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Length contraction and pressure


ravell

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On 24.06.2018 at 2:25 PM, swansont said:

Where is your promised explanation of these effects using Newtonian physics?

 

The tick time of the light clock at rest, is given by the formula To = 2D /c, where D is the length of the clock tube , and c is the speed of the photon timing the clock in the tube (speed of light).

 

The tick time of the light clock in motion at the speed v, is given by the formula T = L /c, where L is the length of optical path of the timing photon, which for the tube transverse to the clock movement  is L = 2 [(v * T /2)^2 + D^2]^0,5

Thus, the tick time of the light clock in motion is:

 

T = L /c = 1 /c * 2 [(v * T  2)^2 + D^2]^0,5

 

Solving this equation with respect to T, we get:

 

T = 2D/(c^2-v^2)^0,5 = (2D/c)/ (1-v^2/c^2)^0,5 = To/(1-v^2/c^2)^0,5

Thus, the Newtonian physics clearly shows that the light clock moving, for example, at the speed v = 0.866 c, will run two times slower than the clock at rest (on the Earth), and as shown above, this has nothing to do with theory of relativity.

 

 

 

 

 

 

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1 hour ago, ravell said:

Thus, the Newtonian physics clearly shows that the light clock moving, for example, at the speed v = 0.866 c, will run two times slower than the clock at rest (on the Earth), and as shown above, this has nothing to do with theory of relativity.

Of course it has. You are supposing that c is the same for the observer in the spaceship and for the observer on earth. But that is not according to Newton. According to classical mechanics, you must take into account that the velocity of light that the earth observer sees is the vector sum of the speed of the light between the mirrors plus the velocity of the spaceship. If you do the calculation you would see that for the earth observer the clock still has the same ticking rate as his own local clock.

Edited by Eise
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1 hour ago, ravell said:

The tick time of the light clock in motion at the speed v, is given by the formula T = L /c, where L is the length of optical path of the timing photon, which for the tube transverse to the clock movement  is L = 2 [(v * T /2)^2 + D^2]^0,5

If this were true, you would be able to measure your (absolute) speed. We know you can't.

The reason is that L = D in the frame of the light clock, whatever its state of motion. And, in a purely Newtonian universe, L always equals D.

You are implicitly assuming one of the postulates of relativity (that c is independent of the motion of the source). And, therefore, your solution is relativistic.

But note that L > D as seen by an external ("stationary") observer. The rate at which the light clock ticks doesn't change for the observers moving with it.

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On 28.06.2018 at 8:24 PM, Strange said:

If this were true, you would be able to measure your (absolute) speed. We know you can't.

Can you explain how it would be possible or impossible?

 

Quote

The reason is that L = D in the frame of the light clock, whatever its state of motion. And, in a purely Newtonian universe, L always equals D

This is not true!  Could you present here a picture of the propagation of a light wave  in a moving light clock, which would prove that the length (L)  of optical path for photon  is always equal to the length (D) of the clock tube, regardless of the clock's movement?

 

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You are implicitly assuming one of the postulates of relativity (that c is independent of the motion of the source). And, therefore, your solution is relativistic.

Light is an electromagnetic wave the same as radio waves, and its speed of propagation depends only on the environment  in which it spreads, and does not depend on the motion of the generator of these waves. This has nothing to do with relativity!

There is a full analogy to the propagation of waves in water (or air), where the speed of wave propagation in a lake does not depend on the speed of the boat that makes these waves (let's skip the Doppler effect  here).

 

Quote

But note that L > D as seen by an external ("stationary") observer. The rate at which the light clock ticks doesn't change for the observers moving with it.

It will not change? Regarding what reference clock he will find out?

If the observer in motion will compare the tics of his light clock with the tics of an external reference clock, for example a pulsar, he will be absolutely watching the slowdown of his clock.

Clocks at the ISS station orbiting at a speed of 7,7 km/s, are delayed about  24 microseconds a day, in relation to the clocks on Earth and it is observed on this station.

