A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: mpalenik on 21 Feb 2010 20:12 On Feb 21, 8:01 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > For example, Kepler, while not really a physicist per-se, devised > > descriptions of the elliptical orbits that planets must follow. > > A description which in fact they don't follow, hence the need for GR. > > > Newton, then, discovered that this is a special case of the > > conservation of angular momentum, which is a much more general > > principle--however, conservation of angular momentum MUST be able to > > reproduce the elliptical orbits of planets, or else it is wrong. > > Kepler's rules constrained Newton's theories. > > > Special relativity then changed Newton's laws, a bit. The basic > > principles, like F = dp/dt remained, but Special relativity says that > > space and time must transform differently than they do in Newtonian > > mechanics. However, Newtonian mechanics is still a special case of > > special relativity--as the speed of an object approaches zero, the > > laws begin to reproduce Newton's laws. > > In other words "Newtonian mechanics are valid, as long as nothing is > moving". Which somewhat defeats the purpose of mechanics, which is to > describe movement, no? I think you're rewriting history Mark. > No, you are completely misunderstanding this. It almost seems deliberate. SR must have Newtonian mechanics as a limiting case. That is, as speed->0 SR must approach Newtonian mechanics. If SR approaches something OTHER than newtonian mechanics when speed goes to zero, then it is wrong. But the equations of SR *DO* approach the equations of Newton when speed goes to zero. This is not a tough concept. > > Newton's laws, in this way, > > constrain Special Relativity. Because if it did *NOT* reproduce > > Newton's laws at low speeds, it would be wrong. > > > General relativity came along and it turns out that special relativity > > only works as a limiting case of general relativity, specifically, > > when there is no mass or energy present. As the amount of mass and > > energy present goes to zero, general relativity reproduces special > > relativity. If it could not do this, it would be wrong. > > In other words, SR is correct until it is applied to anything real. > Again, given that science is supposed to describe reality... No, the equations of GR approach the equations of SR as the stress energy tensor goes to zero. If they approached some other set of equations as the stress energy tensor went to zero, it would be wrong. It is entirely possible that you could make a theory that *doesn't* reproduce the equations of SR when the stress energy tensor goes to zero. Such a theory would be wrong. > > > Any new physics must be able to reproduce the old physics in the > > regimes in which it has been tested. Any new theory that cannot do so > > is necessarily wrong because it has already been ruled out by > > experiment. > > > There's no way to know whether at some higher energy or smaller > > distance than we've observed the laws of physics actually are > > different than what we believe. But even so, these new laws must > > reduce to the old ones at lower energies and larger distances. > > I don't think there is any necessity that new laws encompass the old, > so long as the new law is consistent with data. The new law can't be consistant with the data without encompasing the old. that's the whole point.
From: Ste on 21 Feb 2010 20:13 On 22 Feb, 00:47, mpalenik <markpale...(a)gmail.com> wrote: > On Feb 21, 7:42 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > On 21 Feb, 22:28, mpalenik <markpale...(a)gmail.com> wrote: > > > > On Feb 21, 4:57 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > On 21 Feb, 01:45, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > > > > wrote: > > > > > > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > > > > > > On 20 Feb, 05:27, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > > > > > > wrote: > > > > > >> If you're suggesting that it's improbable that a theory could work not > > > > > >> because its premises were correct, but because it simply promoted > > > > > >> correct behaviours, then wonders why religion has fared so well. In > > > > > >> any event, I'm willing to accept Feynman's argument, basically that QM > > > > > >> amounts to a workable mathematical model, and makes no claim to any > > > > > >> truth more fundamental than that. > > > > > > >> ________________________________ > > > > > >> The whole of physics is like that, not just QM. Physics just gives us the > > > > > >> eqns by which the universe functions. It does not make claim to any more > > > > > >> truths fundamental than the eqns; the rest is just