The perported equivalence between SR and LET however stems from an
astonishingly huge error, exemplified in this text [2]:
"... two mirrors in parallel motion, with a pulse of light bouncing
between them. In this case the motion of the mirrors actually does
diminish the frequency of bounces, relative to the stationary ether
frame, because the light must travel further between each reflection.
Thus the time intervals 'expand' (i.e., dilate). Given this time
dilation of the local moving coordinates, it's fairly obvious
that there must be a corresponding change in the effective space
coordinate (since spatial lengths are directly related to time
intervals by dx = v*dt). In other words, if an observer moves at
speed v relative to the ground, and passes over an object of length
L at rest on the ground, the length of the object as assessed by the
moving observer is affected by his measure of time. Since he is
moving at speed v, the length of the object is v*dt, where dt is the
time it takes him to traverse the length of the object – but which
"dt" will he use? Naturally if he bases his length estimate on the
measure of the time interval recorded on a ground clock, he will
have dt = L/v, so he will judge the object to be v*(L/v) = L
units in length. However, if he uses his own effective time as
indicated on his own co-moving transverse light clock, he will
have dt' = dt * (1 - v^2)^1/2, so the effective length is
v * [(L/v) * (1 - v2)^1/2] = L * (1 - v^2)^1/2. Thus, effective
length contraction (and no transverse expansion) is logically
unavoidable given the effective time dilation."
Generally accepted premisses of LET are:
- the ether is rigid
- moving time dt' dilates/expands with respect to ether time dt:
dt = dt' * gamma
- moving length dx' in direction of motion contracts wrt the ether:
dx = dx' / gamma
However, the basic reasoning exemplified in the above quoted text
implies instead of contraction of moving objects the exact contrary:
contraction of the rigid ether with respect to moving objects. In
LET (inasfar as it is not "a clever restatement" of SR), contraction
results from the motion through the ether [3], so contraction of the
ether with respect to moving objects is impossible.
References:
[1] The Twin Paradox in Special Relativity and in Lorentz Ether Theory,
http://redshift.vif.com/JournalFiles/V10NO3PDF/V10N3KHO.pdf
[2] Reflections on Relativity, 1.5 Corresponding States,
http://www.mathpages.com/rr/s1-05/1-05.htm
[3] "... assuming that the electron, deformable and compressible, is
subject to a kind of exterior constant pressure whose effect ..."
Poincaré, June 1905, see:
http://groups.google.com/group/sci.physics/msg/4e5049b2c4a76432
Correct. Your quoted example is wrong. It should be the other way.
>Since he is moving at speed v, the length of the object is v*dt, where
>dt is the time it takes him to traverse the length of the object - but
>which "dt" will he use? Naturally if he bases his length estimate on
> the measure of the time interval recorded on a ground clock, he will
>have dt = L/v, so he will judge the object to be v*(L/v) = L
That is totally wrong as you noted. The author of that claim has either
screwed up or
is.... <cough, cough>.
LET and SR perdict that a measurement of the lenght of the object will
be v*dt where dt is the measured time (clock) and v the measured speed.
The v*dt will yield L/gamma in both theories.
Who cares?, they are both ridiculous.
http://www.androcles01.pwp.blueyonder.co.uk/mmx4dummies.htm
Your summary is a bit incomplete: it omits increase of inertia with speed as
well as the fact that conventionality of simultaneity is necessary in any
interpretation. BTW, what you call "LET" is simply the earliest
interpretation of SRT, and thus it's a bit historical.
> The perported equivalence between SR and LET however stems from an
> astonishingly huge error, exemplified in this text [2]:
>
> "... two mirrors in parallel motion, with a pulse of light bouncing
> between them. In this case the motion of the mirrors actually does
> diminish the frequency of bounces, relative to the stationary ether
> frame, because the light must travel further between each reflection.
> Thus the time intervals 'expand' (i.e., dilate). Given this time
> dilation of the local moving coordinates, it's fairly obvious
> that there must be a corresponding change in the effective space
> coordinate (since spatial lengths are directly related to time
> intervals by dx = v*dt). In other words, if an observer moves at
> speed v relative to the ground, and passes over an object of length
> L at rest on the ground, the length of the object as assessed by the
> moving observer is affected by his measure of time. Since he is
> moving at speed v, the length of the object is v*dt, where dt is the
> time it takes him to traverse the length of the object - but which
> "dt" will he use? Naturally if he bases his length estimate on the
> measure of the time interval recorded on a ground clock, he will
> have dt = L/v, so he will judge the object to be v*(L/v) = L
> units in length. However, if he uses his own effective time as
> indicated on his own co-moving transverse light clock, he will
> have dt' = dt * (1 - v^2)^1/2, so the effective length is
> v * [(L/v) * (1 - v2)^1/2] = L * (1 - v^2)^1/2. Thus, effective
> length contraction (and no transverse expansion) is logically
> unavoidable given the effective time dilation."
What problem do you have with that? I think that the author of mathpages is
(as usual) correct on the math. The earth's atmosphere appears contracted to
a muon (if a muon had brains). Where do you claim that he made a mistake?
> Generally accepted premisses of LET are:
>
> - the ether is rigid
> - moving time dt' dilates/expands with respect to ether time dt:
> dt = dt' * gamma
Yes, as measured in a "stationary" system:
dt' = dt/gamma (a moving clock appears to slow down; thus a really moving
clock really slows down)
> - moving length dx' in direction of motion contracts wrt the ether:
> dx = dx' / gamma
No, not in a "stationary" system:
dx' = dx/gamma (a moving rod appears to contract; thus a really moving
rod really contracts)
> However, the basic reasoning exemplified in the above quoted text
> implies instead of contraction of moving objects the exact contrary:
> contraction of the rigid ether with respect to moving objects.
No, in SRT -no matter what your interpretation- the observations are
reciprocal. That's mentioned in your ref. 2 as well as in your ref. 3
("These transformations, ..., must form a group").
> In
> LET (inasfar as it is not "a clever restatement" of SR)
You have it upside down...
> , contraction
> results from the motion through the ether [3], so contraction of the
> ether with respect to moving objects is impossible.
The "astonishingly huge error", as you call it, is all yours.
