Speed of Light: A universal Constant?
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From: bz on 30 Mar 2005 03:03 H@..(Henri Wilson) wrote in news:rquj41lbmant4unh16f4c7aje45363aiqq(a)4ax.com: >>I know the wave is launched from a moving source, an LED at the end of a >>moving fan blade. >> >>I start a timer when the photons from the LED pass the first detector. >>I stop timer and report time when the photons from the LED reach the >>second detector. >> >>I know distance between detectors. >>I know time >>speed = distance/time > > How long does it take the signal from the second LED to stop the timer? 1) this should be how long does it take the signal from the FIRST LED to stop the timer? > Answer: D/(light speed). right. > You cannot be sure light speed is the same in both directions. That is > what you are trying to determine. There is NOT two directions. There is only one direction. moving source of photons second detector >>-----------------------|-----------------------------| << first detector above is a diagram of the test set up. On the left is a spinning fan with an LED at the end of one fan blade. In the center is a half silvered mirror that deflects half the passing photons to a detector, on the right is a second detector that detects the rest of the photons. in between the LED and the first detector there are a couple of pin holes to make sure that we only see photon that are emitted when the LED is travelling straight toward the detectors. We are measuring time it takes the light to pass from the first detector to the second detector. We are using one clock to do this. The light travels only one direction. This is the one way speed of light. > > You have described a typical TWLS experiment. there is NO two way light. The light only travels one direction. > >> >>I have just measured the time. >> >>What is so hard about that????? >>Where is there a flaw in the experiment? > > You don't understand anything. I can count to two. In this case there is only one way. Where is the flaw in the experiment? -- 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: kenseto on 30 Mar 2005 08:49 "Tom Roberts" <tjroberts(a)lucent.com> wrote in message news:tOn2e.12443$ZB6.10706(a)newssvr19.news.prodigy.com... > kenseto wrote: > > "Tom Roberts" <tjroberts(a)lucent.com> wrote in message > > news:d2bqi2$fns(a)netnews.proxy.lucent.com... > >>I rigidly nailed both clocks to the surface of the earth, so there is no > >>vertical motion of either clock, "absolute" or otherwise (and I wait > >>until there is no earthquake (:-)). > > > > Sigh....absolute motion is that motion of the distant clock in the vertical > > direction wrt the defined horizontal light ray. > > There is no such motion not shared by the other clock. And whatever such > motion you care to ascribe to the clocks will also apply to the light beam. The light beam moves in the horizontal direction where it is aimed. The reason why the light beam can hit the vertically moving target is because the speed of light is much higher than the target. There is a difference between an OWLS and a TWLS measurement. For a TWLS measurement: The source clock will record the departure time (tA1) of the leading edge of the light ray or the departure time of the first light pulse. It will record the time (tA2) when a later light pulse (not the first light pulse) return to the source clock. The flight time is (tA2-tA1) and TWLS=c=2L/(tA2-tA1). For an OWLS measurement: The source clock will record the departure time (tA1) of the leading edge of the light ray or the departure time of the first light pulse. The B clock will record the arrival time (tB1) of some later light pulse (not the first light pulse). The flight time is (tB1-tA1) and OWLS=isotropic (but not c)=L/(tB1-tA1). The reason why OWLS is not equal to TWLS is beacuase (tA2-tA1) =/= 2(tB1-tA1) Why? Because with the TWLS measurement the source clock will only miss the first portion of the return light beam. Whereas with an OWLS measurement the first portion of each light beam will miss the target clock B and thus gives a different flight time than 1/2 that of the TWLS measurement. In any case, there is no need for speculation. We can determine the existence of absolute motion by doing the experiment described in the following link (page 3): http://www.journaloftheoretics.com/Links/Papers/Seto.pdf > > > >>All of the light rays hit the detector. I aimed them so this is true. > > > > Your assertion would mean that the leading edge of the light ray (the first > > photon in a train of photons) will hit the detector. This assertion will > > violate the Uncertainty Principle. > > You clearly don't understand photons, and your claim is without basis -- > all you seem to have done is parrot a phrase without understanding it. Your hand waving is not an arguement. We can settle this by doing the experiment in the above link. > > Experimentally, the light from a laser can be formed into pulses with > durations on the order of a femtosecond, and these pulses can be > detected. Sure it can be detected but there is no way to ensure that the pulse you detected is the first pulse generated by the source. Furthermore, detecting a specific individual short pulse like that would still be violating the Uncerttainty Principle. >That is MUCH shorter duration than differences measured in > gravitational redshift experiments, so your notion of "the first part of > the beam misses the detector" as an explanation for gravitational > redshift is refuted by experiments. No it doesn't. Ken Seto But
From: Sam Wormley on 30 Mar 2005 09:12 kenseto wrote: > The reason why OWLS is not equal to TWLS is beacuase > (tA2-tA1) =/= 2(tB1-tA1) > Why? Because with the TWLS measurement the source clock will only miss the > first portion of the return light beam. Whereas with an OWLS measurement > the first portion of each light beam will miss the target clock B and thus > gives a different flight time than 1/2 that of the TWLS measurement. > Seto fails to realize that all measurement of light speed are the same!
