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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.


From: mpc755 on 21 Feb 2010 21:06
On Feb 21, 7:01 pm, "Peter Webb"
<webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote:
> "mpc755" <mpc...(a)gmail.com> wrote in message
>
> news:45589ff0-5e7f-4a93-b9b0-2f3157708426(a)m37g2000yqf.googlegroups.com...
> On Feb 21, 9:18 am, "Peter Webb"
>
>
>
> <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote:
> > "mpc755" <mpc...(a)gmail.com> wrote in message
>
> >news:dba2b7ab-670a-473f-a7f3-5447e3f01e53(a)b7g2000yqd.googlegroups.com...
> > On Feb 21, 12:27 am, "Peter Webb"
>
> > <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote:
> > > "mpc755" <mpc...(a)gmail.com> wrote in message
>
> > >news:1c9cf786-36cc-4fce-8b57-7f45f5b88ddd(a)v1g2000yqk.googlegroups.com....
> > > 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?
>
> > > Measured, yes.
>
> > > ____________________________________
> > > OK, is the speed of light measured as 'c' in every inertial reference
> > > frame?
>
> > Measured, yes.
>
> > _______________________________
> > How about the rest of the predictions of SR? Will lengths and times
> > measure
> > according to SR? You have no problem with the 80 foot ladder fitting
> > inside
> > the 40 foot barn, or the twins "paradox" ?
>
> I have already explained to you probably twenty times now the atomic
> clocks 'tick' based upon the aether pressure in which the exist. There
> may be length contraction at speeds near 'c'.
>
> __________________________________
> You have explained this many times. Mine is a slightly differerent question.
> Do you believe the rest of the predictions of SR? Will lengths and times
> measure according to SR? You have no problem with the 80 foot ladder fitting
> inside the 40 foot barn, or the twins "paradox" ?

As far as I know the calculations in terms of time measure according
to SR. However, there is no such thing as 'spacetime'. Time is a
concept. The rate at which clocks 'tick' is based upon the aether
pressure in which it exists.

I am not up to speed on Lorentz contraction. In Aether Displacement,
the aether 'displaces back' at 'c'. So and object moving at close to
'c' might be length contracted due to the time it takes for the aether
to displace back.

What I do not agree with in terms of length contraction is its
relativity. If the garage is at rest with respect to the aether and
the ladder is moving close to 'c' with respect to the aether then if
there is length contraction the ladder will fit into the garage as
long as it continues to move at close to 'c'. If the ladder is at rest
with respect to the aether and the garage is moving close to 'c' with
respect to aether then if there is length contraction, or not, the 80
foot ladder will not fit inside the 40 foot, or less, barn.

Length contraction, if it exists, is moving with respect to the
aether.

For the 21st time, the rate at which clocks 'tick' has nothing to do
with time. If a twin travels very fast in a space ship then the atomic
clock 'ticks' slower due to the increase in the aether pressure
associated with the space ship moving with respect to the aether. The
atoms in the twin in the space ship are also affected by the increase
in aether pressure. If all else is equal the twin on the space ship
may return to Earth and they may even look younger, but the same
amount of time has passed. But who knows what effect the additional
pressure on each and every nuclei in the twin on the space ship will
have on the twin? It might cause the twin on the space ship to age
faster. The whole point of the twin paradox is time actually slows for
the twin in the spaceship. That is incorrect. Time does not change.
Time is a concept.
From: Bruce Richmond on 21 Feb 2010 22:24
On Feb 21, 6:10 pm, mpalenik <markpale...(a)gmail.com> wrote:
> On Feb 21, 4:57 pm, Ste <ste_ro...(a)hotmail.com> wrote:
>
>
>
> > If we were to extrapolate a trend from history, then physics has not
> > yet given us a single equation which describes how the universe
> > functions. It has given us some rules of thumb and some cumbersome
> > approximations.
>
> This just further illustrates that you don't understand how physics
> actually works.  The history of physics isn't a series of blunders
> that we've thrown out as we get better and better equations, hampered
> by our belief in the old equations.  Rather, physics at just about
> every point in time since the renaissance has been a journey from very
> specific to more general rules--criteria by which any new physics must
> be constrained.
>
> For example, Kepler, while not really a physicist per-se, devised
> descriptions of the elliptical orbits that planets must follow.
> 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.  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.
>
> 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.

