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Old 13th August 2015, 05:01 PM   #41
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Just for fun:
http://rationalwiki.org/wiki/Conservapedian_relativity
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Old 13th August 2015, 07:52 PM   #42
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"An electron and a positron at rest..."

Ahem?
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Old 17th August 2015, 02:47 AM   #43
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Originally Posted by Reality Check in #39 View Post
Do you really think that SR ignores its postulate that the speed of light is c according to all inertial observers?

I only want to show that also from the alternative premise "speed of light is c only for observers in a privileged frame assumed at rest" (non-mutual) time-dilation can be derived. In general I try to understand why Special Relativity is such an efficient and useful theory despite being fundamentally flawed.

Take for instance the twin paradox:
"In 1911, Paul Langevin gave a 'striking example' by describing the story of a traveler making a trip at a Lorentz factor of y = 100 (99.995% the speed of light). The traveler remains in a projectile for one year of his time, and then reverses direction. Upon return, the traveler will find that he has aged two years, while 200 years have passed on Earth. During the trip, both the traveler and Earth keep sending signals to each other at a constant rate, which places Langevin's story among the Doppler shift versions of the twin paradox."
We can understand why such a Doppler-shift resolution actually seems to work. For the twin at rest we get the relativistic shift using these premises:
  • signals move at c (relative to himself)
  • time of travelling twin runs slower
From this we derive by "normal" logic that the following is valid for the travelling twin:

  • signals move at c relative to twin at rest
  • time of twin at rest runs faster
The SR derivation of the Doppler shift for the travelling twin however is based on these premises:

  • signals move at c (relative to himself)
  • time of twin at rest runs slower
Both derivations for the travelling twin lead (by math-magic) to the same Doppler shift. The first derivation (implying a signal-speed from c-v to c+v relative to himself) obviously violates Special Relativity. Yet also the second derivation with "normal" application of SR leads to a serious problem which becomes evident by introducing a light-clock on Earth.

The light-pulse in the clock is assumed to move orthogonally to the movement of the travelling twin. Without time dilation of this clock by Lorentz-factor 100, with respect to the travelling twin, the speed of this light-pulse would be not c but around 1.4 c (hypotenuse of right triangle with c and 0.99995 c). Thus, with respect to the travelling twin, during 1 year (proper time) before reversing direction, only 0.01 year can pass in the light clock at rest (otherwise the light-pulse would be superluminal). Also during the return trip of 1 year, only clock cycles corresponding to 0.01 years can be accomplished in the light clock at rest.

Thus we have to conclude: During reversal of direction, with respect to the travelling twin, clock-cycles corresponding to 199.98 years must be accomplished in the light-clock. During these 199.98 years, the light-pulse in the clock moves a distance of 199.98 light-years. And a light-pulse moving 199.98 light-years during an arbitrarily short time of direction-reversal quite obviously violates the very principle SR is based on.


Originally Posted by Reality Check in #39 View Post
Do you really think that scientists are so stupid that they do not test SR - including the speed of light from moving sources?
What is the experimental basis of Special Relativity? 3.3 Tests of Light Speed from Moving Sources

Please choose the experiment which according to you most convincingly contradicts what I have written. Then I can demonstrate that the experiment is either irrelevant or simply wrong.

Cheers, Wolfgang
The assumption that a theory as complex as Special Relativity is either true or false is unduly simplistic
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Old 17th August 2015, 02:03 PM   #44
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Exclamation wogoga: Please show how the "Operation of FLASH" SR test is wrong

Originally Posted by wogoga View Post
I only want to show that also from the alternative premise "speed of light is c only for observers in a privileged frame assumed at rest" (non-mutual) time-dilation can be derived.
You are wrong, wogoga. To derive time dilation you need to use all of SR. That post was silly - it starts with the relativistic Doppler formula to arrive at relativistic time dilation.

Originally Posted by wogoga View Post
In general I try to understand why Special Relativity is such an efficient and useful theory despite being fundamentally flawed.
That is a bit hypocritical, wogoga. You acknowledge that SR is a "efficient and useful theory " which is why it is not flawed! And then have the fantasy that SR is fundamentally flawed. While using SR in the post starting with the relativistic Doppler formula!

The twin paradox was resolved 80 years ago. We do not need fairy stories to resolve it.

Originally Posted by wogoga View Post
Please choose the experiment which according to you most convincingly contradicts what I have written. Then I can demonstrate that the experiment is either irrelevant or simply wrong.
So you know that you can show that any experiment in
What is the experimental basis of Special Relativity? 3.3 Tests of Light Speed from Moving Sources is wrong, wogoga.

18 August 2015 wogoga: Please show how "Operation of FLASH, a free-electron laser" is wrong.

Last edited by Reality Check; 17th August 2015 at 02:05 PM.
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Old 17th August 2015, 11:33 PM   #45
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Oddly we have two ongoing threads with one person in them who apparently has no education on Einstein, light, time, observers/their locations etc. and think they know better than actual theoreticians/academics in the field. At the same time with essentially the same againsts!!! Like fish in a barrel this is!!!!!
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Old 17th August 2015, 11:36 PM   #46
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Right here as a matter of fact: http://www.internationalskeptics.com...7#post10826567
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Old 18th August 2015, 01:19 AM   #47
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Originally Posted by fuelair View Post
That thread is relatively better.
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Old 18th August 2015, 02:08 AM   #48
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jeez, guys - keep up!

Originally Posted by Kid Eager View Post
In this thread, we have a poster who presents all maths and no logic

Over in Waterbreather's thread, we have all logic and no maths...

Both are about relativity... hmmmm

What would happen if we combined the threads?
  • a big kaboom?
  • no logic and no maths, thereby removing the thread from existence
  • illogical mathematics, that manages to prove that the speed of light is potato
  • a breakthrough in human thinking, from which we wake up and go "...but it was only a dream."
  • string, pumpkins, and those tiny cocktail umbrellas describing eccentric elliptical orbits around all the bukkits ever taken from lolrusi
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Old 18th August 2015, 06:51 AM   #49
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Originally Posted by Kid Eager View Post
jeez, guys - keep up!
Sorry, I just note the parts with nutty goodness!!!
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Old 19th August 2015, 03:31 PM   #50
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Originally Posted by wogoga in #43 View Post
Please choose the experiment which according to you most convincingly contradicts what I have written. Then I can demonstrate that the experiment is either irrelevant or simply wrong.

Originally Posted by Reality Check in #44 View Post
Please show how "Operation of FLASH, a free-electron laser" is wrong.

This experiment is irrelevant, as my arguments have nothing to do with any form of ballistic theory of light.

Quote from the summary of the experiment:
"... relativistic electron beam … generates the X-rays … speed of light emitted from the moving electrons is c+kv … observed … upper limit on k of 2.5×10−7…"
In the same way as Einstein, I assume that k is exactly zero. Nevertheless, I assume that Einstein has been fooled into believing that this is caused by the Lorentz transformation. In reality however, this is caused by ether dragging according to the inverse-square-distance law.

The refutations of this ether-drag hypothesis are as wrong as Einstein's "resolution" of the twin-paradox.

Cheers, Wolfgang
pandualism.com/d/lightclock.html
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Old 19th August 2015, 04:59 PM   #51
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Originally Posted by wogoga View Post
This experiment is irrelevant, as my arguments have nothing to do with any form of ballistic theory of light.

