A constant speed of light in all reference frames? Surely you can't be serious. [Physics]

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From: JT on 14 Feb 2010 13:33

On 14 Feb, 14:34, mpc755 <mpc...(a)gmail.com> wrote:
> On Feb 14, 1:31 am, "Peter Webb"
>
>
>
>
>
> <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote:
> > "mpc755" <mpc...(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.
>
> As long as any Observer is able to factor in their state with respect
> to the state of the medium in which the light propagates being at rest
> then the Observer is able to conclude when the lightning strikes
> occurred in nature.
Well units is comparisson measurments that is agreed upon, if observer
B,C,D,E,F is travelling different velocities but at moment X all is
aligned parallell in fron of A and all agree on length of object A
the distance to A then you deal with a *UNIT*

Iif B,C,D,E,F all have different distance and length of A they do not
deal with units they deal with ECDT=Einstein compressed diamond turds.
In SR every *inertial frame*=set have it's own flavour of meters can
be banana, cucumber or pretty much any extension you can think of.

Those different flavoured units make the barn and the pole paradox a
joke, actually they make it into turdjuggling.

JT

>
> If an infinite number of Observers in an infinite number of frames of
> reference all exist in the same medium in which the light waves
> propagate and all of the Observers are able to determine their state
> with respect to the state of the medium the light waves propagate
> through being at rest all of the Observers will arrive at the same
> conclusion as to when the lightning strikes occurred in nature.
>
> Even if the Observers themselves do not exist in the same medium in
> which the light waves propagate, as long as every one of the infinite
> Observers are able to factor in the light waves propagating through
> the medium at rest, all of the Observers will arrive as to when the
> lightning strikes occurred in the medium, in nature. All of the
> Observers will arrive at the same conclusion as to when the lightning
> strikes occurred. If an infinite number of Observers all arrive at the
> same conclusion as to when the lightning strikes occurred then the
> infinite number of Observers have determined when the lightning
> strikes occurred in nature.- Dölj citerad text -
>
> - Visa citerad text -

From: Ste on 14 Feb 2010 14:03

On 14 Feb, 05:27, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote:
> Ste 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.
>
> Not true. You are making implicit assumptions that are not valid in the world we
> inhabit.
>
> At base, this is GEOMETRY, not any properties of light itself. And the only way
> to understand it is to study SR and its underlying geometry, Minkowski spacetime.
>
> The primary invalid assumption you make appears to me to be Euclidean geometry.
> But you also implicitly assume that speeds add like vectors; they don't.
>
> Indeed, even this is wrong: "I mean the alternatives are that
> a object's velocity must cause either an increase or a decrease
> in the speed of light in a particular direction relative to
> something."
>
> One does not "reconcile this physically", one reconciles it GEOMETRICALLY..
>
> Speaking VERY LOOSELY, one could say that there are "grooves"
> in spacetime that go in every direction at every point, with
> the speed of light. And light "just happens" to always travel
> in these grooves. The actual geometry is MUCH more interesting,
> but as I keep saying, you must STUDY this -- your "20 questions"
> approach on the internet is woefully inadequate.
>
> Tom Roberts

I'm afraid you're easily satisifed Tom. As I say, I'm not really
interested in learning geometry, or talking about completely
hypothetical "grooves in spacetime".

I want simple answers to what seem to me to be simple physical
questions. As I said on a previous occasion, few here seem to be able
to break out of the notion that something exists independent of
observation.

I want an explanation where, essentially, information travels
instantaneously, but from which I can derive the effects that any
particular observer would observe. It matters not that information
does not, really, travel instantaneously. The point is that I want an
explanation where it *does*, and I can then add on a layer of observer
effects to reconcile it with real observation.