Cheers,
Harald
:: "... However, if he uses his own effective time as
:: indicated on his own co-moving transverse light clock, he will
:: have dt' = dt * (1 - v^2)^1/2, so the effective length is
:: v * [(L/v) * (1 - v2)^1/2] = L * (1 - v^2)^1/2. Thus, effective
:: length contraction (and no transverse expansion) is logically
:: unavoidable given the effective time dilation."
:
: What problem do you have with that? I think that the author of
: mathpages is (as usual) correct on the math.
The author is discussing as possible explanations of the Michelson-
Morley experiment: "transverse expansion" versus "longitudinal
contraction" of "the material comprising Michelson's apparatus".
In order to decide this question, he makes a (consistent) reasoning
(starting from time dilation) leading to the conclusion that the
ether contracts wrt a moving object. Using this contraction of the
ether, he decides the open question in favour of "longitudinal
contraction" of Michelson's apparatus (and against "transverse
expansion").
However, the author does not notice, that contraction of the ether
wrt to the apparatus is the EXACT OPPOSITE of contraction of the
apparatus wrt the ether. The only way to get a contraction of the
ether wrt to moving objects is an expansion of the moving objects
(and their rulers) wrt the ether. See [1]. But e.g. Tom Roberts
claims (or at least claimed in January 2000) that "there is never
any sort of 'Lorentz expansion'" [2].
: The earth's atmosphere appears contracted to a muon
and the muon appears contracted to the earth's atmosphere.
However, inasfar as the atmosphere appears contracted to the muon,
the muon itself is expanded wrt the atmosphere, and inasfar the
atmosphere appears contracted, the muon is expanded.
This reciprocal contraction/expansion in SR is only possible
if we adopt Einstein's simulaneity concept, where v/c^2*x of
the time transformation is as 'real' as v*t of the x-coordinate
transformation:
x' = gamma * (x - v*t)
t' = gamma * (t - v/c^2*x)
The claim that v/c^2*x is only a convention has no more
justification than the claim that v*t is only a convention.
:: Generally accepted premisses of LET are:
::
:: - the ether is rigid
:: - moving time dt' dilates/expands with respect to ether time dt:
:: dt = dt' * gamma
:
: Yes, as measured in a "stationary" system:
:
: dt' = dt/gamma (a moving clock appears to slow down; thus a really
: moving clock really slows down)
Correct. Slowing down corresponds to EXPANSION of time intervals.
:: - moving length dx' in direction of motion contracts wrt the ether:
:: dx = dx' / gamma
:
: No, not in a "stationary" system:
:
: dx' = dx/gamma (a moving rod appears to contract; thus a really
: moving rod really contracts)
Here also you are a victim of the confusion (resp. fatal error) I'm
dealing with. According to SR, dx' = dx/gamma means contraction
of rest-frame distances wrt the moving-frame. An ether distance of
e.g. dx = 1 light-year is contracted to dx' = l LY / gamma in the
moving-frame.
However, you correctly have deduced your wrong interpretation of
dx' = dx/gamma from premisses which are assumed to be valid:
(1) In LET there is neither expansion of moving objects nor
contraction of the ether.
(2) dt' = dt/gamma
(3) dx'/dt' = v = dx/dt
From (2) and (3) you conclude dx' = dx/gamma and according to (1)
contraction of the moving object is the only valid interpretation.
So your point of view no more justifiable than the one of 'rotchm' [3]
who came to the opposite conclusion:
"Your quoted example is wrong. It should be the other way."
"The author ... has either screwed up or ..."
The existence of contradicting conclusions in a theoretical system is
a clear indication of inconsistence.
:: However, the basic reasoning exemplified in the above quoted text
:: implies instead of contraction of moving objects the exact contrary:
:: contraction of the rigid ether with respect to moving objects.
:
: No, in SRT - no matter what your interpretation - the observations are
: reciprocal. That's mentioned in your ref. 2 as well as in your ref. 3
: ("These transformations, ..., must form a group").
Do you mean by "the observations are reciprocal" that rest-frame
distances contract in the same way wrt a moving-frame as the
corresponding moving-frame distances wrt to the rest-frame? If yes,
do you suggest that this kind of reciprocity somehow follows from
the group-property of the Lorentz transformation? If yes, how?
Cheers, Wolfgang
[1] Simulation of Special Relativity by LET:
http://groups.google.com/group/sci.physics.relativity/msg/9d447bb45109a585
[2] http://groups.google.com/group/sci.math/msg/171c14a33690331b
[3] news:1169478732.9...@q2g2000cwa.googlegroups.com
I did not interpret his writing that way - instead I interpreted it as I
indicated in my next sentence.
For sure an "ether contraction" interpretation would not work and you would
be right to go against it.
> However, the author does not notice, that contraction of the ether
> wrt to the apparatus is the EXACT OPPOSITE of contraction of the
> apparatus wrt the ether. The only way to get a contraction of the
> ether wrt to moving objects is an expansion of the moving objects
> (and their rulers) wrt the ether. See [1]. But e.g. Tom Roberts
> claims (or at least claimed in January 2000) that "there is never
> any sort of 'Lorentz expansion'" [2].
See above.
> : The earth's atmosphere appears contracted to a muon
>
> and the muon appears contracted to the earth's atmosphere.
Exactly.
> However, inasfar as the atmosphere appears contracted to the muon,
> the muon itself is expanded wrt the atmosphere,
Uncontracted you should mean; and only in the rest-frame of the muon...
> and inasfar the
> atmosphere appears contracted, the muon is expanded.
Not so: moving objects appear to *contract* in SRT, while proper lengths are
unaffected.
> This reciprocal contraction/expansion in SR
See above: you must be confused...
> is only possible
> if we adopt Einstein's simulaneity concept, where v/c^2*x of
> the time transformation is as 'real' as v*t of the x-coordinate
> transformation:
>
> x' = gamma * (x - v*t)
> t' = gamma * (t - v/c^2*x)
>
> The claim that v/c^2*x is only a convention has no more
> justification than the claim that v*t is only a convention.
The convention is to declare the frame of choice to be "in rest".
> :: Generally accepted premisses of LET are:
> ::
> :: - the ether is rigid
> :: - moving time dt' dilates/expands with respect to ether time dt:
> :: dt = dt' * gamma
> :
> : Yes, as measured in a "stationary" system:
> :
> : dt' = dt/gamma (a moving clock appears to slow down; thus a really
> : moving clock really slows down)
>
> Correct. Slowing down corresponds to EXPANSION of time intervals.