Quote from the summary of the experiment:
"... relativistic electron beam … generates the X-rays … speed of light emitted from the moving electrons is c+kv … observed … upper limit on k of 2.5×10−7…"
In the same way as Einstein, I assume that k is exactly zero. Nevertheless, I assume that Einstein has been fooled into believing that this is caused by the Lorentz transformation. In reality however, this is caused by ether dragging according to the inverse-square-distance law.

The refutations of this ether-drag hypothesis are as wrong as Einstein's "resolution" of the twin-paradox.

Cheers, Wolfgang
pandualism.com/d/lightclock.html
Oh really? So how does your interpretation of aether dragging reconcile the failure to accommodate stellar aberration, whilst relativity does?
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Old 19th August 2015, 07:50 PM   #52
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Question wogoga: Show that Einstein's resolution of the twin paradox is wrong

Originally Posted by wogoga View Post
This experiment is irrelevant, a...
Wrong, wogoga.
Your assertion that you "can demonstrate that the experiment is either irrelevant or simply wrong." is not supported by an link to the irrelevant ballistic theory of light.

Ignorance about special relativity does not support your assertion either, wogoga.
Einstein was not aware of the Lorentz transformation which did not exist until Poincaré 's 1905 paper published before his paper. The Lorentz transformation is derived from the postulates of SR, it is not a postulate of SR.
Einstein alone did not resolve the twin paradox.
Quote:
Starting with Paul Langevin in 1911, there have been various explanations of this paradox. These explanations "can be grouped into those that focus on the effect of different standards of simultaneity in different frames, and those that designate the acceleration [experienced by the travelling twin] as the main reason...".[2] Max von Laue argued in 1913 that since the traveling twin must be in two separate inertial frames, one on the way out and another on the way back, this frame switch is the reason for the aging difference, not the acceleration per se.[3] Explanations put forth by Albert Einstein and Max Born invoked gravitational time dilation to explain the aging as a direct effect of acceleration.[4]
Special relativity has the postulate that the speed of light is c for inertial observers. That means that SR assumes that k = 0. Scientists are not dumb and so they test to see if k is actually zero. They find that the upper limit on k is very small.
What is the experimental basis of Special Relativity? 3.3 Tests of Light Speed from Moving Sources
What makes all of these experiments irrelevant is your agreement with SR's postulate that k = 0.

In reality all ether dragging have been invalidated by empirical evidence.

Which leaves the remaining non-science as a result of ignorance of SR in the "Take for instance the twin paradox" post!

20 August 2015 wogoga: Show that Einstein's resolution of the twin paradox is wrong.
Start with citing his paper that you should have read.
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Old 21st August 2015, 03:28 PM   #53
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Originally Posted by Kid Eager in #51 View Post
Oh really? So how does your interpretation of aether dragging reconcile the failure to accommodate stellar aberration, whilst relativity does?

All aberration-based arguments against dragged ether start with the premise that light is a continuous phenomenon analogous to the propagation of sound, where propagation direction is orthogonal to the wave-front.

If the photon hypothesis already had been generally accepted then such a strange hypothesis as "length contraction" probably would not have been taken seriously in the first place. The alternative hypothesis "wave-fronts breaking-apart" is simpler and much less mind-boggling.

A photon emitted by the sun simply follows the direction of inertial movement when it adapts its speed more and more to the average velocity of the particles constituting the mass of the Earth. This complicates a little bit further the already complicated question of coherence-of-light, but it fully explains the fact that sun-light is "aberrated".

Ether dragging according to the inverse-distance-square law means that every particle in the universe drags the ether according to its mass (in the same way as every particle generates gravitational attraction). In order to calculate the movement of the ether at a given point, we simply use weighted averages of these effects (if interested see). Gravitational time dilation due to lost gravitational potential, and light bending due to gravitation show that masses are capable of influencing photon behavior.

Cheers, Wolfgang
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Old 21st August 2015, 03:38 PM   #54
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Originally Posted by wogoga View Post
Thus we have to conclude: During reversal of direction, with respect to the travelling twin, clock-cycles corresponding to 199.98 years must be accomplished in the light-clock.
Not at all, no. In fact, the SAME observation of the light-clock is made both immediately before and immediately after the reversal of direction. It's just that the observed pulse is now understood to have originated much further in the past then before. The rest of the light pulses will still be received at the appropriate intervals.
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Old 21st August 2015, 04:01 PM   #55
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Originally Posted by wogoga View Post
All aberration-based arguments against dragged ether start with the premise that light is a continuous phenomenon analogous to the propagation of sound, where propagation direction is orthogonal to the wave-front.

If the photon hypothesis already had been generally accepted then such a strange hypothesis as "length contraction" probably would not have been taken seriously in the first place. The alternative hypothesis "wave-fronts breaking-apart" is simpler and much less mind-boggling.

A photon emitted by the sun simply follows the direction of inertial movement when it adapts its speed more and more to the average velocity of the particles constituting the mass of the Earth. This complicates a little bit further the already complicated question of coherence-of-light, but it fully explains the fact that sun-light is "aberrated".

Ether dragging according to the inverse-distance-square law means that every particle in the universe drags the ether according to its mass (in the same way as every particle generates gravitational attraction). In order to calculate the movement of the ether at a given point, we simply use weighted averages of these effects (if interested see). Gravitational time dilation due to lost gravitational potential, and light bending due to gravitation show that masses are capable of influencing photon behavior.

Cheers, Wolfgang
Perhaps I'm being dense today, but you response doesn't appear to address the issue that aether dragging fails to explain observed phenomena.

In other words, it's not your perceived shortcomings with conventional theory that need further explanation, but why your pet theory fails to match observation.
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Old 22nd August 2015, 01:23 PM   #56
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Originally Posted by Reality Check in #44 View Post
To derive time dilation you need to use all of SR. That post was silly - it starts with the relativistic Doppler formula to arrive at relativistic time dilation.

As long as you do not understand the simple reasoning shown in post #33, you cannot judge #43.

And what do you consider wrong with my treatment of Langevin's twin paradox (Lorentz-factor 100; one-way travel distance of 100 LY)? Let us use two light-clocks (with light-pulse moving orthogonally to direction of relative movement) instead of twins: one clock at rest (R-clock) on Earth and the other clock (T-clock) travelling at v = 0.99995c.
  1. Distance of 100 light-year is reduced for T-clock to 1 LY during both outward and return journey.
  2. Both trips need each 100 LY / 0.99995c = 100.005 year, resp. 1 LY / 0.99995c = 1.00005 y.
  3. During 1.00005 y of one way, pulse in T-clock moves 1.00005 LY relative to T-clock.
  4. During 1.00005 y of one way, pulse in R-clock moves 1.00005 LY relative to T-clock.
  5. This 1.00005 LY path of R-clock pulse relative to T-clock is only a 0.0100005 LY path relative to R-clock.
  6. During 1.00005 y of inertial motion, 0.01 y pass in R-clock (corresponding to the 0.01 LY).
  7. During two times 1.00005 y of inertial motion, 0.02 y pass in R-clock.
  8. When both clocks meet again, 200.01 y (corresponding to light-pulse path of 200.01 LY) have passed in R-clock.
  9. During direction-change, pulse in R-clock moves 200.01 LY – 0.02 LY = 199.99 LY.
Which point do consider invalid? Or do you think that the light-clock principle itself is not consistent with SR, or that SR-simultaneity cannot be applied to the inertial motion of the travelling clock?