From: Ste on 14 Feb 2010 14:09

On 13 Feb, 20:28, mpalenik <markpale...(a)gmail.com> wrote:
> On Feb 13, 2:11 pm, Ste <ste_ro...(a)hotmail.com> wrote:
>
> > I'm afraid I do not accept that my "choice of mathematical coordinate
> > system" is the explanation for this.- Hide quoted text -
>
> Think of it as your orientation in spacetime. For example, if you're
> facing north, a natural coordinate system is that north is foward and
> east is right. If you walk in a straight line, you'll end up going
> north.
>
> Now, turn 45 degrees. A natural choice of coordinate system is
> northeast is forward and southeast is right. If you walk forward,
> you'll go northeast.
>
> Are you going to tell me that you won't accept that your natural
> choice of coordinate systems is responsible for you ending up in
> different places when you walk forward? It has to do with your
> orientation, whether it's your orientation on the surface of the earth
> or your orientation in spacetime--your orientation depends on what
> happens when you move forward.

Of course I accept that your orientation affects your direction. But
there is nothing magic about perspective.

From: Ste on 14 Feb 2010 14:27

On 14 Feb, 05:56, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au>
wrote:
>
> The poster Ste:
>
> 1. Won't accept mathemetical descriptions of what is happening, because he
> doesn't know enough mathematics to even follow the most simplistic
> explanation of Minkowski space time (in terms of the Euclidean metric with
> an imaginary axis).

Indeed.

> 2. Won't accept non-mathematical descriptions, as he variously says they are
> analogies, they are not "physical", they don't prove anything or (as above)
> he simply doesn't agree.

I will accept non-mathematical descriptions, but they have to be
something realistic.

A "groove in space" is a meaningless physical concept. It's really
just a reformulation of saying "an imaginary line in space", but
couched in purportedly "non-mathematical" language. And if I didn't
know any better I'd be asking questions like "what are the properties
of this groove", "how does it come about", etc., when in fact an
"imaginary line" is easy to deal with, because I recognise it's
abstract non-physical nature, as a representation of a movement that
some real object will make.

> Your use of the word "grooves" was a istake, it will just confuse him more.
> Next he will want to know how to see the grooves. What I think you are
> alluding to is the "light cone" or "causality cone", and it would be better
> if you had used a more standard explanation.

Indeed, it would have, although I also have a distaste for the "light
cone" concept, too.

> > The actual geometry is MUCH more interesting,
> > but as I keep saying, you must STUDY this -- your "20 questions"
> > approach on the internet is woefully inadequate.
>
> > Tom Roberts
>
> Ste has been studying physics for a whole month now!
>
> If he knows:
>
> 1. Enough Euclidean geometry to understand Pythagoras's theorem,
> 2. What an "imaginary number" is, and arithmetic over the complex numbers
> 3. The Newtonian derivation of Energy and Momentum ....
>
> (all of which are taught at secondary school level)
>
> Then he can actually learn the rules of Minkowski space and how they map to
> the formulas of SR for himself in a couple of days effort.
>
> There is no point trying to teach him this on a newsgroup; he needs to learn
> it for himself. There are lots and lots of web pages that do that. Or he
> could buy a book. The real problem I suspect is that he is too lazy to try.

As I said, I'm not that interested in formulas. As you concede, with
next to no effort, I could have formulas coming out of my ears. What
you don't seem to realise is that I don't *want* a mathematical proof,
I want a physical explanation. If you're not interested in a physical
explanation (or don't even understand what I mean by the word), then
fine, but at least acknowledge that I have quite different questions
than you have, which calls for quite different answers, and the only
nexus between the answers you have and the answers I want is that the
answers I want can quite possibly be derived from the answers you have.

From: Ste on 14 Feb 2010 14:33

On 14 Feb, 11:08, "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)

Which is an interesting fact, and something in want of explanation as
far as I'm concerned.

> > 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.

Of course I realise that. The point I'm making is that where you're
dealing with two different frames that are moving relative, the same
object (i.e. the photon, or whatever) cannot physically have the same
measured velocity in both. For sure, a ball can be bounced on a moving
train as it is bounced on the platform, but a ball thrown from the
train to the platform (i.e. what I'm calling "between frames") cannot
possibly move at the same speed relative to the platform as it does
relative to the train.