>
> :: - moving length dx' in direction of motion contracts wrt the ether:
> :: dx = dx' / gamma
> :
> : No, not in a "stationary" system:
> :
> : dx' = dx/gamma (a moving rod appears to contract; thus a really
> : moving rod really contracts)
>
> Here also you are a victim of the confusion (resp. fatal error) I'm
> dealing with. According to SR, dx' = dx/gamma means contraction
> of rest-frame distances wrt the moving-frame.
dx = dx'/gamma is valid in S' only. It's an often.made mistake of
contributors to this group to mix reference frames, which implies making
transformation errors. One should not mix values of miles and and km in one
calculation.
> An ether distance of
> e.g. dx = 1 light-year is contracted to dx' = l LY / gamma in the
> moving-frame.
"ether" and "is contracted" are incompatible, just as "proper" and
"contracted" are incompatible. You could say: a rest frame distance of e.g.
dx = 1 light-year appears to be contracted to dx' = l LY / gamma in the
moving-frame.
> However, you correctly have deduced your wrong interpretation of
> dx' = dx/gamma from premisses which are assumed to be valid:
>
> (1) In LET there is neither expansion of moving objects nor
> contraction of the ether.
> (2) dt' = dt/gamma
(2) is only valid in S.
In S': dt' = dt*gamma. Just check the textbooks -they also explain why
(hint: simultaneity).
> (3) dx'/dt' = v = dx/dt
> From (2) and (3) you conclude dx' = dx/gamma
Only in S.
> and according to (1)
> contraction of the moving object is the only valid interpretation.
Indeed: "the moving object" means dx' as determined in S.
> So your point of view no more justifiable than the one of 'rotchm' [3]
> who came to the opposite conclusion:
>
> "Your quoted example is wrong. It should be the other way."
> "The author ... has either screwed up or ..."
I think that both of you misunderstand what the author of mathpages wrote.
> The existence of contradicting conclusions in a theoretical system is
> a clear indication of inconsistence.
>
> :: However, the basic reasoning exemplified in the above quoted text
> :: implies instead of contraction of moving objects the exact contrary:
> :: contraction of the rigid ether with respect to moving objects.
> :
> : No, in SRT - no matter what your interpretation - the observations are
> : reciprocal. That's mentioned in your ref. 2 as well as in your ref. 3
> : ("These transformations, ..., must form a group").
>
> Do you mean by "the observations are reciprocal" that rest-frame
> distances contract in the same way wrt a moving-frame as the
> corresponding moving-frame distances wrt to the rest-frame?
Do you mean by "distances contract", not the objects themselves but the
measures thereof? Then indeed, that's well known to be the case.
> If yes,
> do you suggest that this kind of reciprocity somehow follows from
> the group-property of the Lorentz transformation? If yes, how?
Sure - it means that the inverse transform (with v' = -v) has the same form,
so that observers in both frames measure the same effects.
Most textbooks give the derivation. For those who don't trust that or want
to see how that works in practice, I also gave an example with numbers:
See also the long recent thread where people tried to explain that to Ken
Seto ("Question on the LT and the inverse LT").
Cheers,
Harald
Harry:
::: dx' = dx/gamma (a moving rod appears to contract; thus a really
::: moving rod really contracts)
Wolfgang:
:: Here also you are a victim of the confusion (resp. fatal error) I'm
:: dealing with. According to SR, dx' = dx/gamma means contraction
:: of rest-frame distances wrt the moving frame.
Harry:
: dx = dx'/gamma is valid in S' only. It's an often made mistake ...
Should this be a con trick in order to obfuscate your error above,
or are you simply confusing dx with dx'?
Your just introduced version dx = dx'/gamma actually has the meaning
you by mistake first attributed to dx' = dx/gamma: a moving rod
contracts wrt to the rest frame.
This new version dx = dx'/gamma is valid if we assume simultaneity
in the rest frame S, i.e. dt = 0:
dx' = gamma * (dx - v*dt) --> dx' = dx * gamma
--> dx = dx' / gamma
However, the version we originally have been dealing with,
dx' = dx/gamma, implies simultaneity in S', i.e. dt' = 0:
dx = gamma * (dx' + v*dt') --> dx = dx' * gamma
--> dx' = dx / gamma
So S-simultaneity leads to contraction of S' wrt S (or expansion of S
wrt S') and S'-simultaneity to contraction of S wrt S' (or expansion
of S' wrt S).
:: An ether distance of e.g. dx = 1 light-year is contracted to
:: dx' = l LY / gamma in the moving-frame.
:
: "ether" and "is contracted" are incompatible,
and Lorentz ether theory is therefore inconsistent.
Let us assume a twin-paradox situation where one twin remains at rest
in the ether whereas the other travels with v = 0.5 c to a point 1 LY
away from the twin at rest. So an ether distance dx = l LY is passed
in dt = 2 years.
From time dilation follows that the moving twin does not need 2 years
proper time to reach the destination but only dt' = 2 Yr / gamma. So,
if the ether-distance dx from the twin at rest to the destination is
identical wrt the moving twin (i.e. dx' = dx = 1 LY) we get wrt the
moving twin a proper speed of:
v' = dx' / dt' = dx / (dt/gamma) = v * gamma.
The only way to get a moving-twin speed of v' = v is the assumption,
that the ether distance dx = 1 LY contracts by gamma wrt the moving
twin:
dx' = dx/gamma --> dx'/dt' = (dx/gamma) / (dt/gamma) = v
Time dilation is time expansion. If we combine time dilation with
length contraction, then velocity as length divided by time obviously
cannot remain invariant. Therefore we must combine time dilation of
a moving object with with length expansion of the object (equivalent
to contraction of the rest frame).
: I think that [] you misunderstand what the author of mathpages wrote.