From: Tom Roberts on 30 Mar 2005 09:28 kenseto wrote: > "Tom Roberts" <tjroberts(a)lucent.com> wrote in message > news:tOn2e.12443$ZB6.10706(a)newssvr19.news.prodigy.com... >>There is no such motion not shared by the other clock. And whatever such >>motion you care to ascribe to the clocks will also apply to the light >> beam. > > The light beam moves in the horizontal direction where it is aimed. Go back and read Galileo. Since his time we have known that in a moving ship the aiming of a light source at a detector accounts for whatever motion the ship may have, because it is common to source, detector, and light beam. Ditto for throwing balls or firing machine gun bullets. > The > reason why the light beam can hit the vertically moving target is because > the speed of light is much higher than the target. But the relationships do not change -- if the source was mis-aimed so the start of the beam missed the detector, then the entire beam would do so. Smart experimentalists would notice this and would adjust the aim of the source so it does indeed hit the detector. In fact, here on earth you can do this aiming completely geometrically, and hit the detector the very first time you turn the source on. > There is a difference between an OWLS and a TWLS measurement. > For a TWLS measurement: > The source clock will record the departure time (tA1) of the leading edge of > the light ray or the departure time of the first light pulse. It will record > the time (tA2) when a later light pulse (not the first light pulse) But no pulses are lost, so your entire discussion is flawed. You have very fundamental misconceptions about how the world actually works. >>Experimentally, the light from a laser can be formed into pulses with >>durations on the order of a femtosecond, and these pulses can be >>detected. > > Sure it can be detected but there is no way to ensure that the pulse you > detected is the first pulse generated by the source. You did not understand my point. You claim that gravitational redshift is "caused" by the first portion of a light signal not being detected (because it "misses the detector" in some mysterious way); let's call the amount of delay in the detection of the light pulse t0. But a similar light pulse that is much shorter than t0 _IS_ detected. So it cannot be true that the first case was delayed by t0 due to that initial portion of the light pulse "missing the detector" because in the second case that would imply that the entire pulse missed the detector, contrary to observation. Your entire discussion is flawed: real light sources _CAN_ be aimed at detectors, and no light pulses are lost. > Furthermore, detecting > a specific individual short pulse like that would still be violating the > Uncerttainty Principle. I repeat: you do not understand this. _REAL_ experiments show your claim is false, and such short light pulses _CAN_ be detected. And are. [Don't expect me to repeat what I have already said.] Tom Roberts tjroberts(a)lucent.com
From: Jonathan Silverlight on 30 Mar 2005 15:09
In message <d274op$7ph$1(a)news.freedom2surf.net>, George Dishman <george(a)briar.demon.co.uk> writes snip >Stan's calculation is valid but it is just repeating >Roemer's calculation of the speed of light. It proves >Ralph Sansbury wrong but not SR. I'm surprised he hasn't posted to this thread already! Am I the only one who is reminded of Philip Latham's short story "The Xi Effect", where two astronomers get a very unexpected result when they repeat Roemer's experiment? His story is horribly plausible now we know about "branes" and the extra dimensions of string theory. -- Remove spam and invalid from address to reply. |