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2 hours ago, ravell said:

Could you present here a picture of the propagation of a light wave  in a moving light clock, which would prove that the length (L)  of optical path for photon  is always equal to the length (D) of the clock tube, regardless of the clock's movement?

It is up to you to show, without using the invariance the speed light, that your alternative hypothesis is correct.

2 hours ago, ravell said:

Light is an electromagnetic wave the same as radio waves, and its speed of propagation depends only on the environment  in which it spreads, and does not depend on the motion of the generator of these waves. This has nothing to do with relativity!

Er, that IS one of the postulates on which relativity is based. If you assume that, then you will reach the same conclusions s relativity. As, indeed, you seem to be doing.

2 hours ago, ravell said:

It will not change?

Of course not. You are moving at near the speed of light (relative to something); does your watch run slow? Of course not.

2 hours ago, ravell said:

If the observer in motion will compare the tics of his light clock with the tics of an external reference clock, for example a pulsar, he will be absolutely watching the slowdown of his clock.

No, he will see the pulsar (which is moving relative to him) going slower than would someone stationary relative to the pulsar.

2 hours ago, ravell said:

Clocks at the ISS station orbiting at a speed of 7,7 km/s, are delayed about  24 microseconds a day, in relation to the clocks on Earth and it is observed on this station.

There is also a gravitational difference, but if we were only to consider relative speed, then the ISS would see Earth clocks running slow. (I haven't worked out what effect gravity has one this.)

 

You can make all sorts of counterfactual claims about what you believe will happen in these scenarios, but theory and experiment shows you to be wrong. 

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2 hours ago, ravell said:

Light is an electromagnetic wave the same as radio waves, and its speed of propagation depends only on the environment  in which it spreads, and does not depend on the motion of the generator of these waves. This has nothing to do with relativity!

Wow!!! It never ceases to amaze me that many  who claim Einstein was wrong and SR/GR invalid, can not even get the basics right. While I am certainly out of my depth in explaining this in minute detail, I am aware that the invariant finite nature of "c"  is the prime edict of SR. These same rather egotistical individuals also invariably ask for "proof" or to "prove it", when [1] the onus of "proof" is on them, and [2] Scientific theories are not concerned with proof or reality as such. :rolleyes:

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If the observer in motion will compare the tics of his light clock with the tics of an external reference clock, for example a pulsar, he will be absolutely watching the slowdown of his clock.

No, no, no! Please get yourself informed of the theory you are trying to invalidate. Another edict of relativity, is that any individual always sees his or her own clocks, both mechanical and biological, to be always running as per normal at one second per second. It is only when he views another clock in another frame of reference, that is residing in a different gravity well, or going at speed, that he will observe time dilation and length contraction in that frame..

Oh the pain of it all!!! :D

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4 hours ago, ravell said:

Light is an electromagnetic wave the same as radio waves, and its speed of propagation depends only on the environment  in which it spreads, and does not depend on the motion of the generator of these waves. This has nothing to do with relativity!

 

There is a full analogy to the propagation of waves in water (or air), where the speed of wave propagation in a lake does not depend on the speed of the boat that makes these waves (let's skip the Doppler effect  here).

There is not a direct analogy between electromagnetic waves (in vacuum) to water or air waves.   Water and air waves have a fixed speed with respect to the medium.  While the speed of the waves relative to the water are not dependent of the velocity of the boat making the waves, the speed of the waves relative to the boat as measured from the boat does.  A boat could determine its speed relative to the water by measuring the speed the waves it produces moves relative to it.

With electromagnetic waves, the speed of the waves relative to the source is always c as measured by the source, and it is always c relative to the receiver as measured by the receiver regardless of the relative velocity between source and receiver.  A light source cannot determine its speed by measuring the speed of the light waves is produces relative to itself.

4 hours ago, ravell said:

If the observer in motion will compare the tics of his light clock with the tics of an external reference clock, for example a pulsar, he will be absolutely watching the slowdown of his clock.