The contradiction is obvious:
  • For the travelling clock, time of the clock at rest is running slower by factor 100 during both inertial movements.
  • For the travelling clock, time of the clock at rest runs on average faster by factor 100 over the whole round trip.
  • Yet running faster by factor 100 is the opposite of running slower by factor 100!
  • The confusion between "slower by 100" and "slower by 0.01" as the opposite of "faster by 100" has helped SR to prosper.
Cheers, Wolfgang
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Old 22nd August 2015, 02:22 PM   #57
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Originally Posted by wogoga View Post
As long as you do not understand the simple reasoning shown in post #33, you cannot judge #43.

And what do you consider wrong with my treatment of Langevin's twin paradox (Lorentz-factor 100; one-way travel distance of 100 LY)? Let us use two light-clocks (with light-pulse moving orthogonally to direction of relative movement) instead of twins: one clock at rest (R-clock) on Earth and the other clock (T-clock) travelling at v = 0.99995c.
  1. Distance of 100 light-year is reduced for T-clock to 1 LY during both outward and return journey.
  2. Both trips need each 100 LY / 0.99995c = 100.005 year, resp. 1 LY / 0.99995c = 1.00005 y.
  3. During 1.00005 y of one way, pulse in T-clock moves 1.00005 LY relative to T-clock.
  4. During 1.00005 y of one way, pulse in R-clock moves 1.00005 LY relative to T-clock.
  5. This 1.00005 LY path of R-clock pulse relative to T-clock is only a 0.0100005 LY path relative to R-clock.
  6. During 1.00005 y of inertial motion, 0.01 y pass in R-clock (corresponding to the 0.01 LY).
  7. During two times 1.00005 y of inertial motion, 0.02 y pass in R-clock.
  8. When both clocks meet again, 200.01 y (corresponding to light-pulse path of 200.01 LY) have passed in R-clock.
  9. During direction-change, pulse in R-clock moves 200.01 LY – 0.02 LY = 199.99 LY.
Which point do consider invalid? Or do you think that the light-clock principle itself is not consistent with SR, or that SR-simultaneity cannot be applied to the inertial motion of the travelling clock?

The contradiction is obvious:
  • For the travelling clock, time of the clock at rest is running slower by factor 100 during both inertial movements.
  • For the travelling clock, time of the clock at rest runs on average faster by factor 100 over the whole round trip.
  • Yet running faster by factor 100 is the opposite of running slower by factor 100!
  • The confusion between "slower by 100" and "slower by 0.01" as the opposite of "faster by 100" has helped SR to prosper.
Cheers, Wolfgang
The answer is reincarnation.
Reincarnation resolves every paradox in SR!

Some call it synchronization. However, synchronization is just another word for reincarnation!

Observers under the action of forces are reincarnated in different inertial frames! Both observers are moving 100 times slower than the other, but one incarnation was born 100 times earlier than the other.

Einstein proved reincarnation!


If reincarnation is a trivial scientific fact, then SR is obvious logical outcome!

It is reincarnation all the way down!
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Old 23rd August 2015, 02:29 PM   #58
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Originally Posted by wogoga View Post
...snipped insults...
And what do you consider wrong with my treatment of Langevin's twin paradox (Lorentz-factor 100; one-way travel distance of 100 LY)?
I consider it wrong because it is relativity gibberish, wogoga. Making it more complex relativity gibberish does not make it better.
Twin paradox
Quote:
Starting with Paul Langevin in 1911, there have been various explanations of this paradox. These explanations "can be grouped into those that focus on the effect of different standards of simultaneity in different frames, and those that designate the acceleration [experienced by the travelling twin] as the main reason...".[2] Max von Laue argued in 1913 that since the traveling twin must be in two separate inertial frames, one on the way out and another on the way back, this frame switch is the reason for the aging difference, not the acceleration per se.[3] Explanations put forth by Albert Einstein and Max Born invoked gravitational time dilation to explain the aging as a direct effect of acceleration.[4]
You do neither. All you do is repeat Langevin's original twin paradox as if no one here can read.
Quote:
In 1911, Paul Langevin gave a "striking example" by describing the story of a traveler making a trip at a Lorentz factor of γ = 100 (99.995% the speed of light). The traveler remains in a projectile for one year of his time, and then reverses direction. Upon return, the traveler will find that he has aged two years, while 200 years have passed on Earth. During the trip, both the traveler and Earth keep sending signals to each other at a constant rate, which places Langevin's story among the Doppler shift versions of the twin paradox. The relativistic effects upon the signal rates are used to account for the different aging rates. The asymmetry that occurred because only the traveler underwent acceleration, is used to explain why there is any difference at all, because "any change of velocity, or any acceleration has an absolute meaning".[A 6]
There is no contradiction about observers measuring that each others clocks tick slower. That is what SR states !
  • For the travelling clock, the clock at rest is running slower during any inertial movements.
    This is standard SR.
  • The clock at rest after the whole round trip reads less than the travelling clock.
    This is the twin paradox - the at home twin is younger than the travelling twin!

Last edited by Reality Check; 23rd August 2015 at 02:31 PM.
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Old 23rd August 2015, 04:17 PM   #59
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Originally Posted by wogoga View Post
And what do you consider wrong with my treatment of Langevin's twin paradox (Lorentz-factor 100; one-way travel distance of 100 LY)? Let us use two light-clocks (with light-pulse moving orthogonally to direction of relative movement) instead of twins: one clock at rest (R-clock) on Earth and the other clock (T-clock) travelling at v = 0.99995c.
You're not paying attention to what each of the two observers will actually see.

The T-clock isn't close to the R-clock during the experiment; at the time it makes the transition, it's 100 light-years away. So at the time that it makes the transition, it sees a signal from the R-clock (now moving toward it at almost-c and 1 ly away) having counted 100 ticks. When does it see the next signal (marking 101 ticks) from the R-clock? What do these ticks tell it about the speed, position, and time of the R-clock?
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Old 23rd August 2015, 10:17 PM   #60
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Show your research and your math or give up. You won't win this because you are wrong.
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Old 25th August 2015, 01:20 AM   #61
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Originally Posted by wogoga View Post
Which point do consider invalid? Or do you think that the light-clock principle itself is not consistent with SR, or that SR-simultaneity cannot be applied to the inertial motion of the travelling clock?
You are only listing 2 clocks, but there are 3 clocks. The stationary Earth clock, the outbound clock t1, and the inbound clock t2. T1 and T2 are not the same clock unless you include in it's path an acceleration to change direction.

Do the math again, have Earth and T1 exchange times when T1 passes Earth, have T1 and T2 exchange times when T2 passes T1 on it's way to Earth at a point 100 LY from Earth (in Earth's inertial frame), and then have T2 exchange times with Earth when it passes Earth.

This example includes no acceleration, and the result can be easily computed. The example can also be done with a single clock that stops and turns around at the half way point.
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Old 25th August 2015, 03:03 PM   #62
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Originally Posted by fuelair in #60 View Post
Show your research and your math or give up. You won't win this because you are wrong.

