Speed of Light: A universal Constant?
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From: Henri Wilson on 27 Mar 2005 19:40 On Sat, 26 Mar 2005 01:36:41 +0000 (UTC), bz <bz+sp(a)ch100-5.chem.lsu.edu> wrote: >H@..(Henri Wilson) wrote in >news:n61941pfr1ceea1mq77i8o1l3d3s01hghh(a)4ax.com: > >>> >>>how do you get different photons to move at different speeds with >>>respect to a single frame of reference? >> >> Why shouldn't they? (in pure vacuum) > >because photons always travel at the speed of light, which is constant. There is no such animal as 'speed of light' or 'speed of anything' for that matter. Speed must be specified relative to something else. > >> >>> >>>Why, when we measure the speed of those photons, do the photons seem to >>>move at the same speed? >> >> Silly boy. Nobody has measured the OW speed of light under any >> circumstance. > >Define 'one way speed of light'. >I fire a laser pulse at two detectors, 1 at 1 meter and 1 at 10 meters from >the laser. I have a timer located mid way between the two detectors. > >When the pulse hits the first detector, it starts the timer >When the pulse hits the second detector, it stops the timer. > >Taking into account all the propagation delays, I calculate the time that >it took the light pulse to travel between detector 1 and detector 2. > >Why is this not the 'one way speed of light'??? Ask any of your SRian colleagues. Clue: How do you synchronize the separated clocks? >>>How distant must the source be? Why must it be distant? I can't see any >>>reason that photons from a distance source should be different from >>>those from a nearby source. >> >> The effect will only work in a pure vacuum....far purer than anything we >> can produce here. > >Oh, that makes it nice. I can claim a special effect that can only be >measured when the moon is full and in the constellation 'southern cross'. >You can't disprove my claim because the moon is never in the constellation >when it is full. [it is, in fact, never in the southern cross.] unrelated drivel. > >> >>> >>>In my mind, 5 feet is distant compared to the wavelength of light. Will >>>you allow me to call 5 feet 'distant'? >> >> ULF wavelengths are longer. >> They are EM. > >ULF? Do you mean UHF? ULF would be ultra low frequency, and we would be >talking about wavelengths in the thousands of km. Well, ain't that longer that 5 feet? > >What does that have to do with light? We were talking about light, weren't >we? Why did you suddenly jump to talking about 196.7 MHz (lamda=5 ft). >Lets get back to light. 5 feet is about 3 million wavelengths for 500 nm >light. That seems 'distant' to me. Sorry, you aren't making much sense. It was YOU who raised the 5 feet issue, not I. HW. www.users.bigpond.com/hewn/index.htm Sometimes I feel like a complete failure. The most useful thing I have ever done is prove Einstein wrong.
From: Sam Wormley on 27 Mar 2005 21:45 Henri Wilson wrote: > On Fri, 25 Mar 2005 23:29:16 GMT, Sam Wormley <swormley1(a)mchsi.com> wrote: >> >> And light moves at 'c' wrt its observers! > > And which experiment demonstrates that? All of them to date!
From: Sam Wormley on 27 Mar 2005 21:48 Henri Wilson wrote: > Sometimes I feel like a complete failure. > The most useful thing I have ever done is prove Einstein wrong. There has NEVER been a prediction of SR or GTR that was contradicted by an observation. NEVER!
From: bz on 27 Mar 2005 21:54 H@..(Henri Wilson) wrote in news:i9ke41pi6c62gfr6mkb14efoeher4odrg4(a)4ax.com: > On Sat, 26 Mar 2005 01:36:41 +0000 (UTC), bz > <bz+sp(a)ch100-5.chem.lsu.edu> wrote: > >>H@..(Henri Wilson) wrote in >>news:n61941pfr1ceea1mq77i8o1l3d3s01hghh(a)4ax.com: >> >>>> >>>>how do you get different photons to move at different speeds with >>>>respect to a single frame of reference? >>> >>> Why shouldn't they? (in pure vacuum) >> >>because photons always travel at the speed of light, which is constant. > > There is no such animal as 'speed of light' or 'speed of anything' for > that matter. Speed must be specified relative to something else. Light travels at c relative to any observer. >>>>Why, when we measure the speed of those photons, do the photons seem >>>>to move at the same speed? >>> >>> Silly boy. Nobody has measured the OW speed of light under any >>> circumstance. >> >>Define 'one way speed of light'. You still haven't defined the 'one way speed of light'. >>I fire a laser pulse at two detectors, 1 at 1 meter and 1 at 10 meters >>from the laser. I have a timer located mid way between the two >>detectors. >> >>When the pulse hits the first detector, it starts the timer >>When the pulse hits the second detector, it stops the timer. >> >>Taking into account all the propagation delays, I calculate the time >>that it took the light pulse to travel between detector 1 and detector >>2. >> >>Why is this not the 'one way speed of light'??? > > Ask any of your SRian colleagues. I ask you because you made the claim that the doppler effect was due to changes in speed of light rather than changes in wavelength. > > Clue: How do you synchronize the separated clocks? In my experiment there is no need for separated clocks. >>>>How distant must the source be? Why must it be distant? I can't see >>>>any reason that photons from a distance source should be different >>>>from those from a nearby source. >>> >>> The effect will only work in a pure vacuum....far purer than anything >>> we can produce here. >> >>Oh, that makes it nice. I can claim a special effect that can only be >>measured when the moon is full and in the constellation 'southern >>cross'. You can't disprove my claim because the moon is never in the >>constellation when it is full. [it is, in fact, never in the southern >>cross.] > > unrelated drivel. The claim that the effect will only work in a pure vacuum is similar. It means the effect will never be observed. >>>>In my mind, 5 feet is distant compared to the wavelength of light. >>>>Will you allow me to call 5 feet 'distant'? >>> >>> ULF wavelengths are longer. >>> They are EM. >> >>ULF? Do you mean UHF? ULF would be ultra low frequency, and we would be >>talking about wavelengths in the thousands of km. > > Well, ain't that longer that 5 feet? Yes, but what did it have to do with my question as to what you considered to be 'distant'. >>What does that have to do with light? We were talking about light, >>weren't we? Why did you suddenly jump to talking about 196.7 MHz >>(lamda=5 ft). Lets get back to light. 5 feet is about 3 million >>wavelengths for 500 nm light. That seems 'distant' to me. > > Sorry, you aren't making much sense. It was YOU who raised the 5 feet > issue, not I. I was trying to extablish what you consider 'at a distance'. because you said the 'light changes speed rather than wavelength' can only be observed at a distance. I asked if 5 feet was far enough when talking about light. If you say NO, I will ask why not. If you say YES, then we can go into the lab and test your theory. So how far is 'distant'? -- 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: Tom Roberts on 27 Mar 2005 23:29
Sam Wormley wrote: > There has NEVER been a prediction of SR or GTR that was contradicted > by an observation. NEVER! I would not say that so unconditionally -- there are numerous observations that at least appear to contradict SR or GR. And there are some phenomena that call into question the validity of GR. For instance: dark matter dark energy the anomalous acceleration of the Pioneer and other spacecraft As far as I am concerned, the scientific jury is still out on these (and probably will be for some time...). But I can say that there have been no reliable and reproducible experiments or observations that contradict SR within its domain of applicability. Tom Roberts tjroberts(a)lucent.com |