No, he will not If he were approaching the pulsar he would measure those ticks at a rate of sqrt((1+v/c)/(1+v/c) and if he is receding from it he would measure the ticks at a rate of sqrt((1-v/c/(1+v/c)).     Here v is the relative speed between himself and the Pulsar. It doesn't matter if he considers the plsar as approaching him or himself and the pulsar stationary.

A part of this is is account for by the fact that when approaching the distance between the pulsar and observer is decreasing and when receding it is increasing. After you factor this out, you will be left with the time dilation equation and the result that they will measure the pulsar ticks as being slow when compared to his own clock.  This is also what he will measure if were to flying past the pulsar at the moment of closest approach (when they are neither approaching or receding from each other). This is known as the transverse Doppler shift effect.

4 hours ago, ravell said:

Clocks at the ISS station orbiting at a speed of 7,7 km/s, are delayed about  24 microseconds a day, in relation to the clocks on Earth and it is observed on this station.

Clocks in the ISS are traveling in circular orbit and thus are not in inertial motion (they are in an accelerated frame.)  When working from accelerated frames, you can't just take the relative speed into account, but also the acceleration, which in this case always points towards the Earth.  A clock which is in an inertial frame, measuring a clock that is accelerating does not have to consider the acceleration, just the speed.   As long as both frames remain inertial, they will always measure the clock in the other frame as ticking slow if there is relative motion between them. 

 

 

 

 

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6 hours ago, Janus said:

Clocks in the ISS are traveling in circular orbit and thus are not in inertial motion (they are in an accelerated frame.) 

While I understand what you are trying to say, I think the above is a little sloppy. The ISS travels on a geodesic in spacetime (it does not fire thrusters at any time), so it is in inertial motion, because an on-board accelerometer will always read exactly zero. 

The thing is just that spacetime between the ISS and the earth-bound observer is not Minkowski - hence relative motion is not the only factor that needs to be accounted for when calculating the time dilation between the two clocks, because the relationship between these frames is more complicated than just a simple hyperbolic rotation. However, it turns out - due to the symmetries of Schwarzschild spacetime - that the SR and GR effects simply add up to give the total time dilation in this case (note that this is not true in the general case).

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16 hours ago, ravell said:

 Light is an electromagnetic wave the same as radio waves, and its speed of propagation depends only on the environment  in which it spreads, and does not depend on the motion of the generator of these waves. This has nothing to do with relativity!

On the contrary, it has everything to do with relativity. It was the application of this principle to kinematics that led Einstein to derive relativity. Newtonian physics is not Lorentz invariant. Electrodynamics is. 

Quote

Clocks at the ISS station orbiting at a speed of 7,7 km/s, are delayed about  24 microseconds a day, in relation to the clocks on Earth and it is observed on this station.

 

Which is a combination of gravitational and kinematic time dilation, as predicted by relativity.

12 hours ago, Janus said:

 Clocks in the ISS are traveling in circular orbit and thus are not in inertial motion (they are in an accelerated frame.)  When working from accelerated frames, you can't just take the relative speed into account, but also the acceleration, which in this case always points towards the Earth.  A clock which is in an inertial frame, measuring a clock that is accelerating does not have to consider the acceleration, just the speed.   As long as both frames remain inertial, they will always measure the clock in the other frame as ticking slow if there is relative motion between them. 

One of the followups to the Pound-Rebka experiment looked at time dilation in a centrifuge. The fractional frequency shift is given by 

(R12 - R22)w2/2c2

"One can treat the acceleration as an effective gravitational field and calculate the difference in potential between the source and absorber, or one can obtain the same answer using the time dilatation of special relativity"

IOW, the effects do not add. That's not the right approach.  

 

MEASUREMENT OF THE RED SHIFT IN AN ACCELERATED SYSTEM USING THE MOSSBAUER EFFECT IN Fe57

H. J. Hay, J. P. Schiffer,*T. E. Cranshaw, and P. A. Egelstaff

PRL, Feb 15, 1960

 

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2 hours ago, swansont said:

On the contrary, it has everything to do with relativity. It was the application of this principle to kinematics that led Einstein to derive relativity. Newtonian physics is not Lorentz invariant. Electrodynamics is. 

