A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: Ste on 13 Feb 2010 12:51 On 13 Feb, 16:24, kenseto <kens...(a)erinet.com> wrote: > On Feb 13, 8:29 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > I've been absolutely racking my brain (to the point of getting a > > headache) for the last few days about this issue, and it's clear that > > the speed of light (where light is either considered in the form of a > > ballistic photon, or a wave-cycle) cannot, physically, be constant in > > all relative frames, and at the same time be constant when travelling > > between two objects in two different frames. It's a physical and > > logical impossibility. > > The speed of light is a constant math ratio in all frames as follows: > Light path length of the observer's physical ruler (299,792,458 m > long) is assumes to be its physical length/the absolute time content > for a clock second co-moving with the ruler. But even if this were the case, it fails to account for *why* anything would physically contract. > > It's also clear that velocities cannot be additive (in the form of > > speed of bullet+speed of gun), > > Yes the speed of light is not additive....the reason is that light is > being transmitted by a medium occupying all of space. I dare say this medium *is* space. > >and nor can they be subtractive > > relative to a background medium (in the form of speed of propagation > > in medium-speed of source). > > Yes the speed of light is not substractive becasue light is being > transmitted by a medium occupying all of space. What this mean is that > the speed of light in a medium is independent of the motion of the > source. However the arrival speed of light to an observer from a > moving source is dependent on the rate of arrival of frequency of > light waves from a moving source such as sodium is as follows: > 1. The universal wavelength of sodium=589 nm. > 2. The arriving speed of light from a moving sodium dource is: > c'=(measured incoming frequency of sodium light)(universal wavelength > of sodium 589nm) > > I hope the above will resolve your problems. Not really. I'm still struggling to understand what is happening physically to explain these phenomena (which is not helped by the dearth of interest in physics in physical, rather than mathematical, explanations).
From: mpalenik on 13 Feb 2010 13:29 On Feb 13, 12:28 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 13 Feb, 15:04, Sam Wormley <sworml...(a)gmail.com> wrote: > > > On 2/13/10 7:29 AM, Ste wrote: > > > > I've been absolutely racking my brain (to the point of getting a > > > headache) for the last few days about this issue... > > > Physics FAQ:http://math.ucr.edu/home/baez/physics/index.html > > http://math.ucr.edu/home/baez/physics/Relativity/SR/velocity..html > > It's a shame that the only diagram - which enforces the rigor of > giving a physical explanation - was in relation to classical mechanics. We already established in the other thread that using a different coordinate system can change a length of an object in the first frame without changing the length of the object in its own frame. You can see that from the pictures I uploaded. If you look at those pictures, you'll see that the rod in the x', t' frame appears to be longer in the x, t frame. You'll also see that anything that you put in the x,t frame will appear longer in the x',t' frame (if we were to use Minkowski spacetime, the lengths would have contracted, rather than expanded). It turns out that if lengths contract and time dilates as predicted by relativity, the measured speed of light will be constant. That's how those formulas were derived. Einstein said "what would it take for the speed of light to appear constant in all frames," and it turns out the answer is that lengths have to be measured differently and clocks have to run differently. You keep asking why--what's the physical *reason* that lengths are measured differently and clocks run differently, and once again, it's all down to a choice of coordinate system. Why does a moving observing use a different coordinate system than one who isn't moving? Because that's the *definition* of moving. Moving simply *means* that you've rotated your x and t axis. That even explains why the distance between two objects changes when they are moving with respect to one another. If they both have different x and t axes, then they will get farther apart as they each move along their t axis.
From: Sam Wormley on 13 Feb 2010 13:31 On 2/13/10 10:24 AM, kenseto wrote: > > The speed of light is a constant math ratio in all frames as follows: > Light path length of the observer's physical ruler (299,792,458 m > long) is assumes to be its physical length/the absolute time content > for a clock second co-moving with the ruler. I can come up with an infinite number of ratios to come up with the nine digits from the human definition of the speed of light! The real point is that the speed of light is a PHYSICAL CONSTANT observed in nature. How it is defined and what numbers we humans assign to the speed of light is arbitrary! Units of distance are DERIVED from the speed of light, not the other way around.
From: Sam Wormley on 13 Feb 2010 13:32 On 2/13/10 11:23 AM, bert wrote: > > Photons if ever slowed begs this question What energy brings them back > to c? Photons ONLY exist propagating at c, Herb!
From: BURT on 13 Feb 2010 13:33
On Feb 13, 10:29 am, mpalenik <markpale...(a)gmail.com> wrote: > On Feb 13, 12:28 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > On 13 Feb, 15:04, Sam Wormley <sworml...(a)gmail.com> wrote: > > > > On 2/13/10 7:29 AM, Ste wrote: > > > > > I've been absolutely racking my brain (to the point of getting a > > > > headache) for the last few days about this issue... > > > > Physics FAQ:http://math.ucr.edu/home/baez/physics/index.html > > > http://math.ucr.edu/home/baez/physics/Relativity/SR/velocity.html > > > It's a shame that the only diagram - which enforces the rigor of > > giving a physical explanation - was in relation to classical mechanics. > > We already established in the other thread that using a different > coordinate system can change a length of an object in the first frame > without changing the length of the object in its own frame. You can > see that from the pictures I uploaded. > > If you look at those pictures, you'll see that the rod in the x', t' > frame appears to be longer in the x, t frame. You'll also see that > anything that you put in the x,t frame will appear longer in the x',t' > frame (if we were to use Minkowski spacetime, the lengths would have > contracted, rather than expanded). > > It turns out that if lengths contract and time dilates as predicted by > relativity, the measured speed of light will be constant. That's how > those formulas were derived. Einstein said "what would it take for > the speed of light to appear constant in all frames," and it turns out > the answer is that lengths have to be measured differently and clocks > have to run differently. > > You keep asking why--what's the physical *reason* that lengths are > measured differently and clocks run differently, and once again, it's > all down to a choice of coordinate system. Why does a moving > observing use a different coordinate system than one who isn't > moving? Because that's the *definition* of moving. Moving simply > *means* that you've rotated your x and t axis. That even explains why > the distance between two objects changes when they are moving with > respect to one another. If they both have different x and t axes, > then they will get farther apart as they each move along their t axis. You can travel behind light. Light moves ahead of you slower. But they diverge in distance. Mitch Raemsch |