"The Ghost In The Machine" wrote in message
...
| In sci.physics.relativity, Jeckyl
|
| wrote
| on Wed, 30 Jan 2008 21:28:28 +1100
| :
| "Ockham" wrote in message
| k...
|
| "snapdragon31" wrote in message
|
...
| On Jan 29, 8:54 pm, Randy Poe wrote:
| On Jan 29, 8:14 pm, HW@....(Dr. Henri Wilson) wrote:
|
| According to relativists, GPS clocks GAIN 38us per day on the ground
| clock.
| That is due to two components, 45us for gravity and -7us for
relative
| speed.
|
| Accordingly, an observer (OO) in GPS orbit would see the GC LOSING
52us
| per
| day.
|
| After one year, the OO would calculate that the OC was about 19ms
ahead
| of the
| GC.
| However, the GO would calculate that his GC was only 13ms behind.
|
| What happens when the clocks are reunited?
| Who is right?
|
| Two people drive different routes from city A to
| city B. When they are reunited, one odometer reads
| 220 km and the other reads 230 km. Which one is
| right?
|
| - Randy
|
| | According to relativity, both odometer readings are wrong. They do
| | not represent the true distance of the routes travelled because of
the
| | length contraction effect.
| | According to Newton's law, both odometer readings are right.
|
| | The GPS clock paradox is a variation of the twin paradox, so no valid
| | solution.
|
| The paradox resides in the third postulate.
|
| Androcles .. we've told you .. there is no third postulate
|
| Yes there is; it's not usually expressed as a postulate, but
| it is a simple one:
|
| - If a TWLS be conducted between a source and a moving mirror,
| then the time taken (as observed by the source) of the
| light beam from source to mirror and back to source is
| exactly twice that of the time taken from source to
| mirror. In other words, t_AB = t_BA.

Not true, the reflected beam will be doppler shifted.
That's how doppler radar works.
Since c1 = lamba1 * f outbound and c2 = lambda2 * f inbound
it follows that c1 c2.

|
| There's no elegant method by which to verify this postulate
| experimentally,

Doppler radar is very elegant. It falsifies the postulate which is why
there is no elegant way to verify it.


|
| Besides, as Ockham should well know by now, if the light
| goes c+v in one direction and c-v in the other,

That's just plain silly, the car doesn't change direction.
the radar goes at 0+c leaving the gun and returns at v-c.

| the average
| speed thereby is less than c because of a variant of the
| "headwind/tailwind" effect; the MMX was designed to measure
| that effect (and failed to show any variance).

Non sequitur, GPS doesn't use average speed.

| Also, various other measurable effects are well-documented.

Non sequitur, Ptolemy's epicycles are well-documented (and wrong).


| For example, SR postulates changes in wavelength and frequency;
| Newton merely postulates changes in frequency.

Nope. Newton postulates NO change in frequency.
c1 = lambda1 * f
c2 = lambda2 * f



| It is all paradoxical, to be sure -- but there's no real contradiction.

Assertion carries no weight.



|
|
| 'the "time" required by light to travel from A to B equals
| the "time" it requires to travel from B to A' -- Albert Einstein
|
| The time for a signal to get from the satellite to the receiver
| does not equal the time for an uplink because the satellite has
| moved, obviously.
|
| Indeed .. SR and Einstein agrees with that.

Nope. In SR the uplink time is the same as the signal time.


| Time from A to B for light is
| only the same as the time from B to A when A and B both at rest in some
| frame of reference (ie they are not moving relative to each other)
|
|
| B does not have to be at rest. Of course the actual time
| at which the ray of light impacts B (and the position
| of B at the point of impact) might be a little hard to
| specify unless one has an alternate "infinite speed"
| particle, which is currently (and probably forever will
| be) impossible.

You have elegant way of verifying it, but there are many
elegant ways to falsify it, of which doppler is the easiest.
Bigotry is not elegant.