Insofar as your comment represents modern "science", it shows that "science" essentially is based on faith (in authoritative orthodoxy).


Originally Posted by AdamSK in #59 View Post
You're not paying attention to what each of the two observers will actually see.

In my opinion, you try to rescue Special Relativity by confusing world-map with world-picture. Quotes from Essential Relativity, Wolfgang Rindler, 1977, World-picture and world-map:
"In relativity it is especially important to distinguish between the set of events that an observer sees at one instant and the set of events that the observer considers to have occurred at that instant. What an observer actually sees or can photograph at one instant is called a world-picture. It is a composite of events that occurred progressively earlier as they occurred farther away. For our present purposes it is irrelevant."

"The concept that plays a pervasive role in special relativity is that of the world-map. As the name implies, this may be thought of as a (3-dimensional) map of events, namely those constituting an observer’s instantaneous 3-space t = t0. It could be produced by having auxiliary observers at the coordinate lattice-points all map their immediate neighborhoods at a pre-determined time t = t0, and then joining all these local maps into a single global map."

"The world-map is generally what matters."

Originally Posted by Reality Check in #58 View Post
There is no contradiction about observers measuring that each others clocks tick slower. That is what SR states !
  • For the travelling clock, the clock at rest is running slower during any inertial movements.
    This is standard SR.
  • The clock at rest after the whole round trip reads less than the travelling clock.
    This is the twin paradox - the at home twin is younger than the travelling twin!

Your first point is correct:

  • For the travelling clock, the clock at rest is running slower during any inertial movements.
    This is standard SR.
Your second point however, despite seemingly being a common-sense conclusion from the first point, is wrong:

  • The clock at rest after the whole round trip reads less than the travelling clock.
    This is the twin paradox - the at home twin is younger than the travelling twin!
Correct within "standard SR" is the exact opposite:
  • The clock at rest after the whole round trip reads more than the travelling clock.
    This is the twin paradox - the at home twin is older than the travelling twin!
Actually your error is a salient incarnation of the Lorentz-factor confusion I mentioned at the end of post #56.

Cheers, Wolfgang
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Old 25th August 2015, 04:07 PM   #63
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Originally Posted by wogoga View Post
Your first point is correct:...
Right, wogoga.
The correct version is:
There is no contradiction about observers measuring that each others clocks tick slower. That is what SR states !
  • For the travelling clock, the clock at rest is running slower during any inertial movements.
    This is standard SR.
  • The clock at rest after the whole round trip reads more than the travelling clock.
    This is the twin paradox - the at home twin is older than the travelling twin!

You still have an ignorant treatment of the twin paradox as other posters have pointed out. Your personal confusion about the twin paradox does not mean that SR is wrong. As soon as you tried to average over two clocks when there are more in the original twin paradox, you became wrong.
  1. The at home twin has a clock for their inertial frame.
  2. The travelling twin has a clock for the inertial frame in the outbound leg. They then accelerate to turn around. That is a different inertial frame.
  3. The travelling twin has a clock for the inertial frame in the inbound leg.
The twins can then compare times on their clocks as the traveling twin passes Earth. Or the travelling twin can stop - another clock!

Last edited by Reality Check; 25th August 2015 at 04:15 PM.
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Old 25th August 2015, 05:47 PM   #64
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Originally Posted by Trebuchet View Post
I won't pretend that I fully get what was said in those paragraphs, but this one section seems weird to me.


Quote:
"For the first time, scientists have experimentally demonstrated that sound pulses can travel at velocities faster than the speed of light, c. William Robertson's team from Middle Tennessee State University also showed that the group velocity of sound waves can become infinite, and even negative. ... Although such results may at first appear to violate special relativity (Einstein's law that no material object can exceed the speed of light), the actual significance of these experiments is a little different. These types of superluminal phenomena, Robertson et al. explain, violate neither causality nor special relativity, nor do they enable information to travel faster than c. In fact, theoretical work had predicted that the superluminal speed of the group velocity of sound waves should exist. 'The key to understanding this seeming paradox is that no wave energy exceeded the speed of light,' said Robertson."[CP 6]
-----------------------------------------------------------------------------------
Some readers may be misled by this paragraph, which might be interpreted as casting doubt on relativity because the sound velocities measured are greater than the speed of light. In fact, as explained further on in the paragraph, no violation of relativity exists. There are several different methods of measuring the velocity of waves; a few of the most common are group velocity and phase velocity. In some instances, due to the nature of wave behavior and measurement techniques, measurements of both group and phase velocity can exceed c. As fascinating as that behavior is, however, no energy or information is transferred faster than c, in accordance with special relativity.
What differentiates group velocity from velocity, and why can it be said that no information transfers faster than c in those experiments when clearly, we perceive different information in them?
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Old 27th August 2015, 05:12 PM   #65
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Originally Posted by Prism View Post
I won't pretend that I fully get what was said in those paragraphs, but this one section seems weird to me.




What differentiates group velocity from velocity, and why can it be said that no information transfers faster than c in those experiments when clearly, we perceive different information in them?
Group velocity is the velocity of a pulse of light. A pulse is en envelop, etc. The formalism gets lost in mathematics. However, I think of it this way.

Group velocity is velocity of an 'image' made of light. If a film projector is used to project an image of a person on a distant screen, then that image travels on the screen at a certain distance taking an amount of time. The distance divided by time is a sort of group velocity.

Note that the velocity of the image does not necessarily correspond to the velocity of the object that that image is supposed to represent. The image can be speeded up by moving the film faster, or by editing the film by snipping out frames.

The image is physically 'real'. The image is not an 'illusion' in the strictest sense of the word. When the image moves, there are instruments that can measure the speed of the image on the screen.

One can use film to photograph The image. One can use black paper and thermometers to figure out the speed of the image. After all, when the images passes the intensity of light at that spot changes. So the black paper is heated up in a very real way. So 'images' are very real in a physical sense. The existence of an image is 'objective' in the sense of energy density.

However, the image is subjective in the sense of relativity because it does not actually carry information or even energy. It is a concentration of energy that has actually moved from a direction different from the direction that the image is moving.

Want to make a movie image go faster than light? Take a very, very long frame. Take a slide projector. It doesn't even have to be a movie director. Take the slide projector and project the image of a turtle on the screen from a very long distance. For the sake of argument, take a movie projector 10^9 km away from a screen that is 10^10 km long.

Rotate the projector at about 1 radian/second. This is about 53 degrees per second. The image will move on the screen about 10^9 km/second. The speed of light is only 3x10^5 km/second. That image of a turtle on the screen. is much faster than the speed of light.

The image of the turtle is physically real in that the light will heat the screen. The warm spot will 'travel' faster than the speed of light. However, the turtle doesn't carry any information.

The energy that makes up the optical image came from the projector to the screen. The energy of the turtle did not move in the direction of the screen. It actually moved perpendicular to the turtle.

Let us suppose that there are people near the screen who want to send messages faster than the speed of light. The image of the turtle can't carry messages. What they do to the image of the turtle at any one moment doesn't affect the image of the turtle at the next moment. If a person blocks the image in his position at a certain time, the image of the turtle merely reforms a split second later further on down the screen.