Which is a combination of gravitational and kinematic time dilation, as predicted by relativity.

One of the followups to the Pound-Rebka experiment looked at time dilation in a centrifuge. The fractional frequency shift is given by 

(R12 - R22)w2/2c2

"One can treat the acceleration as an effective gravitational field and calculate the difference in potential between the source and absorber, or one can obtain the same answer using the time dilatation of special relativity"

IOW, the effects do not add. That's not the right approach.  

 

MEASUREMENT OF THE RED SHIFT IN AN ACCELERATED SYSTEM USING THE MOSSBAUER EFFECT IN Fe57

H. J. Hay, J. P. Schiffer,*T. E. Cranshaw, and P. A. Egelstaff

PRL, Feb 15, 1960

 

I did say that an observer who, is in an inertial frame, measuring a clock that is accelerating does not have to consider the acceleration, just the speed.

This is what the centrifuge experiment shows. It is measuring the time dilation for an accelerating clock as measured from an inertial frame (the lab frame). In this case, the accelerating clock is measured as running slow at a rate that only depends on the speed of the clock.

The point I was addressing was that which is measured from within the accelerating frame.  If you were riding along with the clock in the centrifuge, and measuring the tick rate of a clock at the axis, you would measure the axis clock as running fast.  In the rotating frame of the centrifuge, the relative velocity between the two clocks is zero.  There is a potential difference between the two clocks due to the centripetal acceleration which causes the the observer on the end of the arm to measure the clock at the axis as running faster.  The magnitude of the tick rate difference will be the same as the time dilation measured from the lab frame.

This is different from the case where both observers are in inertial frames with a relative velocity with respect to each other, where they both would measure the clocks in the other frame as ticking slow compared to their own.

ravell was trying to argue ( By using the ISS example), that since the clock at the end of a centrifuge would agree with the lab that it was accumulating time at a slower rate than the clock in the lab frame, that this supported his argument that a spaceship moving at a constant velocity would measure a pulsar's clock as running fast.   He was equating apples to oranges in terms of measurements made from inertial frames vs. those made from non-inertial frames under the rules of SR.

 

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17 hours ago, Janus said:

No, he will not If he were approaching the pulsar he would measure those ticks at a rate of sqrt((1+v/c)/(1+v/c) and if he is receding from it he would measure the ticks at a rate of sqrt((1-v/c/(1+v/c)).     Here v is the relative speed between himself and the Pulsar. It doesn't matter if he considers the plsar as approaching him or himself and the pulsar stationary.

A part of this is is account for by the fact that when approaching the distance between the pulsar and observer is decreasing and when receding it is increasing. After you factor this out, you will be left with the time dilation equation and the result that they will measure the pulsar ticks as being slow when compared to his own clock.  This is also what he will measure if were to flying past the pulsar at the moment of closest approach (when they are neither approaching or receding from each other). This is known as the transverse Doppler shift effect.

For ease, we are considering here the case in which our light clock moves perpendicular to the pulsar light line. It can therefore be assumed that it moves around the pulsar in an orbit with a radius R equal to, for example, the distance of the pulsar from the Earth. Therefore, there is no Doppler effect  here. The light clock in spacecraft  moving at the speed v = 0.866c, will have a tick twice as slow as on Earth at the moment of takeoff. Pulsar observed from Earth generates 100 flashes per minute.

 If any theory claims that the observer on the spacecraft will see less pulsar flashes per minute of the local clock  than the observer on Earth, then the conclusion can only be such that this theory does not apply to our reality.

5 hours ago, swansont said:

      "Clocks at the ISS station orbiting at a speed of 7,7 km/s, are delayed about  24 microseconds a day, in relation to the clocks on Earth and it is observed on this station."

  Which is a combination of gravitational and kinematic time dilation, as predicted by relativity.

