Simultaneous events and Einstein's absolute time
in [Relativity]
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From: Igor on 2 Feb 2010 17:08 On Feb 2, 12:08 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 2 Feb, 16:06, Jerry <Cephalobus_alie...(a)comcast.net> wrote: > > > On Feb 1, 5:44 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > On 1 Feb, 18:27, Igor <thoov...(a)excite.com> wrote: > > > > > Absolute time and a finite speed of light are contradictory concepts. > > > > Therefore, since it's easy to demonstrate that light has a finite > > > > speed, absolute time cannot exist. > > > > The same arguments (whether true or not) can also be made from the > > > existence of a finite speed of sound. > > > You are confused by a serious PUN. > > > There exists a demonstrable maximum possible speed of > > communications, designated "c". > > You mean the maximum speed of communications using matter? Somewhat > like how there is a maximum speed of communications using sound waves? But there's not a maximum speed of communications using sound waves. Speed of sound is proportional to the density of the medium and has no theoretical upper bound. > > This constant "c" is a fundamental > > parameter in the specification of the geometric properties of > > spacetime. Since this constant "c" is finite, absolute time does > > not exist, assuming that our universe is correctly described by > > this geometric model. > > And that is a big assumption. Well, it's passed all tests put to it so far. > > Light happens to travel at a speed which is either equal to "c" > > in the sense presented above, or which is so close to "c" that no > > measurement has yet established any detectable difference. This > > "speed of light" is conventionally ALSO designated by "c", which > > represents unfortunate historical baggage reflecting the manner > > in which relativity developed. > > Indeed. > > > Should the speed of light ever be discovered not to precisely > > equal "c" (and there is some controversial evidence that this > > may be the case for high energy gamma rays), this will have NO > > CONSEQUENCE WHATSOEVER in regards to the validity of relativity, > > since the "c" which is the speed of light is not the same "c" > > which determines the properties of spacetime. > > Which is the most absurd drivel I've ever heard. What you're basically > saying is that the validity of relativity is independent of any > measurement of the validity of its terms. No, relativity is based on a constant c which may or may not represent the speed of actual radiation in vacuum. All that's sufficient to state is that c is the maximal attainable speed possible. That's what leads to the predictions of SR, not necessarily that c must be the actual speed of electromagnetic radiation in vacuum, although for the most part, it still holds up. But it really doesn't have to. They're two entirely different issues. > To be honest I don't think anyone challenges the validity of > relativity as a mathematical tool. What they challenge are the > philosophical inferences drawn from it - some people appear to be very > skilled with the maths relativity (I personally have no idea how to > apply it mathematically), and yet have no contact with physical > reality. > > When anyone asks "what is the physical basis of relativity", they're > either met by blank stares or angry challenges about the meaning of > "physical" or just an attitude on the part of the "expert" that the > physical basis is inconsequential for the theory. Oh, I don't know. Both the Einstein field equations of GR and Maxwell's equations of EM provide a pretty concrete physical basis of relativity. I think alot of this talk gets started surrounding the Lorentz transformation, which is nothing more than a simple mathematical coordinate transformation. Nothing physical there. It's the invariant snd covariant elements that are transformed by the LT that, more often than not, are physical quantities. Unfortunately, you don't hear much about these on this particular newsgroup, owing to the fact that many people posting here know nothing about the subject beyond their own twisted understanding of the LT. > It's this arrogance and loss of touch with reality that explains why > we're up to 20-odd "hidden dimensions", because the loss of touch with > reality has left scientists out in the wilderness, with neither the > inspiration nor the intuitive guidance that comes with a connection to > the material world. Well even Einstein said that our understanding of the universe should be "as simple as possible, but no simpler". If it requires 20 hidden curled up dimensions, so be it. But I think we've just begun to scratch the surface on this stuff.
From: Androcles on 2 Feb 2010 17:16 "Igor" <thoovler(a)excite.com> wrote in message news:b0bf0a4c-f6a1-48b8-90e1-c991abdf4846(a)b2g2000yqi.googlegroups.com... No, relativity is based on a constant c which may or may not represent the speed of actual radiation in vacuum. =============================================== No, relativity is based on the absurd assertion that the ``time'' required by light to travel from A to B equals the ``time'' it requires to travel from B to A. No, you have no what you are a babbling about. No, you are an idiot. No, you should learn to read.