The energy from the turtle started out at the projector may 10^4 seconds ago. The energy travelled at the speed of light from the projector to the screen. It did not go faster than the speed of light. However, the image is 'moving' than the speed of light.

Once again. I won't make the mistake of calling the image an illusion. The image is a very objective concentration of energy. However, the image is not a real turtle. A real turtle CAN carry messages, although slower than the speed of light. The image was caused by an event that occurred a long time ago at the projector.

There are other scientists who will confuse the issue by saying the image is not real. Well, an image can store energy. However, the energy can't be released in any way which sends a message faster than the speed of light.

The fast moving turtle can be seen as an example of what I call 'anti-parallax'. The image is moving fast partly because of the large distance between screen and projector. It is not moving fast because energy is moving that fast.

Even a beam of light can't travel as fast as the image of the turtle. Yes, the image is ' from' light energy. However, image wasn't caused solely by the motion of the light energy. It was really caused by the rotation of the projector. The turtle can move hundreds of times faster than the sped of light


The image of the turtle doesn't violate relativity basically because it doesn't 'cause' anything. The image of the turtle is a physical object that is caused by an event very different from a real turtle.

So the 'group velocity' is really a sort of 'image velocity'. You could consider an optical image a group of photons. The group can travel faster than the photons when the photons are not causally connected.

Special relativity runs into 'paradoxes' only when the object traveling faster than the speed of light can also carry messages. If the object moves faster than the speed of light (c) an can't carry messages, it is basically just an image. There is no restriction on how fast an image can go.


I am not claiming that the research was useless. The scientists involved probably discovered something useful. Group velocity is an important concept. For example, they may be able to encode messages using this faster group velocity. They may be able to make more powerful computers using this group velocity. The concept of group velocity is very important even when it doesn't describe the sending of messages. However, they did not prove anything concerning 'relativity' one way or another.
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Old 29th August 2015, 11:46 PM   #66
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Originally Posted by Reality Check in#52 View Post
20 August 2015 wogoga: Show that Einstein's resolution of the twin paradox is wrong.
Start with citing his paper that you should have read.

Thank you for the hint.

The article Dialog about Objections against the Theory of Relativity, 1918 is quite revealing and shows that poor Einstein really had to struggle with the many serious objections against Relativity. The Critic of the dialog at least somehow represents also Einstein's own "reservations about the theory" and insecurity. For instance (first paragraph):
"We have no wish to dwell on whether this neglect [to deal with objections] was due to arrogance, or a sense of weakness, or laziness - maybe it was a particularly effective mixture of these afflictions of the soul".
Interestingly, Einstein also uses his Critic to criticize other critics (second paragraph):
"I am not so full with the status of my guild so as to make me act as a superior being with superhuman insight and certainty (…). On the contrary, I talk as a human being, since I am aware that it is not rare for criticism to originate from lack of own thoughts."
I've compiled a short text with the essence of Einstein's resolution of the twin paradox, Essence of Einstein's Resolution of the Twin Paradox, using only extracts from his original (translated) text.

Here I deal with the last paragraph of this compilation. At first, I quote Einstein, and then, I show the implications for my treatment of Langevin's twin paradox in #43 and #56.
Einstein: "According to both descriptions the clock U2 is running a certain amount behind clock U1 at the end of the observed process."
Implication: When both clocks meet again, travelling T-clock is behind R-clock, because only 2.0001 year have passed in T-clock whereas 200.01 year have passed in R-clock.
Einstein: "When relating to the coordinate system K' the behavior explains itself as follows: During the partial processes 2 and 4 [inertial motion] the clock U1, going at a velocity v, runs indeed at a slower pace than the [in K'] resting clock U2."
Implication: With respect to T-clock, R-clock runs indeed slower according to Lorentz-factor 100 during inertial motion of both forward and return trip of the journey. This results in 0.020001 year in R-clock versus 2.0001 year in T-clock.
Einstein: "However, this is more than compensated by a faster pace of U1 during partial process 3."

Process 3: "A homogenous gravitational field appears, that is directed towards the positive x-axis. Clock U1 is accelerated in the direction of the positive x-axis until it has reached the velocity v, then the gravitational field disappears again."
Implication: During direction reversal, R-clock runs faster by 199.99 year. In this way, the time delay of 2.0001 - 0.020001 = 1.98 year of T-clock with respect to R-clock during inertial motion is transformed for the whole journey into a time delay of 200.01 - 2.0001 = 198.01 year of R-clock with respect to T-clock (implying a two-time change by factor 100).

I'm genuinely flabbergasted by Einstein's continuation:
"According to the general theory of relativity, a clock will go faster the higher [weaker] the gravitational potential of the location where it is located, and during partial process 3 U2 happens to be located at a higher [weaker] gravitational potential than U1."
I had to read this several times on different days before noticing and becoming (almost) certain that already this statement stems from confusion and wishful thinking. Einstein must have confused "higher gravitational potential" with "stronger gravitational potential" or "[in K'] resting clock U2" with "clock at rest U1". If clock U1 is accelerated by a gravitational field, then U1 is located at a lower (stronger) gravitational field. And this makes clock U1 running slower, and not faster as it would be necessary to resolve the paradox.
"The calculation shows that this speeding ahead constitutes exactly twice as much as the lagging behind during the partial processes 2 and 4."
Even if instead of gravitational time dilation we had its opposite, gravitational time contraction, this statement still would be untenable, and Einstein should have written:
Under the premise that Relativity Theory is consistent, a calculation must show that this speeding ahead of clock U1 constitutes on a logarithmic scale exactly twice as much as the clock's lagging behind during the partial processes 2 and 4.
I know from personal experience that all too willingly one accepts the result of a superficial calculation or reasoning, if it agrees with one's expectation, for whatever reason.

In any case, even if I do not agree with every detail of On Einstein’s resolution of the twin clock paradox, C. S. Unnikrishnan, 2005, I have to subscribe to Unnikrishnan's conclusion:
"It is concluded that Einstein’s resolution using gravitational time dilation suffers from logical and physical flaws, and gives incorrect answers in a general setting."
Cheers, Wolfgang
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Old 30th August 2015, 03:50 PM   #67
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Originally Posted by wogoga View Post
Thank you for the hint.
I snipped some irrelevant text.
Dialog about Objections against the Theory of Relativity, 1918

Originally Posted by wogoga View Post
I'm genuinely flabbergasted by Einstein's continuation:
I am also genuinely flabbergasted , wogoga.
"According to the general theory of relativity, a clock will go faster the higher [weaker] the gravitational potential of the location where it is located, and during partial process 3 U2 happens to be located at a higher [weaker] gravitational potential than U1." is easily understood.
U2 (the travelling twin) is not on Earth. U2 is at a higher altitude (further from the Earth) than U1. That gravitational potential is "higher" and thus U2 is in a weaker gravitational potential than U1. There will be gravitational time dilation between U2 and U1.

Imagining that a "gravitational time contraction" exists does not refute Einstein's argument. So try again.

20 August 2015 wogoga: Show that Einstein's resolution of the twin paradox is wrong.

Citing a fairly obscure research article does not change physics that has withstood the test of time (almost a century). The author presents opinions about thought experiments that are not in Einstein's paper!

Cheers Reality Check
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Old 31st August 2015, 09:43 PM   #68
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Originally Posted by wogoga View Post
Insofar as your comment represents modern "science", it shows that "science" essentially is based on faith (in authoritative orthodoxy).