Try again: news:ep2hvi$qli$1...@atlas.ip-plus.net
Interestingly the LET-SR confusion, we are dealing with, shows up as
a different incarnation in the article you've pointed to. There you
write:
"Similarly, the clocks will tick at 3/5 of the rate in rest, making
one tick 0.6 s of duration. Because this is determined relative to
the stationary ether or absolute space, the effects correspond to
physical reality."
http://groups.google.com/group/sci.physics.relativity/msg/9db6b5df54b79f1d
If the clock rate of a moving clock is 3/5 of the rate of rest-frame
clocks, then one moving-clock cycle does not result in 0.6 sec in the
rest frame, but in 5/3 sec. Imagine simply a transversal light clock
moving at v = 0.8 c wrt the ether.
Sorry, Wolfgang
Sorry, I didn't pay enough attention. Sure, the length dx' of the moving rod
as measured in its proper frame S' is measured as dx=dx'/gamma in rest frame
S.
> Your just introduced version dx = dx'/gamma actually has the meaning
> you by mistake first attributed to dx' = dx/gamma: a moving rod
> contracts wrt to the rest frame.
Yes.
> This new version dx = dx'/gamma is valid if we assume simultaneity
> in the rest frame S, i.e. dt = 0:
>
> dx' = gamma * (dx - v*dt) --> dx' = dx * gamma
> --> dx = dx' / gamma
>
> However, the version we originally have been dealing with,
> dx' = dx/gamma, implies simultaneity in S', i.e. dt' = 0:
>
> dx = gamma * (dx' + v*dt') --> dx = dx' * gamma
> --> dx' = dx / gamma
Yes. I thought that you did not understand that point; but obviously that's
not the issue...
> So S-simultaneity leads to contraction of S' wrt S (or expansion of S
> wrt S') and S'-simultaneity to contraction of S wrt S' (or expansion
> of S' wrt S).
That is the issue, as I explained below. In no inertial system does any
object appear to be "expanding".
> :: An ether distance of e.g. dx = 1 light-year is contracted to
> :: dx' = l LY / gamma in the moving-frame.
> :
> : "ether" and "is contracted" are incompatible,
>
> and Lorentz ether theory is therefore inconsistent.
No, there I pointed out to you what in your description is inconsistent.
> Let us assume a twin-paradox
That's really funny: the twin scheme was introduced as example with that
interpretation of SRT before it became a paradox due to reinterpretation.
> situation where one twin remains at rest
> in the ether whereas the other travels with v = 0.5 c to a point 1 LY
> away from the twin at rest. So an ether distance dx = l LY is passed
> in dt = 2 years.
>
> From time dilation follows that the moving twin does not need 2 years
> proper time to reach the destination but only dt' = 2 Yr / gamma. So,
> if the ether-distance dx from the twin at rest to the destination is
> identical wrt the moving twin (i.e. dx' = dx = 1 LY)
Of course not, why would you think so? I already pointed out to you that you
your formulation confuses appearance with hidden reality. That is not
allowed in that interpretation. In every frame one assumes to be in rest;
which implies that it is the others that are assumed to be moving - by
convention.
> we get wrt the
> moving twin a proper speed of:
>
> v' = dx' / dt' = dx / (dt/gamma) = v * gamma.
>
> The only way to get a moving-twin speed of v' = v is the assumption,
> that the ether distance dx = 1 LY contracts by gamma wrt the moving
> twin:
>
> dx' = dx/gamma --> dx'/dt' = (dx/gamma) / (dt/gamma) = v
>
> Time dilation is time expansion. If we combine time dilation with
> length contraction, then velocity as length divided by time obviously
> cannot remain invariant. Therefore we must combine time dilation of
> a moving object with with length expansion of the object (equivalent
> to contraction of the rest frame).
See above: nothing expands.
> : I think that [] you misunderstand what the author of mathpages wrote.
>
> Try again: news:ep2hvi$qli$1...@atlas.ip-plus.net
>
> Interestingly the LET-SR confusion, we are dealing with, shows up as
> a different incarnation in the article you've pointed to. There you
> write:
>
> "Similarly, the clocks will tick at 3/5 of the rate in rest, making
> one tick 0.6 s of duration. Because this is determined relative to
> the stationary ether or absolute space, the effects correspond to
> physical reality."
> http://groups.google.com/group/sci.physics.relativity/msg/9db6b5df54b79f1d
>
> If the clock rate of a moving clock is 3/5 of the rate of rest-frame
> clocks, then one moving-clock cycle does not result in 0.6 sec in the
> rest frame, but in 5/3 sec.
Hmm, it looks like you found a nasty little error. Indeed, one second
corresponds to 0.6 ticks. Note that the error is only in the intro.
> Imagine simply a transversal light clock
> moving at v = 0.8 c wrt the ether.
>
> Sorry, Wolfgang
Why? Thanks for noticing the error, I'll correct it.
And sorry that due to it, you didn't read on - for then you would not have
made the mistake above to think that moving observers should apply their
state of motion inconsistenlty. BTW, you can similarly mess up Newtonian
mechanics.
Regards,
Harald
On Jan 22, 6:36 am, "Wolfgang G. Gasser" <z...@z.lol.li> wrote:
> Adherents of LET often make statements such as "Lorentz ether theory
> does not know any paradoxes of relative motion" [1]. Even some of
> those who adhere to Special Relativity use LET in order to defend
> SR from paradoxes. They argue that LET, based only on time dilation
> and length contraction, makes the same predictions as SRT without the
> seemingly paradox SR simultaneity concept.
>
> The perported equivalence between SR and LET however stems from an
> astonishingly huge error, exemplified in this text [2]:
>
> "... two mirrors in parallel motion, with a pulse of light bouncing
> between them. In this case the motion of the mirrors actually does
> diminish the frequency of bounces, relative to the stationary ether
> frame, because the light must travel further between each reflection.
> Thus the time intervals 'expand' (i.e., dilate). Given this time
> dilation of the local moving coordinates, it's fairly obvious
> that there must be a corresponding change in the effective space
> coordinate (since spatial lengths are directly related to time
> intervals by dx = v*dt). In other words, if an observer moves at
> speed v relative to the ground, and passes over an object of length
> L at rest on the ground, the length of the object as assessed by the
> moving observer is affected by his measure of time. Since he is
> moving at speed v, the length of the object is v*dt, where dt is the
> time it takes him to traverse the length of the object - but which
No one gives a shit about LET, so feel free to find as many real or
imagined errors as you wish.
That is not a good demo.
In the MMX, the observer is always at rest wrt the apparatus.