Thank you for bringing this up and explaining it so well. A few days
ago in the DeSitter thread I wrote that in SR the speed of light is
made a universal constant by the second postulate. The coordinate
systems are constructed based on that fact. Because of that there is
no way you can measure the speed of light to be anything but c without
making a mistake. I was then informed that the interpertation of SR
has been improved upon since 1905 and that what I had written no
longer applied. Further, relativity could survive even if it was
found that the speed of light wasn't exactly c. To that I responded
that if the second postulate no longer applied then they weren't
talking about Einstein's SR and should use a different name for the
theory they were describing. From there it got into a pissing contest
and I left. Care to comment?

> 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.  And if
> there is some new, more fundimental physics at a different scale,
> there's always a nobel prize, or at least several publications in it
> for anyone who can find this.
>
> In order to have a new working theory, however, you must be able to 1)
> make predictions that differ from those of the old theories and 2)
> show that those predictions match either a new experiment or a
> previously unexplained experiment.

From: J. Clarke on 21 Feb 2010 23:52
On 2/21/2010 10:24 PM, Bruce Richmond wrote:
> On Feb 21, 6:10 pm, mpalenik<markpale...(a)gmail.com> wrote:
>> On Feb 21, 4:57 pm, Ste<ste_ro...(a)hotmail.com> wrote:
>>
>>
>>
>>> If we were to extrapolate a trend from history, then physics has not
>>> yet given us a single equation which describes how the universe
>>> functions. It has given us some rules of thumb and some cumbersome
>>> approximations.
>>
>> This just further illustrates that you don't understand how physics
>> actually works. The history of physics isn't a series of blunders
>> that we've thrown out as we get better and better equations, hampered
>> by our belief in the old equations. Rather, physics at just about
>> every point in time since the renaissance has been a journey from very
>> specific to more general rules--criteria by which any new physics must
>> be constrained.
>>
>> For example, Kepler, while not really a physicist per-se, devised
>> descriptions of the elliptical orbits that planets must follow.
>> 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. 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.
>>
>> 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.
>
> Thank you for bringing this up and explaining it so well. A few days
> ago in the DeSitter thread I wrote that in SR the speed of light is
> made a universal constant by the second postulate. The coordinate
> systems are constructed based on that fact. Because of that there is
> no way you can measure the speed of light to be anything but c without
> making a mistake.

What point are you trying to support with that statement? If one
_measures_ a velocity of light other than the one that it is commonly
held to have and others replicate your result, and it is found that
light has different velocities under different circumstances then it is
not the measurement that is a mistake but you will have just thrown
relativity right out the window and they'll be seeing you in Stockholm
pretty soon.

> I was then informed that the interpertation of SR
> has been improved upon since 1905 and that what I had written no
> longer applied. Further, relativity could survive even if it was
> found that the speed of light wasn't exactly c.

Uh, by definition the velocity of light is exactly c. Grok the
concept--c is defined as "the velocity of light". Relativity makes no
statement concerning a specific value that c must have, only that it is
the same in all reference frames. It can be 2 millimeters per
millennium or forty quintillion kilometers per femtosecond and
relativity remains valid, as long as it demonstrably has that value and
only that value, within the limits of experimental error.

> To that I responded
> that if the second postulate no longer applied then they weren't
> talking about Einstein's SR and should use a different name for the
> theory they were describing. From there it got into a pissing contest
> and I left. Care to comment?

You're using phrasing that can easily lead to misunderstanding. Rather
than saying "if light has a velocity other than c", try saying "if it
can be shown that the velocity of light is different in different
reference frames", or "the velocity of light in vacuum is shown under
some circumstances to be significantly different from that which has
been measured for it in numerous experiments in the past".

<snip>
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