From: PD on 2 Feb 2010 18:13 On Feb 2, 11:08 am, Ste <ste_ro...(a)hotmail.com> wrote: > On 2 Feb, 16:06, Jerry <Cephalobus_alie...(a)comcast.net> wrote: > > Should the speed of light ever be discovered not to precisely > > equal "c" (and there is some controversial evidence that this > > may be the case for high energy gamma rays), this will have NO > > CONSEQUENCE WHATSOEVER in regards to the validity of relativity, > > since the "c" which is the speed of light is not the same "c" > > which determines the properties of spacetime. > > Which is the most absurd drivel I've ever heard. What you're basically > saying is that the validity of relativity is independent of any > measurement of the validity of its terms. No, that's not right. The fundamental physical basis for relativity is the hyperbolic structure of spacetime and the principle of relativity. It is certainly possible to create a theory of electrodynamics that has a massive photon -- that is, light that travels at a speed v<c -- and which still respects those bases of relativity. It just wouldn't be the Maxwell theory of electrodynamics (nor, if you prefer, QED). However, such a theory has been proposed and would be resurrected if there were ever evidence that the photon mass were nonzero. I'll leave it as a homework exercise for you to look up that (fairly well-known) theory, and to look up the catalog of recent experimental work to look for nonzero photon mass. PD > > To be honest I don't think anyone challenges the validity of > relativity as a mathematical tool. What they challenge are the > philosophical inferences drawn from it - some people appear to be very > skilled with the maths relativity (I personally have no idea how to > apply it mathematically), and yet have no contact with physical > reality. > > When anyone asks "what is the physical basis of relativity", they're > either met by blank stares or angry challenges about the meaning of > "physical" or just an attitude on the part of the "expert" that the > physical basis is inconsequential for the theory. Allow me to break your generalization. > > It's this arrogance and loss of touch with reality that explains why > we're up to 20-odd "hidden dimensions", because the loss of touch with > reality has left scientists out in the wilderness, with neither the > inspiration nor the intuitive guidance that comes with a connection to > the material world.
From: Ste on 2 Feb 2010 22:31 On 2 Feb, 19:07, PD <thedraperfam...(a)gmail.com> wrote: > On Feb 2, 10:51 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > On 2 Feb, 13:15, Igor <thoov...(a)excite.com> wrote: > > > > On Feb 1, 10:29 pm, artful <artful...(a)hotmail.com> wrote: > > > > > On Feb 2, 10:44 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > On 1 Feb, 18:27, Igor <thoov...(a)excite.com> wrote: > > > > > > > Absolute time and a finite speed of light are contradictory concepts. > > > > > > Therefore, since it's easy to demonstrate that light has a finite > > > > > > speed, absolute time cannot exist. > > > > > > The same arguments (whether true or not) can also be made from the > > > > > existence of a finite speed of sound. > > > > > Nope .. because the speed of sound is frame dependant > > > > And sound requires a medium. > > > And light requires a medium - we call it "empty space". > > And if this is how you want to define "medium" -- anything that > carries a transmission of any description -- then there is no > argument. But once again, this is not the connotation that physicists > had associated with "medium" when there was much fuss about whether > light was carried in a medium. As far as I'm concerned, space is to light what air is to sound.
From: artful on 2 Feb 2010 22:42
On Feb 3, 2:31 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 2 Feb, 19:07, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > On Feb 2, 10:51 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > On 2 Feb, 13:15, Igor <thoov...(a)excite.com> wrote: > > > > > On Feb 1, 10:29 pm, artful <artful...(a)hotmail.com> wrote: > > > > > > On Feb 2, 10:44 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > On 1 Feb, 18:27, Igor <thoov...(a)excite.com> wrote: > > > > > > > > Absolute time and a finite speed of light are contradictory concepts. > > > > > > > Therefore, since it's easy to demonstrate that light has a finite > > > > > > > speed, absolute time cannot exist. > > > > > > > The same arguments (whether true or not) can also be made from the > > > > > > existence of a finite speed of sound. > > > > > > Nope .. because the speed of sound is frame dependant > > > > > And sound requires a medium. > > > > And light requires a medium - we call it "empty space". > > > And if this is how you want to define "medium" -- anything that > > carries a transmission of any description -- then there is no > > argument. But once again, this is not the connotation that physicists > > had associated with "medium" when there was much fuss about whether > > light was carried in a medium. > > As far as I'm concerned, space is to light what air is to sound. Then you are naive or ignorant. |