A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: Peter Webb on 14 Feb 2010 01:31 "mpc755" <mpc755(a)gmail.com> wrote in message news:49c69202-f525-4bba-bfa0-09b662433837(a)s33g2000prm.googlegroups.com... On Feb 14, 1:12 am, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > Now, here's the kicker. If the Observers on the train know they are > moving relative to water at rest with respect to the embankment, the > Observers on the train will be able to factor in the trains motion > relative to the water and calculate back and determine the lightning > strikes were in fact, simultaneous with respect to the water > > _______________________________________ > Yes. > > and conclude the lightning strikes were simultaneous, in nature. > > __________________________________________ > No. Nowhere in the 200 lines that preceded this do you show that reference > frame of the water is the reference frame of "nature". It doesn't even > make > any sense. Light propagates at a constant speed with respect to the state of the medium in which it exists. __________________________________________ No. The Observers on the train know their state with respect to the state of the water and are able to conclude correctly the lightning strikes at A/A' and B/B' were simultaneous, in nature. ________________________________ If by "in nature", you mean the "in the frame of reference of the earth considered as an inertial frame", then yes. If "in nature" means something else, perhaps you should explain exactly what "in nature" is supposed to mean.
From: Peter Webb on 14 Feb 2010 03:52 "mpc755" <mpc755(a)gmail.com> wrote in message news:df5fb519-7beb-4edd-af0c-3267b08153e9(a)o3g2000yqb.googlegroups.com... On Feb 14, 1:12 am, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > Now, here's the kicker. If the Observers on the train know they are > moving relative to water at rest with respect to the embankment, the > Observers on the train will be able to factor in the trains motion > relative to the water and calculate back and determine the lightning > strikes were in fact, simultaneous with respect to the water > > _______________________________________ > Yes. > > and conclude the lightning strikes were simultaneous, in nature. > > __________________________________________ > No. Nowhere in the 200 lines that preceded this do you show that reference > frame of the water is the reference frame of "nature". It doesn't even > make > any sense. Light propagates at a constant speed with respect to the state of the medium in which it exists being at rest. ___________________________ Whatever that is supposed to mean. The Observers on the train know their state with respect to the state of the water at rest and are able to conclude correctly the lightning strikes at A/A' and B/B' were simultaneous, in nature. ________________________ Whatever "in nature" is supposed to mean.
From: Inertial on 14 Feb 2010 06:08 "Ste" <ste_rose0(a)hotmail.com> wrote in message news:3a7bc432-defb-4936-b794-236b877d9cc9(a)q29g2000yqn.googlegroups.com... > 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, Why not. it is in SR (which is consistent and correctly predicts what happens in reality) > and at the same time be constant when travelling > between two objects in two different frames. You do realize that points exist in ALL frames. There's no such thing as objects being in two different frames. They are all in every frame. > It's a physical and > logical impossibility. Seems to be from your misunderstanding about frames of reference > It's also clear that velocities cannot be additive (in the form of > speed of bullet+speed of gun), They aren't. Have you even read anything beyond coffee table books ad comics on SR? > and nor can they be subtractive > relative to a background medium (in the form of speed of propagation > in medium-speed of source). > > Take an illustration: > > A C > B > > Where A and B are atoms that pass infinitely close to each other. In > the illustration, A and B are separated from C by a distance L. A and > C are stationary relative to each other. B is moving, and approaching > C at a speed S. A pulse is emitted from both A and B simultaneously > towards C, at the point when A and B are equidistant from C. > > Now, clearly, if velocities were additive, then light from B would > reach C much quicker than light from A. We don't see that, so we can > dismiss that immediately. > > Next, if velocities were subtractive, like sound, well that seems like > a compelling explanation for what we see, which is that light from > both A and B travel towards C at the same speed. But the presence of > an absolute medium seems to fall down when one considers that, to be > consistent with observation, the speed of propagation orthogonal to > the direction of travel must be the same as the speed in the direction > of travel. > > A speed (i.e. a mesure of distance traversed within a period of time) > cannot possibly be measured constant in all directions within a frame, > *and* constant between frames, where the frames themselves are moving > at a speed relative to each other. So how the hell does one reconcile > this physically? Look at SR (or LET)