....and you have proved again that you are a closet aetherist...
LET uses REAL contractions of length and time to explain the MMX null result.
A consequence of this is that measured OWLS will always return the value 'c'.
Einstein began with the POSTULATE that measured OWLS would be c for all
differently moving observers.
He then went on to mathematically describe the features of a universe based on
this postulate.
A consequence was that relatively moving objects would apear to be conrtracted.
I have been pointing out for months that SR is nothing but LET run backwards.
Unfortunately for both theories, there is no absolute aether and there are no
contractions, either physical or observational.
The MMX result was to be expected simply because light moves at c wrt both its
source and everything at rest in the source frame.
Note: OWLS has never been measured. OWLS from differently moving sources has
never been compared. There has never been an experiment that directly supports
either SR OR LET.
'c' is a universal constant. It is also the speed of light wrt its source.
The value of c can be determined with a TWLS experiment in vacuum, in which
case, tAB = tBA and OWLS = TWLS = c.
It's all so simple. Why try to make it difficult with a red herring?
It's better than any you've made.
>
> In the MMX, the observer is always at rest wrt the apparatus.
Yeah, so ?
"To the "stationary" observer on the left the yellow path of the "tip of the ray" as Einstein calls it (which he/she never observes) "
Can't you fucking read, dumbfuck jealous ozzie?
:: So S-simultaneity leads to contraction of S' wrt S (or expansion of S
:: wrt S') and S'-simultaneity to contraction of S wrt S' (or expansion
:: of S' wrt S).
: In no inertial system does any object appear to be "expanding".
Let us take a 6 m long (proper length) ruler moving at v = 0.8 c
wrt the ether, as described in your article:
http://groups.google.com/group/sci.physics.relativity/msg/9db6b5df54b79f1d
(See APPENDIX for my treatment/summary of your example)
You write that (under ether hypothesis) the ether-length dx = 3.6 m
of the contracted ruler corresponds to physical reality. Nevertheless,
you ascribe the proper length dx' = 6 m' to ruler. If we assume moving-
ruler simultaneity, i.e. dt' = 0, we get
dx = gamma * (dx' + v*dt') --> dx = gamma * dx'
= (5/3) * 6 m' = 10 m
This ether distance of 10 m has a very concrete meaning. Let us assume
that along the whole length of the ruler are small flash lamps next to
each other. If they fire all at the same time (S'-simultaneity) then
the distance between the first and the last flash is 10 m in the ether.
However, the flashes do not appear at the same time: at first appears
the flash from the rear, and 80/3 ns later the last flash from the
front. During these 26.666 ns the ruler moves 6.4 m, so increasing the
distance from the contracted length of 3.6 m to the expanded of 10 m.
Let us further assume that the flash lamps fire at t' = 0 in red,
at t' = 25 ns' in blue, at t' = 50 ns' again in red, and so on.
Because the next firing always occurs, when the rear end passes the
ether position where the flash from the font end fired the last time,
this represents a measurement of ether distances using the ruler
length of 6 m'. In the ether this results in an apparent light source
moving at 0.8 c and changing after each a unity of 10 m from red to
blue or inversely.
So it should be obvious that only inasfar (i.e. S'-simultaneity) as
the ruler expands from 6 m' to 10 m wrt the ether, ether distances
can contract wrt the ruler, e.g. from 6 m to 3.6 m'.
See also:
http://groups.google.com/group/sci.physics.relativity/msg/2a0f373cafaf3b3a
Your assumptions
- real contraction of moving objects wrt the ether
- no (real) contraction of ether distances wrt moving objects
- no (apparent) expansion of moving objects wrt the ether
are inconsistent with the principle of "apparent relativity" (i.e.
apparent/empirical equality of moving frames with the ether frame).
Therefore, I concluded that you and others at least sometimes confuse
"contraction of ether distances wrt moving objects" with "contraction
of these moving objects wrt to the ether". Nevertheless, the "fatal
error in LET" I'm dealing with disappears if we accept: apparent
expansion of moving objects caused by local Poincaré-simultaneity.
There is however a major empirically relevant difference between
SR and LET:
Assume a small spherical homogenous light source at the center of
a sphere with a diameter of 6 m. If the sphere is at rest in the
ether, the light intensity received from the source by the inner
surface of the sphere is obviously homogenous. Now let us assume
that the sphere moves at 0.8 c (and light propagates isotropically)
wrt the ether. Both the light source and the surrounding sphere are
contracted, resulting in analogous ellipsoids. Nevertheless, the ether
drift of -0.8 c (think about aberration) would strongly increase the
light intensity at the rear end at the expense of the front end.
(Received frequencies are the same.)
See also:
http://groups.google.com/group/sci.physics.relativity/msg/583757ad63031a21
At least in this case it is obvious, that length contraction and
time dilation are not enough to simulate the predictions of special
relativity.
Cheers, Wolfgang
________________________________________________________________________
APPENDIX:
A ruler with a rest length of 6 m passes at v = 0.8 c a rod of the
same length at rest in the ether.
The length dL' = 6 m' of the ruler is contracted by gamma in the ether:
gamma = 1/sqrt(1-v^2/c^2) = 1/sqrt(1-0.8^2) = 5/3 = 1.666
dL = dL' / gamma = 6 m' / (5/3) = 3.6 m
Time intervals dt' of clocks fixed on the ruler (x' = const) are
dilated/expanded wrt to the ether time: dt = dt' * gamma
ruler --> v = 0.8c
|--------+--------| rod
|=============================| v = 0
< - - 3.6 m - - > < - - - - - 6 m - - - - - >
< - - - - - - - - - - 10 m - - - - - - - - - - >
Clocks on both ends of the ruler are synchronized using a light signal
from the center of the ruler. In the ether system, the light signal to
the right clock (in front) needs
1.8 m / (c-v) = 1.8 m / 0.2 c = 30 ns
and passes an ether distance of 30 ns * c = 9 m. The light signal to
the left clock (in the rear) needs only
1.8 m / (c+v) ) 1.8 m / 1.8 c = 10/3 ns = 3.333 ns
and passes an ether distance of only 3.333 ns * c = 1 m. Thus in the
ether, the rear clock is ahead of the front clock by:
time_offset = 30 ns - 10/3 ns = 80/3 ns = 26.666 ns
Wrt the dilated/expanded time of the moving clocks, the time offset' is
time_offset / gamma = 26.666 ns * (3/5) = 16 ns'.
t'=0 t'=-16ns'
|--------+--------|
|=============================|
Fig. 1
t'=1ns' t'=-15ns'
|--------+--------|
|=============================|
Fig. 2
t'=10ns' t'=-6ns'
|--------+--------|
Fig. 3 |=============================|
t'=16ns' t'=0
|--------+--------|
Fig. 4 |=============================|
t'=25ns' 9ns'
|--------+--------|
Fig. 5 |=============================|
Let us define t' = 0 as the moment, the right clock of the ruler
passes the right end of the rod (Fig. 3). The left clock then
(ether simultaneity) indicates t' = 16 ns'.