In my opinion, you try to rescue Special Relativity by confusing world-map with world-picture. Quotes from Essential Relativity, Wolfgang Rindler, 1977, World-picture and world-map:
"In relativity it is especially important to distinguish between the set of events that an observer sees at one instant and the set of events that the observer considers to have occurred at that instant. What an observer actually sees or can photograph at one instant is called a world-picture. It is a composite of events that occurred progressively earlier as they occurred farther away. For our present purposes it is irrelevant."

"The concept that plays a pervasive role in special relativity is that of the world-map. As the name implies, this may be thought of as a (3-dimensional) map of events, namely those constituting an observer’s instantaneous 3-space t = t0. It could be produced by having auxiliary observers at the coordinate lattice-points all map their immediate neighborhoods at a pre-determined time t = t0, and then joining all these local maps into a single global map."

"The world-map is generally what matters."




Your first point is correct:

  • For the travelling clock, the clock at rest is running slower during any inertial movements.
    This is standard SR.
Your second point however, despite seemingly being a common-sense conclusion from the first point, is wrong:

  • The clock at rest after the whole round trip reads less than the travelling clock.
    This is the twin paradox - the at home twin is younger than the travelling twin!
Correct within "standard SR" is the exact opposite:
  • The clock at rest after the whole round trip reads more than the travelling clock.
    This is the twin paradox - the at home twin is older than the travelling twin!
Actually your error is a salient incarnation of the Lorentz-factor confusion I mentioned at the end of post #56.

Cheers, Wolfgang
Although you seem fraught with lack of knowledge in this area, I must ask if you are aware that a number of interesting things and procedures developed over the last 40 + years would not function correctly (as they do) were Einstein's stuff wrong.
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Old 31st August 2015, 09:54 PM   #69
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PS: Science is based on people called scientists who actually know what we call sciences and know how it is done and for lots of it (in Physics particularly - and it's branches) by application of what is known to what is desired to be known and verifications from real experiments and real math and real checking and verifying by other real scientists who stand to gain fame and possibly fortune if they can prove it is wrong!!! Also, we have other really bright people called technologists who work very hard in related ways to apply the scientific discoveries to real material products/devices/new chemicals (etc. it's a long list) for our benefits. If you can't use it in technology, then it might not be considered so important - but, then, tech keeps right on improving all the time. This is why I cannot bring myself to give you the time of day anymore.

Have an interesting life!!!
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Old 2nd September 2015, 02:44 AM   #70
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Originally Posted by wogoga in #66 View Post
I'm genuinely flabbergasted by Einstein's continuation:
"According to the general theory of relativity, a clock will go faster the higher [weaker] the gravitational potential of the location where it is located, and during partial process 3 U2 happens to be located at a higher [weaker] gravitational potential than U1."
I had to read this several times on different days before noticing and becoming (almost) certain that already this statement stems from confusion and wishful thinking.
Originally Posted by Reality Check in #67 View Post
"According to the general theory of relativity, a clock will go faster the higher [weaker] the gravitational potential of the location where it is located, and during partial process 3 U2 happens to be located at a higher [weaker] gravitational potential than U1." is easily understood.

I had no intention to dispute the simplicity and correctness of this statement. However, this statement does not support the proposition "U1 running faster" in support of which it has been introduced. "U2 located at a higher [weaker] gravitational potential than U1" means: "U2 running faster". Thus Einstein uses "U2 running faster" in order to support a necessary premise for his resolution of the twin paradox, namely the premise "U1 running faster than U2".

I explain such a catastrophic mistake by confusion based on the belief in the validity of Relativity Theory. Yet in this case, I can even understand those who assume that Einstein used con tricks.

Once again Langevin's twin paradox with Lorentz-factor 100 and travel-distance 2 x 100 LY, with respect to the travelling clock U2:

. . . . . . . . . Travelling clock U2 . .Resting U1
. . Inertial motion . . . 2.0001 year . . 0.02 year
. . Direction reversal. . . . .0 year . 199.99 year
. . Total time. . . . . . 2.0001 year . 200.01 year


In this limit case of negligible acceleration time, direction reversal must add 199.99 year to clock U1 while clock U2 remains unchanged. And Einstein explains this "speeding ahead" of clock U1 by 199.99 year with gravitational time dilation of U1!

Cheers, Wolfgang

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Old 2nd September 2015, 03:21 AM   #71
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Originally Posted by Darwin123 View Post
This is incorrect because the speed of light is the same in all reference frames. You added the velocities linearly. However, you should have used the formula for relativistic addition of velocities.
Bwa ha ha ha! Isn't that the central principle of relativity? You'd think the OP would know that.
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Old 2nd September 2015, 03:57 AM   #72
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Originally Posted by wogoga View Post
. . . . . . . . . Travelling clock U2 . .Resting U1
. . Inertial motion . . . 2.0001 year . . 0.02 year
. . Direction reversal. . . . .0 year . 199.99 year
. . Total time. . . . . . 2.0001 year . 200.01 year


In this limit case of negligible acceleration time, direction reversal must add 199.99 year to clock U1 while clock U2 remains unchanged. And Einstein explains this "speeding ahead" of clock U1 by 199.99 year with gravitational time dilation of U1!

Cheers, Wolfgang
You've put a table where events separated by space are happening simultaneously and made comparisons between them. Such comparisons would be different depending on which inertial frame of reference you choose, making your table meaningless.
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Old 2nd September 2015, 01:47 PM   #73
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Originally Posted by wogoga View Post
I had no intention to dispute the simplicity and correctness of this statement. However, this statement does not support the proposition ...
Text in various colors do not change the physics, wogoga: Gravitational time dilation.

Fantasies about invalidating "Relativity Theory" do not change the physics, wogoga: Gravitational time dilation.

People insulting Einstein does not change the physics, wogoga: Gravitational time dilation.

Once again: Langevin's twin paradox has been resolved by people who applied vaild "Relativity Theory", wogoga.

A table of numbers in various colors does not change the physics: Twin paradox
You have a "limit case" of infinite acceleration - it takes infinite acceleration to reverse velocity on no time. That would be infinite gravitational time dilation! That is why it does not appear in Einstein's essay.

Argument by incredibility ("wow that is a big number"" but then so is the speed of light 299,792,458 m/s and it exists!) does not change the physics: Twin paradox

Dialog about Objections against the Theory of Relativity solves the general case not the specific example you are incredulous about.
Quote:
It should be kept in mind that in the left and in the right section exactly the same proceedings are described, it is just that the description on the left relates to the coordinate system K, the description on the right relates to the coordinate system K'. According to both descriptions the clock U2 is running a certain amount behind clock U1 at the end of the observed process. When relating to the coordinate system K' the behaviour explains itself as follows: During the partial processes 2 and 4 the clock U1, going at a velocity v, runs indeed at a slower pace than the resting clock U2. However, this is more than compensated by a faster pace of U1 during partial process 3. According to the general theory of relativity, a clock will go faster the higher the gravitational potential of the location where it is located, and during partial process 3 U2 happens to be located at a higher gravitational potential than U1. The calculation shows that this speeding ahead constitutes exactly twice as much as the lagging behind during the partial processes 2 and 4. This consideration completely clears up the paradox that you brought up.
The calculation is not included but this is an essay, not a scientific paper.