philosophy. > > > > > > >> Your problem of course is that you don't understand the eqns, so you > > > > > >> don't > > > > > >> understand physics. > > > > > > > On the contrary, my problem is that physics seems to have dispensed > > > > > > with the physical. Yet it is the physical, as opposed to the > > > > > > mathematical, that I am interested in. That is, the qualitative > > > > > > physical concepts - what I've referred to as an explanation at the > > > > > > the "practical-mechanical" level - that would seem to me to > > > > > > distinguish physics from maths are largely absent, and indeed seem to > > > > > > be systematically deprecated and devalued. > > > > > > You should look up, and learn, Minkowski space time. This gives a > > > > > practical/mechanical explanation of SR that most physicists find very easy > > > > > to use and understand. However even simple explanantions do involve high > > > > > school mathematics. Like I said, it can only be "dumbed-down" so far. > > > > > Peter, will you please stop treating me as an idiot, as though I > > > > somehow don't understand the nature of Minkowski spacetime. > > > > You don't. What makes it Minkowski spacetime? How do space and time > > > behave under rotation in a way that is different from a rotation in > > > non-Minkowskian spacetime? What shape is a curve made up of points > > > equidistant from the origin? Why is it different from regular, > > > euclidean space? What is it about a moving object that makes it look > > > like it's rotated in a 4 dimensional, Minkowskian manifold? > > > I've no idea, but I know none of it has any connection with a > > "practical-mechanical explanation". > > It actually does, you simply don't accept that reality works that > way. What you want is an explanation that: > 1) Physically describes what is happening > and > 2) conforms to your preconcieved notions about how reality works. > > 1) is possible but there does not and *cannot* exist an explanation > that satisfies 2). I think you overestimate the degree to which I have "preconceived notions". The only substantial requirements of my "preconceptions" are that a theory is philosophically realistic/materialistic, that it works with the existing 4 dimensions, that it gives an observer- and measurement-independent description, and that things relate in a broadly mechanistic way (i.e. in a way that is broadly compatible with classical mechanics).
From: mpc755 on 21 Feb 2010 20:15 On Feb 21, 2:01 pm, JT <jonas.thornv...(a)hotmail.com> wrote: > On 21 Feb, 18:51, mpc755 <mpc...(a)gmail.com> wrote: > > > > > On Feb 21, 12:43 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > > > > On Feb 21, 11:44 am, mpc755 <mpc...(a)gmail.com> wrote: > > > > > On Feb 21, 11:28 am, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > > > > > > On Feb 20, 11:21 pm, "Peter Webb" > > > > > > <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > > > > > > > And if conducted in a laboratory in low earth orbit, with a relative speed > > > > > > > of 25,000 kph relative to the ether - what will be the measured speed of > > > > > > > light then? > > > > > > > The light will be 'measured' to be 'c'. If the Observers in the > > > > > > laboratory in low Earth orbit know how they are moving with respect to > > > > > > the aether they will be able to determine the speed of light to be 'c' > > > > > > with respect to the aether. > > > > > > > ______________________________________ > > > > > > So, according to you, in every inertial reference frame, the measured speed > > > > > > of light is "c", completely independent of how the observer is moving > > > > > > relative to the ether? > > > > > > He is with good company on this point. Read the 1904 paper by > > > > > Lorentz. > > > > > >http://en.wikisource.org/wiki/Electromagnetic_phenomena > > > > > > "It is to be remarked that the formulae for a system without > > > > > translation are implied in what precedes. For such a system the > > > > > quantities with accents become identical to the corresponding ones > > > > > without accents; also k=1 and l=1. The components of (27) are at the > > > > > same time those of the electric force which is exerted by one > > > > > polarized particle on another." > > > > > > Lorentz showed that the moving observer would measure the speed of > > > > > light to be c in his own frame. Because of this there is no way to > > > > > tell if you are at rest WRT the ether. But that doesn't prevent you > > > > > from translating to the coordinates of another frame. If you just > > > > > consider yourself to be at rest WRT the ether and work it out you get > > > > > the same answer as you get by doing a two step translation from your > > > > > frame to the ether