The distance passed by the left clock of the ruler between Fig 1. and
Fig 4. is 10 m. During a movement of 10 meters a clock advances (proper
time) by
dt' = 10 m / 0.8 c * gamma = 10 m = (0.24 m/ns) / (5/3) = 25 ns'
In order to determine the proper speed v' as measured from the moving
ruler, we can use Fig. 4 und Fig. 5. The right end of the rod passes
at t' = 0 the right clock of the ruler, and at t' = 25 ns' the left
clock. So wrt the ruler, the right rod end moves dL' = 6 m' in
dt' = 25 ns', resulting in a proper speed of v' = dL'/dt' = 0.8 c.
In order to determine length contraction of the rod at rest wrt to
the moving ruler, we can take the left ruler end of Fig. 1 and the
right ruler end of Fig. 4, both at the same local time t' = 0. The
distance between these two ends is 10 m in the ether. And because to
these 10 m corresponds a proper length of 6 m', the 6 m long rod
contracts to 6 m' * (6 m / 10 m) = 3.6 m' wrt the ruler.
How about: http://www.users.bigpond.com/hewn/movingframe.exe
You are really demonstrating the light clock principle, not the MMX.
The MMX requires that you explain the difference in travel times between the
parallel and transverse rays for different speeds through the 'aether'.
>> In the MMX, the observer is always at rest wrt the apparatus.
>
>Yeah, so ?
>
>"To the "stationary" observer on the left the yellow path of the "tip of the ray" as Einstein calls it (which he/she never observes) "
>
>Can't you fucking read, dumbfuck jealous ozzie?
There is only one observer who is always stationary wrt the apparatus.
Why don't you demonstrate a light clock?
I didn't check in detail, but apparently you found no error.
> You write that (under ether hypothesis) the ether-length dx = 3.6 m
> of the contracted ruler corresponds to physical reality.
It just means declaring one inertial frame to be "really" at rest.
> Nevertheless,
> you ascribe the proper length dx' = 6 m' to ruler. If we assume moving-
> ruler simultaneity, i.e. dt' = 0, we get
>
> dx = gamma * (dx' + v*dt') --> dx = gamma * dx'
> = (5/3) * 6 m' = 10 m
>
> This ether distance of 10 m has a very concrete meaning.
Sure it does. In words: the proper distance of 10 m in S is measured in S'
as spanning only 6 m.
Similarly, a proper distance of 10 m in S' is measured in S as spanning only
6 m.
Thus a proper distance of 10 m is measured in the other frame as a moving
distance that appears to be *contracted* to only 6 m.
Of course, you could say that in SRT one has an "expanded" view of the
moving distance that is at any time next to one's ruler due to the apparent
contraction of the moving system. That is however only good for confusing
matters. Clearly, you managed to confuse yourself with it.
[skip more talk about expansion]
> Your assumptions
>
> - real contraction of moving objects wrt the ether
> - no (real) contraction of ether distances wrt moving objects
> - no (apparent) expansion of moving objects wrt the ether
The brackets make your above statements ambiguous, and in principle
selfcontradictory.
Instead, you were discussing the original interpretation of SRT according to
which one unknown inertial frame corresponds to the ether, so that one has
as metaphysics:
- contraction of moving objects wrt the ether
- apparent contraction of ether distances wrt a moving inertial frame (that
is assumed to be at rest, by convention)
> are inconsistent with the principle of "apparent relativity" (i.e.
> apparent/empirical equality of moving frames with the ether frame).
>
> Therefore, I concluded that you and others at least sometimes confuse
> "contraction of ether distances wrt moving objects" with "contraction
> of these moving objects wrt to the ether". Nevertheless, the "fatal
> error in LET" I'm dealing with disappears if we accept: apparent
> expansion of moving objects caused by local Poincaré-simultaneity.
That is incompatible with SRT. I must conclude that your version of SRT is
erroneous.
> There is however a major empirically relevant difference between
> SR and LET:
>
> Assume a small spherical homogenous light source at the center of
> a sphere with a diameter of 6 m. If the sphere is at rest in the
> ether, the light intensity received from the source by the inner
> surface of the sphere is obviously homogenous. Now let us assume
> that the sphere moves at 0.8 c (and light propagates isotropically)
> wrt the ether. Both the light source and the surrounding sphere are
> contracted, resulting in analogous ellipsoids. Nevertheless, the ether
> drift of -0.8 c (think about aberration) would strongly increase the
> light intensity at the rear end at the expense of the front end.
I can make no sense of that last sentence, but your reference below
clarifies it.
> (Received frequencies are the same.)
>
> See also:
> http://groups.google.com/group/sci.physics.relativity/msg/583757ad63031a21
>
> At least in this case it is obvious, that length contraction and
> time dilation are not enough to simulate the predictions of special
> relativity.
I see that also Tom Roberts tried in the past but could not get through to
you - thus I won't try more after this.
Now I copy your stuff here, and will comment only this time:
On Feb 2 2000, 9:00 am, "z@z" <z...@z.lol.li> wrote:
> : = Tom Roberts
> :: = Wolfgang G.
>
> :: But I cannot believe that the basic asymmetry in the ether has no
> :: effect at all. Isn't there a problem with the intensity of light?
If there were, then this would "kill" SRT - the math is identical.
> :: Intensity is inversely proportional to the distance square. If the
> :: ether is the medium of light, then light intensity decreases with
> :: ether distance, doesn't it?