If you were to attempt to create a table that was valid, wogoga. then it would reflect the diagram in that essay, i.e. there would be 5 rows for each of the steps in Langevin's twin paradox. You would then do the calculation that are left out of the essay and come up with the same conclusion - the paradox is resolved.

Last edited by Reality Check; 2nd September 2015 at 02:07 PM.
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Old 2nd September 2015, 02:06 PM   #74
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Wogoga, please look up a book or an online lecture on special relativity.

Read the whole thing until you get to an explanation of the Lorentz transformation. It will look like two equations telling you how to find a transformed time-coordinate (sometimes called t') and a transformed space-coordinate (sometimes called x'). The equation tells you where to plug in BOTH x and t to find t', and where to plug in BOTH x and t to find x'. That's what Special Relativity is---it's what Einstein explained, it's what modern physicists teach and use and test.

You are doing *something* to a time coordinate t, but you are not using Special Relativity to do it. What you are doing instead is nonsense and wrong. The fact that your results are wrong is your fault, not Einstein's fault or physicists' fault.
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Old 4th September 2015, 03:22 PM   #75
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Originally Posted by ben m in #74 View Post
You are doing *something* to a time coordinate t, but you are not using Special Relativity to do it. What you are doing instead is nonsense and wrong.

Please state one concrete example of what you consider wrong. Then I will explain why you are wrong in thinking that I am wrong.

With the premises
  • U1 = resting clock or twin; U2 = travelling clock or twin
  • travel speed v (with Lorentz factor 100) in direction of x-coordinate
  • negligibly small acceleration times (or "synchronization of clocks during inertial encounter")
  • implicit use of year and LY
the Lorentz transformation for the outward trip of Langevin's twin paradox results in:

[1] x' = 100 x – 99.995 t . . [3] x = 100 x' + 99.995 t'
[2] t' = 100 t – 99.995 x . . [4] t = 100 t' + 99.995 x'


The only reasonable way to link two inertial frames F and F' is to use the event {x=0, t=0} because it transforms to event {x'=0, t'=0}. The choice of e.g. event {x=0, t = 2015 year} would transform by [1] and [2] to {-201490 LY, 201500 year} of F'. (Therefore I normally prefer to use the Lorentz transformation with coordinate-differences, e.g. for dealing with Bell's spaceship paradox).

In frame F, the event of U2 reaching the target 100 LY away, is {100 LY, 100.005 year}. This transforms to {0 LY, 1.00005 year} of F'. This result is obvious, as in F' U2 remains at x' = 0, and 1.00005 year proper time are needed to reach the reversal point.

At t' = 1.00005 year, just before changing direction (or synchronization with a clock moving in opposite direction), U1 is 1 LY (=100 LY / 100) away from U2 (in direction of the negative x'-axis). This means, U2 attributes x' = -1 LY to U1. If we transform this F'-event {-1 LY, 1.00005 year}, we get the F-event {0, 0.01 year}.

Thus, also the use of the Lorentz transformation demonstrates that in F only 0.01 year have passed, whereas 1.00005 year have passed in F'. This result agrees with both Einstein and me. So instead of the table of post #70 we get this more detailed table:

. . . . . . . . . Travelling clock U2 . .Resting U1
. . Inertial Motion 1 . .1.00005 year . . 0.01 year
. . Direction reversal. . . . .0 year . 199.99 year
. . Inertial Motion 2 . .1.00005 year . . 0.01 year
. . Total time. . . . . . 2.0001 year . 200.01 year


Cheers, Wolfgang

Also a false premise (Lorentz transformation) can lead to a correct conclusion (time dilation according to Lorentz factor)
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Old 4th September 2015, 06:31 PM   #76
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Exclamation

Originally Posted by wogoga View Post
Please state one concrete example of what you consider wrong. Then I will explain why you are wrong in thinking that I am wrong.
...
With the premises
...[*]negligibly small acceleration times (or "synchronization of clocks during inertial encounter")
...

Okay, this is wrong. The acceleration can't be negligible if it reverses the direction of the space ships motion as seen from the earth.

It the acceleration is small, then it has to act over a long time span in the rocket ship frame in order to bring the space ship back home.

If the span of time is short, then the acceleration has to be huge to bring it back home. However, a large acceleration can't be negligible.

The acceleration can' be negligible in any round trip. The act of accelerating and decelerating the rocket ship makes the acceleration with all effects significant.

The force that makes the rocket ship change direction also breaks the symmetry of the argument. When you said the acceleration was negligible, what you really meant was the force on the space ship is negligible. However, the force can't be negligible.

Every time you say that the acceleration is negligible, you are making a mistake! It is impossible for the acceleration to be negligible in a round trip!

Your challenge is a bluff. Many people have pointed out that the two rockets are in different inertial frames. I have mentioned the role of force many, many times. You have been reminded of the difference between an inertial and noninertial frame more than a hundred times.

You have NEVER addressed these claims. Not even an acknowledgement that the claims were made. You ignore people who bring up the correct answers! You accuse people of not answering you! More than a hundred times!

I predict that you will ignore my statement or try to change the subject! You will repeatedly ignore responses describing non-inertial frames for at least a hundred more posts! Maybe four thousand more posts!

However, congratulations for maintaining a thread for more than four thousand posts without once responding directly to the rebuttals that have been addressed.

I mean, four thousand posts! No coherent response from you! People are still addressing you as though you are rational!


Four thousand threads. Only twenty five participants! Maybe fifty responses per participant! Maybe one hundred correct responses! Not even one acknowledgement!

I nominate Wogoga for Relatively Light Weight Paradoxist! Or something!
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Old 6th September 2015, 02:39 PM   #77
Reality Check
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Originally Posted by wogoga View Post
Please state one concrete example of what you consider wrong. ...
"negligibly small acceleration times" is vague nonsense - any acceleration time can be considered to be "negligibly small" in the right context.

But what you really have is massive accelerations that cannot be ignored . These are the accelerations that Dialog about Objections against the Theory of Relativity considers and finds a resolution to the twin paradox in gravitational time dilation.

That the Lorentz transformation is a "false premise" reveals an abysmal ignorance of SR, wogoga, since the Lorentz transformation is not a premise !
The Lorentz transformation is a derivation of SR from its postulates that is backed up by overwhelming empirical evidence.
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Old 7th September 2015, 07:02 PM   #78
Darwin123
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Originally Posted by wogoga View Post
As long as you do not understand the simple reasoning shown in post #33, you cannot judge #43.

And what do you consider wrong with my treatment of Langevin's twin paradox (Lorentz-factor 100; one-way travel distance of 100 LY)?
Here is where you are wrong. You used an incorrect formula for time dilation. The formula that you used for time dilation is only true when the acceleration is negligible. Clearly, the acceleration is not negligible when there is a round trip.

The general solution is not accessible without calculus. However, you asked for a concrete example of how you are wrong. I think you meant 'specific' when you said concrete.


Therefore, I will present a specific case where the acceleration may be very small. The acceleration is considered a constant for the entire round trip. The acceleration may be small but it has to apply over the entire time interval in both frames. I will also ignore the orthogonal directions as you did.