The ISS station orbits  416 km above the Earth. Kinematic time dilation is -28,23 microseconds, and gravitational time dilation is  3,69 microseconds. Total  -24,54 microseconds.
Both of these values also result from Newtonian physics.
The exact calculations in this area are available in the program on the link:

https://www.dropbox.com/s/9ljwu5wwsi0v9up/VerificationTheoryRelativity.xlsx?dl=0

 (To download the Excel file from Dropbox, you do not need to be logged in. You only have to choose the options: download> download directly> enable editing).

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Your still looking at the pulses vs time relations incorrectly. If time is affected then so too is the pulse rate. As long as you ignore pulse rate you will keep getting the wrong conclusions. It isn't the number of pulses but the pulse rate that is affected. Try to wrap your head around the difference.

Here start with a digital signal for simplicity. The Pulse rate itself will measure the differences between the rising and falling edges of the signal. This is done for the error corrections of GPS satellites.

to Quote.

"To measure the delay, the receiver compares the bit sequence received from the satellite with an internally generated version. By comparing the rising and trailing edges of the bit transitions, modern electronics can measure signal offset to within about one percent of a bit pulse width"

https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_Positioning_System

Now connect the dots to gravitational redshift.

https://en.wikipedia.org/wiki/Gravitational_redshift

Frequency is a rate.... the pulses change RATE. Here is three frequency formulas hopefully you will see the differences.

[latex] f=\frac{1}{t}[/latex]

[latex]f=\frac{V}{\lambda}[/latex] V is the wave velocity...

[latex]f=\frac{c}{\lambda}[/latex]

Also consider this detail, there is 3 other Very knowledgeable posters in GR responding in this thread if I am wrong they will happily and correctly point out my mistakes.

 

Edited by Mordred
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6 minutes ago, ravell said:

The ISS station orbits  416 km above the Earth. Kinematic time dilation is -28,23 microseconds, and gravitational time dilation is  3,69 microseconds. Total  -24,54 microseconds.
Both of these values also result from Newtonian physics.
The exact calculations in this area are available in the program on the link:

 

https://www.dropbox.com/s/9ljwu5wwsi0v9up/VerificationTheoryRelativity.xlsx?dl=0

 

 (To download the Excel file from Dropbox, you do not need to be logged in. You only have to choose the options: download> download directly> enable editing).

 

Your calculations have already been shown to be flawed (invariant c is not Newtionian), and the rules say you have to present your material here.

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1 hour ago, ravell said:

For ease, we are considering here the case in which our light clock moves perpendicular to the pulsar light line. It can therefore be assumed that it moves around the pulsar in an orbit with a radius R equal to, for example, the distance of the pulsar from the Earth. Therefore, there is no Doppler effect  here. The light clock in spacecraft  moving at the speed v = 0.866c, will have a tick twice as slow as on Earth at the moment of takeoff. Pulsar observed from Earth generates 100 flashes per minute.

Then the spacecraft is in a non-inertial frame.  For the sake of simplicity, we will ignore the gravitational effect of the pulsar.  Thus in order to "orbit" the pulsar, the spaceship would have to be constantly thrusting towards the pulsar and thus has a constant centripetal acceleration towards the pulsar. Under SR, the rules for treating observations from a non-inertial frame are different from those for treating observations made from an inertial frame.  A spaceship traveling in a straight line at 0.866 c relative to the pulsar will measure the pulsar as ticking at a slower rate.  

 

1 hour ago, ravell said:

If any theory claims that the observer on the spacecraft will see less pulsar flashes per minute of the local clock  than the observer on Earth, then the conclusion can only be such that this theory does not apply to our reality.

SR predicts that that observer circling the pulsar will measure the pulsar rate as being fast, but one traveling in inertial frame (straight line, no acceleration)  at the same relative speed will measure it as being slow.  Both these conclusions come from the consistent application of SR to both scenarios.

This is because you have to treat non-inertial observers differently than inertial observers. The predictions of SR are perfectly in line with reality.

Your personal inability to grasp or refusal to accept this is not an argument against the validity of SR as a theory nor the predictions it makes.