> :
> : Yes, when measured in the ether frame. But intensity is also
> : proportional to the solid angle subtended by the detector, and
> : _that_ is not invariant. Do the computation and you will find
> : that competing effects cancel out exactly.
>
> | - - - - - - - o - - - - - - - |
> detector source of detector
> sound
>
> The sound intensity registered by the two detectors, unlike the
> measured frequency, is not independent of the speed of the medium
> (the air) wrt the system.
>
> A spherical light wave is Lorentz invariant:
>
> x^2 + y^2 + z^2 = (ct)^2 --> x'^2 + y^2 + z^2 = (ct')^2
>
> But I don't think that all segments corresponding to given solid
> angles are Lorentz invariant in the same way. We can for instance
> divide the original spherical wave into two parts separated by
> the circularly propagating wave
>
> x = 0, y^2 + z^2 = (ct)^2
>
> Thinking about stellar aberration is enough to recognize that
> this circular wave cannot be Lorentz-transformed to
>
> x' = 0, y^2 + z^2 = (ct')^2
>
> This means that if the number of photons per solid angle is
> uniform in the system at rest then it cannot be uniform in the
> moving system and vice versa.
>
> In SR it is reasonable to assume that it is always the frame
> of the source where the number of photons per solid angle is
> uniform. I doubt however that this is a reasonable assumption
> in an ether theory.
Why? it's a matter of momentum conservation. Even more, Ives *derived* SRT
based on the ether postulate plus conservation of energy and momentum.
> | - - - - - - - o - - - - - - - | -->
> detector spherical detector v
> light source
>
> Let us assume that this system moves at v = sqrt(0.99)c wrt the
> ether and that the distance between the source and each dectector
> is compressed from 10 m (restlength) to 1 m in the ether.
I can't make sense of that sentence...
> Whereas light to the right detector has to travel over 199.5 m in
> the ether, the light path to the opposite detector is only 0.5 m.
> 1 m / (1 - sqrt(0.99) = 199.5 m
> 1 m / (1 + sqrt(0.99) = 0.5 m
>
> The sound analogy would result in an intensity difference
> factor of (199.5 m / 0.5 m)^2. So the intensity registered by
> the left dectector would be (at least) 159 thousand times
> stronger than by the right detector.
Maybe you think that as measured in the rest frame (or ether frame), the
light will be emitted uniformly. Tom Roberts already told you that that is
not so. Experiments with moving gamma sources confirm that the radiation is
concentrated forward, as theory predicts: what is sent out under a straight
angle in the moving frame, is sent out nearly straight forward in the lab
frame.
> Wolfgang Gottfried G. (0:032.6)
> Cheers, Wolfgang
Good luck,
Harald
Bullshit, Albert Michelson had his buddy Edward Morley take a look.
You think he was jumping up and down?
>
> Why don't you demonstrate a light clock?
I did, I even built one. It's still working.
http://www.androcles01.pwp.blueyonder.co.uk/lightclock.gif
LEDs and NAND gates are pretty cheap, the mirrors were
more expensive. I took the capacitor out, it wasn't needed.
http://www.allaboutcircuits.com/vol_4/chpt_3/6.html
That reminds me, I've got to get the step ladder and dust it.
I put it close to the ceiling so as not to interrupt the beam,
it goes right around the walls with mirrors.
Oh well, that can wait until Spring.
: Of course, you could say that in SRT one has an "expanded" view of the
: moving distance that is at any time next to one's ruler due to the
: apparent contraction of the moving system.
My impression is that our positions have converged at least a little.
And such a convergence of different beliefs should be a goal in any
discussion. Here I'll content myself with a revised version of the
contraction/expansion part of my previous posting.
Cheers, Wolfgang
________________________________________________________________________
Let us take a 6 m long (rest length) ruler moving at v = 0.8 c in
the ether, as described in the article:
http://groups.google.com/group/sci.physics.relativity/msg/9db6b5df54b79f1d
(See APPENDIX for my treatment/summary of the example)
In Lorentz ether theory the ether-length dx = 3.6 m of the contracted
ruler corresponds to physical reality. Nevertheless, a local "proper
length" of dx' = 6 m' is ascribed to the ruler. If we assume moving-
ruler simultaneity dt' = 0, we get from the Lorentz transformation:
dx = gamma * (dx' + v*dt') --> dx = gamma * dx'
= (5/3) * 6 m' = 10 m
This ether distance of 10 m has a very concrete meaning. Let us assume
that along the whole length of the ruler are small flash lamps next to
each other. If they fire all at the same time (S'-simultaneity) then
the distance between the first and the last flash is 10 m in the ether.
However, the flashes do not appear at the same time in the ether
(S-simultaneity): at first appears the flash from the rear end, and
80/3 nano-seconds later the last flash from the front end. During
these 26.666 ns the ruler moves 6.4 m, so increasing the distance
from the contracted length of 3.6 m to the expanded of 10 m.
Let us further assume that the flash lamps fire at t' = 0 in red,
at t' = 25 ns' in blue, at t' = 50 ns' again in red, and so on.
Because the next firing always occurs, when the rear end passes the
ether position where the flash from the front end fired the last time,
this represents a measurement of ether distances using the ruler
length of 6 m'. In the ether this results in a light source apparently
moving at 0.8 c and changing after each a length unit of 10 m from
red to blue or inversely.
So it should be obvious that only inasfar (S'-simultaneity) as the
ruler expands from 6 m' to 10 m wrt the ether, ether distances can
contract wrt the ruler, e.g. from 6 m to 3.6 m'.
So in Lorentz ether theory, three basic length-unit changes can be
distinguished:
1) Contraction of objects moving wrt the ether, caused by concrete
physical effects
2) Expansion of moving objects, caused by different durations
(wrt ether simultaneity) of the movements of the different
points of the moving objects
3) Apparent contraction of the ether, resulting from the expanded
length units of moving objects.
The expanded length of a moving object is physically real also
inasfar, as it is the sum of the paths of synchronization light
signals from the center to both ends. For an apparent contraction
of ether distances wrt the WHOLE moving object, it is therefore
required that the FRONT END of the contracted object moves
inertially long enough in the ether, so that ITS distance from
the rear end can increase from L/gamma to L*gamma.