Let us suppose there is a constant force being exerted on the rocket in the reference frame of the rocket. Then,

dt' = (dt) (1-[ax/c^2])/sqrt(1-(v/c)^2)

where

a = F/m.

The glossary is this:

dt': small interval of time measured by the observer in the rocket.
dt: corresponding interval of time measured by observer on earth.

F: Force on rocket
m: mass of rocket

x: distance of rocket from earth.
c: speed of light in a vacuum.
v: relative velocity between rocket and earth.
a: the dynamic acceleration of the observer.

This was derived for a one spatial dimension case where the force on the rocket is constant in time. The F in this case is the thrust of the rocket. The thrust determines the dynamic acceleration, 'a'. However, there is no thrust acting on the observer on earth. There is the asymmetry.

Note that my formula reduces to the traditional 'Lorentz time dilation formula' when F = 0. When F =0, then a = 0. In that case, the rocket can never pass the earth once more. However, the force can't be zero if the rocket passes the earth more than once.

I first got a simple version of it in the book, 'General Relativity' by Wheeler. However, he used both Greek letters and units where c=1. He also didn't really make the role of forces very clear.

Please note that the equation is not symmetrical because of the dynamic part. You can reverse the position of the observers but you can't reverse the force acting on the rocket ship.

Obviously, Wogoga wrong in the case of a rocket undergoing a constant acceleration in its own reference frame. If 'F' is not '0', then the rocket man will experience a 'speed up' of the earth bound clock at some value of 'x'. His calculation did not include the acceleration, 'a'. Instead, he stated with no justification that the 'acceleration is negligible'.

I found the formula easy to derive from the Lorentz transform and the definition of force common to both Newtonian physics and special relativity. It just took a little calculus. Perhaps you can show how I am wrong without calculus using your incredible insight.

There will be some relativity purists who would sniff that I used the concept of 'relativistic mass' which is generally frowned upon in the modern physics community. To them I say, 'Pooh'. The formula that I gave can be derived using calculus. It really doesn't matter that the mass 'm' is a tensor since I am using a one-dimensional approximation. Anyway, back to Wogoga's challenge.

You challenged us to give one concrete example of where you are wrong. You then said that you would show the poster why you were not wrong.

So here is the concrete case. I gave you a formula for the time dilation/expansion in the case of a rocket being acted on by a force constant in both magnitude and direction. The formula obviously allows for a speed up of the earth clock.

I have not insulted Wogoga in any way. I have not used any ad hominem argument. I have merely stated what the correct formula is for the case of a rocket being acted on by a constant force.


If anyone who knows relativity can see where my formula is wrong, then let his say so. Please help Wogoga out.

I gave Wogoga a very concrete reason why he is wrong. He is not using an appropriate formula. I gave him one appropriate formula, consistent with a rocket engine that is constantly running. I have shown how in this instance the acceleration has a significant affect.

Wogoga did not use the full Lorentz transformation. It is possible to handle the case of an instantaneous impulse using the full Lorentz transformation. I can also do the case for an instantaneous impulse that reverses the direction of the rocket. However, it is obvious to everybody else that the acceleration can not be negligible in this case. It is going to be huge. By restricting the force to be small but constant, I am making it simple for Wogoga. He should be able to tell me where I am wrong.

If Wogoga doesn't try to tell me why I am wrong, or changes the subject, then he was just bluffing. If he is able to tell me how my formula is inconsistent with special relativity, then he will have proven his point.

I don't think that I will get back to this thread until he addresses me one way or another. This is not an insult. I am respecting his sincerity. He said that he would answer any concrete objection to his argument. I am sure that he will follow through on his challenge.

Cheers, Wogoga!!!
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Old 9th September 2015, 07:13 AM   #79
wogoga
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Originally Posted by wogoga in #75 View Post
Please state one concrete example of what you consider wrong. Then I will explain why you are wrong in thinking that I am wrong.

With the premises
  • ...
  • negligibly small acceleration times (or "synchronization of clocks during inertial encounter")
Originally Posted by Darwin123 in #76 View Post
Okay, this is wrong. The acceleration can't be negligible if it reverses the direction of the space ships motion as seen from the earth.

It the acceleration is small, then it has to act over a long time span in the rocket ship frame in order to bring the space ship back home.

If the span of time is short, then the acceleration has to be huge to bring it back home. However, a large acceleration can't be negligible.

I must admit that what you write here seemed at first completely misguided to me, because it is possible to make the acceleration period of direction-reversal arbitrarily short in comparison with the two periods of inertial motion, by increasing the distance from resting U1 to the reversal point of travelling U2. Therefore the effect of time contraction due to acceleration can be made negligibly small compared to the effect of time dilation due to inertial motion.

Yet from Wheeler's formula of your post #78 I had to learn that my above conclusion is based on a premise, namely that time contraction due to acceleration is independent of the location where it takes place. In any case, I'll comment on Wheeler's formula.

We also have the possibility of inertial encounter mentioned by Unnikrishnan. In our case, this means that at reversal-point 100 LY away, clock U2 (v = +0.99995c) synchronizes with an identical U2 moving in opposite direction (v = -0.99995c). In this way, acceleration of U2 is fully kept out of the game.


Originally Posted by wogoga in #75 View Post
Also a false premise (Lorentz transformation) can lead to a correct conclusion (time dilation according to Lorentz factor)
Originally Posted by Reality Check in #77 View Post
That the Lorentz transformation is a "false premise" reveals an abysmal ignorance of SR, wogoga, since the Lorentz transformation is not a premise !
The Lorentz transformation is a derivation of SR from its postulates that is backed up by overwhelming empirical evidence.

The conclusion (resp. child) of one reasoning can be a premise (resp. parent) of another reasoning. Thus, insofar as we derive Lorentz-factor mass-energy-increase from the Lorentz transformation, the transformation is the premise, and mass-energy-increase is the conclusion.

Cheers, Wolfgang

Refutation of Special Relativity for Dummies (Time Dilation, Twin Paradox)

Last edited by wogoga; 9th September 2015 at 07:55 AM.
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Old 9th September 2015, 02:09 PM   #80
Reality Check
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Originally Posted by wogoga View Post
...Therefore the effect of time contraction due to acceleration can be made negligibly small compared to the effect of time dilation due to inertial motion.
Therefore we can see that you have no understanding of what you have cited or comprehension of the text that has been quoted to you, wogoga !
Dialog about Objections against the Theory of Relativity
Quote:
It should be kept in mind that in the left and in the right section exactly the same proceedings are described, it is just that the description on the left relates to the coordinate system K, the description on the right relates to the coordinate system K'. According to both descriptions the clock U2 is running a certain amount behind clock U1 at the end of the observed process. When relating to the coordinate system K' the behaviour explains itself as follows: During the partial processes 2 and 4 the clock U1, going at a velocity v, runs indeed at a slower pace than the resting clock U2. However, this is more than compensated by a faster pace of U1 during partial process 3. According to the general theory of relativity, a clock will go faster the higher the gravitational potential of the location where it is located, and during partial process 3 U2 happens to be located at a higher gravitational potential than U1. The calculation shows that this speeding ahead constitutes exactly twice as much as the lagging behind during the partial processes 2 and 4. This consideration completely clears up the paradox that you brought up.
No matter how "negligible" you imagine the acceleration to be, it is always the amount needed to account for the two other processes.
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