know exactly how stupid it sounds. > Have you ever used an oscilliscope? > > > > ....using the speed of the signal through the cable to measure the speed > > of light which is known to be faster than the speed of signal through > > the cables??? > > The signal through the cable could move at 1% of the speed of light. It > doesn't matter. Both cables are the same length. That can be tested by > swapping the cables. > > t2+cable2delay - t1+cable1delay = t2-t1 > provided that cable2delay=cable1delay > I am interested in t2-t1 as I vary the rotation rate (speed) of the source. > > I am measuring owls from a moving source. > > The source moves toward the detectors for a very short time during each > revolution of the shaft that the light source is mounted on. > > You still have failed to point out any real flaws in the experiment. > If there was a gross error, a bunch of people would have jumped in and > pointed it out. So far the ONLY rational objection was that the source > speed might be too slow to clearly show relativistic effects. Since I am > not trying to show such effects, just to show that the doppler effect is > NOT due to changes in the speed of light, I don't think there is a problem. > > If we want relativistic effects, we might substitute a rotating beam of > eletrons for the LED on a rotating device. > > In any case, we can use the 'time of flight' measurement of the beam of > photons to verify that the speed of light has not been changed by the > velocity of the source of the light. > > [aside: did you know that time-of-flight is used to measure the mass of > atoms?] > > > -- > 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: Sue... on 1 Apr 2005 14:14 bz, I am just now learning some of the shorthand used in this NG. You probably have already figured out that "hey idiot" means you have made your point and the other person isn't willing to admit it. Unless you are fond of profanity, be very careful not to post this link in these one/two way SOL discussions. ;-) http://www.boulder.nist.gov/timefreq/time/commonviewgps.htm Sue...
From: bz on 1 Apr 2005 14:19 "kenseto" <kenseto(a)erinet.com> wrote in news:HFg3e.1282$Fh4.780 @fe2.columbus.rr.com: >> I am measuring the difference in time between two signals. One coming down >> each cable. >> >> As long as the time in the cable is the same for both signals, the >> difference is measured correctly. > > Hey idiot...the difference is the time interval needed for the signal to > move from one detector to the other. What this mean is that you are > measuring the speed of the signal through the cables. > If I am an idiot, I am not the only one. Here is an experiment similar in some ways to part of mine experiment. http://artemis.austincollege.edu/acad/physics/lrobin/lightspeed%20exp.pdf Please note: I am NOT calling you names. Please do not call me names. Not that they hurt my feelings, but calling people names makes YOU look bad. The difference is the time interval needed for the PHOTONS to move from one detector to the other. There is nothing else moving from one detector to the other. The photon travel time is the "signal" that I am measuring. Have you ever used an oscilliscope? Since you keep ignoring the question, I am beginning to suspect that the answer is no. -- 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: Randy Poe on 1 Apr 2005 14:48
kenseto wrote: > Hey idiot...the difference is the time interval needed for the signal to > move from one detector to the other. What this mean is that you are > measuring the speed of the signal through the cables. > Look at this equation: > > t2+cable2delay - t1+cable1delay = t2-t1 > > provided that cable2delay=cable1delay They both have the same cable delay, achieved by using the same length cable. When you subtract the two times, you measure t2-t1, even if the cables were a light year long and the signal arrived at your scope a year after they hit the detectors. Let us suppose t2-t1 is one msec, and my cable transit time is one year. Then my first signal will arrive at the scope at t1 plus one year, and the second will arrive at t1 plus one year plus one msec. The difference is one msec. That is *NOT* "measuring the speed of the signal through the cable". - Randy |