Let us assume a ruler with rest length of 2 light years moving at
v = 0.9999995 c (gamma = 1000). So the distances from the center to
each end are contracted to 0.001 LY wrt the ether. Ether distances
passed by synchronization light signals from the center to the rear
and to the front each are:
to_rear = 0.001 LY / (c + v) * c = 0.0005 LY
to_front = 0.001 LY / (c - v) * c = 1999.9995 LY
------------
2000.0000 LY
The physical expansion in the ether from the contracted 0.002 LY to
2000 LY is caused by constant MOVEMENT of the front, STARTING when
the rear after 0.0005 years receives the synchronization signal, and
ENDING 1999.999 years later when also the front receives the signal.
Such expansions by physical movement are a precondition for any
apparent contraction of ether distances wrt to moving objects.
As an accentuation of the thought experiment, let us ask what
happens if the 2 LY long ruler performs a circular movement with
an orbit of 2000 LY. In the ether, the length of the ruler is
contracted to 0.002 LY. As measured by the ruler, the orbit must
contract in the same way as local time is expanded, because
otherwise dx'/dt' does not result in v.
Thus the 2 LY' long moving ruler has to ascribe the same length
to the orbit as to itself: 2000 LY / gamma = 2 LY'. This means
concretely: under moving-ruler simultaneity', the ruler is expanded
over the whole 2000 LY of the orbit, and the front of the ruler is
next to the rear at the same time'.
________________________________________________________________________
APPENDIX:
passes the right end of the rod (Fig. 4). The left clock then
(ether simultaneity) indicates t' = 16 ns'.
The distance passed by the left clock of the ruler between Fig 1. and
Fig 5. is 10 m. During a movement of 10 meters a clock advances (local
time) by
dt' = 10 m / 0.8 c * gamma = 10 m = (0.24 m/ns) / (5/3) = 25 ns'
In order to determine the proper speed v' as measured from the moving
ruler, we can use Fig. 4 und Fig. 5. The right end of the rod passes
at t' = 0 the right clock of the ruler, and at t' = 25 ns' the left
clock. So wrt the ruler, the right rod end moves dL' = 6 m' in
dt' = 25 ns', resulting in a proper speed of v' = dL'/dt' = 0.8 c.
In order to determine length contraction of the rod at rest wrt to
the moving ruler, we can take the left ruler end of Fig. 1 and the
right ruler end of Fig. 4, both at the same local time t' = 0. The
distance between these two ends is 10 m in the ether. And because to
these 10 m corresponds a proper length of 6 m', the 6 m long rod
contracts to 6 m' * (6 m / 10 m) = 3.6 m' wrt the ruler.
_______________
-- The Lorentz transformation today plays the role the principle
-- of circular motion played in the old (pre-Keplerian) astronomy
Absolutely. LET says that if this and that contract or whatever in
accordance with Lorentz transforms you will always get c for the speed
of light. Einstein says if you always get c as the speed of light it
must be because this and that contracts or whatever in accordance with
Lorentz transforms.
Lorentz was trying to explain why we always appear to be stationary
w.r.t. the aether (interpretation of the MMX if you believe in Maxwells
aether). Starting with the aether and working towards that result.
Einstein started with the result - That we always are stationary w.r.t
the aether (interpretation of the MMX if you believe in Maxwells aether)
- which is exactly what the second postulate is describing - an observer
stationary w.r.t the aether.
As I have said before Einstein objected to the asymmetry in the
theoretical structure of Lorentz's theory and avoided it by producing a
theory with no theoretical structure.
It takes a genius to pull that sort of stunt and get away with it.
It is hardly a surprise that SR has no theoretical structure. Einstein
made a vague attempt, hinting at an aether which was such that every
observer would naturally find himself stationary w.r.t it but today,
with 'aether' being a taboo word, you would have to come up with a
theoretical structure which is consistent with the idea that the speed
at which light leaves a source is somehow solely dependent upon an
observer who at a vast distance may at some date in the far future,
observe it.
>
>Unfortunately for both theories, there is no absolute aether and there are no
>contractions, either physical or observational.
That is the daft part. That there is no aether is now generally accepted
which makes the acceptance of the Lorentz/Einstein 'aether fix'
absolutely bonkers. Self deception on a grand scale. They have spent a
100years building on a decision which makes no sense when viewed with
today's belief in 'no aether'. They say "It must have been the right
decision because we have spent 100 years building on it". I think its
called being objective :^)
Relativity did not conform to what one would expect of a physical theory
but "relativity is right" therefore what is expected of a physics theory
has been changed. There is now no quality assurance. You cannot dismiss
a theory on the grounds that it is silly.
>The MMX result was to be expected simply because light moves at c wrt both its
>source and everything at rest in the source frame.
That is certainly the most obvious interpretation of the null result and
the one which one would naturally plump for if one wasn't hung up on a
historical belief that light was a wave travelling in the aether who's
speed could not therefore be dependent upon the source. If one accepts
there is no aether it is the only logical interpretation of the MMX. You
only have a 'source' - an 'observer' and 'the space in between' if you
accept that 'the space in between' contains nothing which can influence
the speed of light you are left with a source and an observer and there
is no way the observer can control the transfer at a distance and back
through time.
>Note: OWLS has never been measured. OWLS from differently moving sources has
>never been compared. There has never been an experiment that directly supports
>either SR OR LET.
To be fair it is incredibly difficult to come up with an experiment to
distinguish. Even more difficult to come up with one which could deal
with all possible objections. Having said that it is absolutely amazing
how many people who should know better assume that such experiments are
performed every day. The underlying assumption is that if results are as
predicted by relativity they somehow disprove source dependence.
A B
If you have light travelling between A and B with a speed c w.r.t A then
the only thing which tells you whether it is SR or Ballistic theory is
which direction the light is travelling in. Mathematically that in turn
depends on which direction time is going. Mathematically 'source' and
'destination' are simply labels. Relativity seems weird but gives the
right answer because it is describing things with time going backwards
which you can't tell from the maths.
>
>'c' is a universal constant. It is also the speed of light wrt its source.
>
>The value of c can be determined with a TWLS experiment in vacuum, in which
>case, tAB = tBA and OWLS = TWLS = c.
>
>It's all so simple. Why try to make it difficult with a red herring?
--
John Kennaugh
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