1 hour ago, ravell said:

The ISS station orbits  416 km above the Earth. Kinematic time dilation is -28,23 microseconds, and gravitational time dilation is  3,69 microseconds. Total  -24,54 microseconds.
Both of these values also result from Newtonian physics.
The exact calculations in this area are available in the program on the link:

This actually argues against your contention.    The Earth also orbits the Sun at a relative velocity of ~30 km per sec.   For part of The ISS orbit its orbital velocity relative to the Earth is added to this, and for part of it the ISS orbital velocity is subtracted.  Thus for part of the time it is moving slower than the Earth relative to the Sun and part of the time it is moving faster.  According to your argument, the ISS clock should spend ~1/2 of its time running slower than the Earth clock and ~1/2 of its time running faster.  It does not do so.

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2 hours ago, ravell said:

Both of these values also result from Newtonian physics.

There is no gravitational time dilation in Newtonian physics.

2 hours ago, ravell said:

(To download the Excel file from Dropbox, you do not need to be logged in. You only have to choose the options: download> download directly> enable editing).

I would strongly advice people NOT to download Excel (or Word) files from unknown sources. This is a very serious security risk.

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  • 4 weeks later...
On 30.06.2018 at 9:46 PM, Strange said:

There is no gravitational time dilation in Newtonian physics.

I would strongly advice people NOT to download Excel (or Word) files from unknown sources. This is a very serious security risk.

 

Gravitational time dilation between two levels of different gravitation, is a phenomenon resulting from classical physics (Newtonian physics) and is always equal to the delay that would have a light clock, moving at the speed that the clock would gain during a free fall from a level with lower gravitation to level with greater gravitation.

This is clearly presented in the previously given VETER program available on the link:

https://www.dropbox.com/s/9ljwu5wwsi0v9up/VerificationTheoryRelativity.xlsx?dl=0

 

This program is available on the internet for several years and has many users. Currently, there is  version  2.0+++.

 

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24 minutes ago, ravell said:

This is clearly presented in the previously given VETER program available on the link:

The rules require you to present your argument, and the supporting math, here on the forum. (Reported)

24 minutes ago, ravell said:

This program is available on the internet for several years and has many users.

The same can be said about much malware. I certainly wouldn't trust a spreadsheet from an unknown source. 

Edited by Strange
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3 hours ago, ravell said:

Gravitational time dilation between two levels of different gravitation, is a phenomenon resulting from classical physics (Newtonian physics)

Classical physics yes, Newtonian physics no. Like Strange has already pointed out, Newtonian physics operates under the assumption that there is an absolute time, so obviously there cannot be time dilation of any kind. Gravitational time dilation is purely a GR effect.

3 hours ago, ravell said:

is always equal to the delay that would have a light clock, moving at the speed that the clock would gain during a free fall from a level with lower gravitation to level with greater gravitation.

This is not true in general. Gravitational time dilation arises from the g{tt} component of the metric tensor, which, in the vicinity of a source of gravity, is a non-constant function. Only if the spacetime in question is both spherically symmetric and stationary, is there a correlation between gravitational time dilation and escape/free-fall velocity. Schwarzschild spacetime is one example for this, but it is not true for other types of spacetime.

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5 hours ago, ravell said:

This is clearly presented in the previously given VETER program available on the link:

!

Moderator Note

You've been told at least three times that our rules state discussions must take place here at SFN, and that clicking on links is not a requirement for participation. Please show the evidence that supports your ideas here, and stop requesting that people go offsite. Links can be used to back up what you post here, but don't ask people to trust downloads. 

Also, you started out asking questions about mainstream physics, and have now given challenging assertions that aren't mainstream. I'm moving this to Speculations. Please support your arguments with evidence, and respond to calls for clarification.

 
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7 hours ago, ravell said:

 

Gravitational time dilation between two levels of different gravitation, is a phenomenon resulting from classical physics (Newtonian physics) 

 

!

Moderator Note

You've been asked several times to show this, and have deflected at each turn.

So now this is locked, and you are not permitted to bring the topic up again.

 
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