From: JT on 14 Feb 2010 06:33 On 14 Feb, 12:08, "Inertial" <relativ...(a)rest.com> wrote: > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > news:3a7bc432-defb-4936-b794-236b877d9cc9(a)q29g2000yqn.googlegroups.com... > > > 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, > > Why not. it is in SR (which is consistent and correctly predicts what > happens in reality) > > > and at the same time be constant when travelling > > between two objects in two different frames. > > You do realize that points exist in ALL frames. There's no such thing as > objects being in two different frames. They are all in every frame. I think he you are the one who do not realise that the points intervall and extension must have same magnitude within all frames. They C,D,E,F is at moment X parallell locaded to object A at different velocities, they can not all have different distances to object A and different measures of A's extension into space, because then they variant units between frames, and the barn and pole boils down to banana and cucumber juggling, You are correct though that the objects are in every frame but the local universal frame of SR use variant units making mappings only locally valid, and that is what make barn and the pole so hilarious. JT Let me ask you sir are you a cucumber and banana juggler? > > It's a physical and > > logical impossibility. > > Seems to be from your misunderstanding about frames of reference > > > It's also clear that velocities cannot be additive (in the form of > > speed of bullet+speed of gun), > > They aren't. Have you even read anything beyond coffee table books ad > comics on SR? > > > > > > > and nor can they be subtractive > > relative to a background medium (in the form of speed of propagation > > in medium-speed of source). > > > Take an illustration: > > > A C > > B > > > Where A and B are atoms that pass infinitely close to each other. In > > the illustration, A and B are separated from C by a distance L. A and > > C are stationary relative to each other. B is moving, and approaching > > C at a speed S. A pulse is emitted from both A and B simultaneously > > towards C, at the point when A and B are equidistant from C. > > > Now, clearly, if velocities were additive, then light from B would > > reach C much quicker than light from A. We don't see that, so we can > > dismiss that immediately. > > > Next, if velocities were subtractive, like sound, well that seems like > > a compelling explanation for what we see, which is that light from > > both A and B travel towards C at the same speed. But the presence of > > an absolute medium seems to fall down when one considers that, to be > > consistent with observation, the speed of propagation orthogonal to > > the direction of travel must be the same as the speed in the direction > > of travel. > > > A speed (i.e. a mesure of distance traversed within a period of time) > > cannot possibly be measured constant in all directions within a frame, > > *and* constant between frames, where the frames themselves are moving > > at a speed relative to each other. So how the hell does one reconcile > > this physically? > > Look at SR (or LET)
From: Inertial on 14 Feb 2010 06:40
"JT" <jonas.thornvall(a)hotmail.com> wrote in message news:444e7b76-4ff5-4218-a732-40ef60116be1(a)q21g2000yqm.googlegroups.com... > On 14 Feb, 12:08, "Inertial" <relativ...(a)rest.com> wrote: >> "Ste" <ste_ro...(a)hotmail.com> wrote in message >> >> news:3a7bc432-defb-4936-b794-236b877d9cc9(a)q29g2000yqn.googlegroups.com... >> >> > 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, >> >> Why not. it is in SR (which is consistent and correctly predicts what >> happens in reality) >> >> > and at the same time be constant when travelling >> > between two objects in two different frames. >> >> You do realize that points exist in ALL frames. There's no such thing as >> objects being in two different frames. They are all in every frame. > > I think he you are the one who do not realise that the points > intervall and extension must have same magnitude within all frames. Nope .. they don't need to. [snip nonsense] > You are correct though that the objects are in every frame but the > local universal frame of SR Every frame is universal > use variant units No .. they use the same units in each frame. But that does not mean (nor require) that the units in one frame are the same when measured by other frames. We know experimentally that they aren't. There are, of course, measurements that ARE frame independent, eg proper length of a rod. > making mappings only > locally valid, and that is what make barn and the pole so hilarious. |