to the other frame. Assuming you are at rest WRT > > > > > the ether gives the same math as SR. > > > > > > Bruce > > > > > I think where I differ from Lorentz is in the 'ticking' rate of atomic > > > > clocks. Two frames are moving relative to one another. I think Lorentz > > > > is saying each Observer in a reference frame 'sees' the other > > > > Observer's clock as 'ticking' slower than their own. This I disagree > > > > with. The more at rest with respect to the aether an atomic clock is > > > > the faster it 'ticks'. If the embankment is at rest with respect to > > > > the aether and the train is moving with respect to the aether then the > > > > clock on the embankment 'ticks' faster than the clock on the train. > > > > But you don't *know* that the embankment is at rest WRT the ether. > > > All you really know is how their clock syncs relate to each other due > > > to their relative motion. > > > Correct. But what about length contraction at speeds near 'c'. Won't > > the train moving near 'c' with its shorter measuring rod measure the > > train at rest with respect to the embankment to be longer and vice > > verse? Where the train at rest with respect to the embankment and its > > longer measuring rod to measure the train moving near 'c' with respect > > to the aether to be shorter? > > Good point since they claim mutual time dilation and their is no > prefered rest frame, how can they even claim that one object should be > the contracted one.... > > Well i asked them so many times, but their theory lack consistency > most paradoxes and answers is just AdHoc speculation and lack total > connection with reality. So i do not expect you to get an answer at > that question. > > JT > That's where Aether Displacement is different. In Aether Displacement everything is with respect to the aether. I discuss the frames of reference as being more, or less, at rest with respect to the aether. I also like Einstein's description of the aether as, "the state of the [ether] is at every place determined by its connections to the matter and the state of the ether in neighboring places". Since the aether exists through out the Earth surrounding each nuclei which is the matter which is the Earth, the aether at the surface of the Earth is at rest, or almost at rest, with respect to the surface of the Earth. If the embankment is at rest with respect to the surface of the Earth and the train is moving with respect to the embankment, the embankment is more at rest with respect to the aether than the train is. If the train is moving relative to the embankment then the frames of reference are not equal because they both do not exist in the same state with respect to the aether. > > I still prefer Einstein's concept of "the state of the [ether] is at > > every place determined by its connections with the matter and the > > state of the ether in neighboring places" versus an 'absolutely > > stationary space'. > > > The state of the aether's displacement is at every place determined by > > its connections with the matter and the state of the aether in > > neighboring places. > > > Since matter and aether are different states of the same material, the > > aether is displaced by the matter. A moving C-60 molecule has an > > associated aether displacement wave. > > > > > The Observer on the embankment and the Observer on the train will > > > > arrive at the same conclusion which is the clock on the embankment > > > > 'ticks' faster than the clock on the train.- Hide quoted text - > > > > > - Show quoted text -- Dölj citerad text - > > > - Visa citerad text -- Dölj citerad text - > > > - Visa citerad text - > >
From: mpalenik on 21 Feb 2010 20:19 On Feb 21, 8:13 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 22 Feb, 00:47, mpalenik <markpale...(a)gmail.com> wrote: > > > > > On Feb 21, 7:42 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > On 21 Feb, 22:28, mpalenik <markpale...(a)gmail.com> wrote: > > > > > On Feb 21, 4:57 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > On 21 Feb, 01:45, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com..au> > > > > > wrote: > > > > > > > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > > > > > > > On 20 Feb, 05:27, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet..com.au> > > > > > > > wrote: > > > > > > >> If you're suggesting that it's improbable that a theory could work not > > > > > > >> because its premises were correct, but because it simply promoted > > > > > > >> correct behaviours, then wonders why religion has fared so well. In > > > > > > >> any event, I'm willing to accept Feynman's argument, basically that QM > > > > > > >> amounts to a workable mathematical model, and makes no claim to any > > > > > > >> truth more fundamental than that. > > > > > > > >> ________________________________ > > > > > > >> The whole of physics is like that, not just QM. Physics just gives us the > > > > > > >> eqns by which the universe functions. It does not make claim to any more > > > > > > >> truths fundamental than the eqns; the rest is just philosophy. > > > > > > > >> Your problem of course is that you don't understand the eqns, so you > > > > > > >> don't > > > > > > >> understand physics. > > > > > > > > On the contrary, my problem is that physics seems to have dispensed > > > > > > > with the physical. Yet it is the physical, as opposed to the > > > > > > > mathematical, that I am interested in. That is, the qualitative > > > > > > > physical concepts - what I've referred to as an explanation at the > > > > > > > the "practical-mechanical" level - that would seem to me to > > > > > > > distinguish physics from maths are largely absent, and indeed seem to > > > > > > > be systematically deprecated and devalued. > > > > > > > You should look up, and learn, Minkowski space time. This gives a > > > > > > practical/mechanical explanation of SR that most physicists find very easy > > > > > > to use and understand. However even simple explanantions do involve high > > > > > > school mathematics. Like I said, it can only be "dumbed-down" so far. > > > > > > Peter, will you please stop treating me as an idiot, as though I > > > > > somehow don't understand the nature of Minkowski spacetime. > > > > > You don't. What makes it Minkowski spacetime? How do space and time > > > > behave under rotation in a way that is different from a rotation in > > > > non-Minkowskian spacetime? What shape is a curve made up of points > > > > equidistant from the origin? Why is it different from regular, > > > > euclidean space? What is it about a moving object that makes it look > > > > like it's rotated in a 4 dimensional, Minkowskian manifold? > > > > I've no idea, but I know none of it has any connection with a > > > "practical-mechanical explanation". > > > It actually does, you simply don't accept that reality works that > > way. What you want is an explanation that: > > 1) Physically describes what is happening > > and > > 2) conforms to your preconcieved notions about how reality works. > > > 1) is possible but there does not and *cannot* exist an explanation > > that satisfies 2). > > I think you overestimate the degree to which I have "preconceived > notions". The only substantial requirements of my "preconceptions" are > that a theory is philosophically realistic/materialistic, that it > works with the existing 4 dimensions, that it gives an observer- and > measurement-independent description, and that things relate in a > broadly mechanistic way (i.e. in a way that is broadly compatible with > classical mechanics). The geometry of Minkowski spacetime does all of those. Minkowski spacetime is: a type of 4 dimensional manifold (works with the existing 4 dimensions) gives a coordinate independent description of objects--they have invariant properties that do not depend on your frame of reference (gives an observer - and measurement-independent description) Still has the principles of force, acceleration, and velocity that were used to characterize Newton's equations (wo The key seems to be that you don't personally consider it philosophically realistic. But you have not even defined what you consider to be philosophically realistic, let alone why a theory should conform to your particular definition.
From: Peter Webb on 21 Feb 2010 20:18
> > > I've no idea, but I know none of it has any connection with a > > "practical-mechanical explanation". > > It actually does, you simply don't accept that reality works that > way. What you want is an explanation that: > 1) Physically describes what is happening > and > 2) conforms to your preconcieved notions about how reality works. > > 1) is possible but there does not and *cannot* exist an explanation > that satisfies 2). I think you overestimate the degree to which I have "preconceived notions". The only substantial requirements of my "preconceptions" are that a theory is philosophically realistic/materialistic, that it works with the existing 4 dimensions, that it gives an observer- and measurement-independent description, and that things relate in a broadly mechanistic way (i.e. in a way that is broadly compatible with classical mechanics). __________________________________ So, how does Minkowski contradict the above? It is philosophically realistic, works with the existing 4 dimensions, provides an observer independent description and reduces to classical mechanics in the limit. It seems to be *exactly* what you want. |