Gravitational time dilation

Bart · May 23, 2012

Assume that the adopted standard of time in our region of the universe is a selected pulsar with a rotation cycle of 1 second,and that the clocks on Earth and on all other space objects, including those with very big mass, are synchronized by the pulses of the pulsar. Thus, these clocks will always indicate the same time, everywhere in space, regardless of the mass of the object upon which they are located. This example, therefore, contradicts the truth of the gravitational time dilation. Am I right?

Edited May 23, 2012 by Bart

pmb · May 23, 2012

Assume that the adopted standard time in our region of the universe is a selected pulsar with a rotation cycle of 1 second,and that the clocks on Earth and on all other space objects, including those with very big mass, are synchronized by the pulses of the pulsar. Thus, these clocks will always indicate the same time, everywhere in space, regardless of the mass of the object upon which they are located. This example, therefore, contradicts the truth of the gravitational time dilation. Am I right?

No. This doesn't account for gravitational time dilation. Clocks near gravitating bodies which generate a spacetime for which there is a spatial variation in [math]g_00[/math] will cause the local clock to run at a different rate as the distance source. If you locallysync that clock to the distance source then according to distant clocks they will be out of sync.

Bart · May 23, 2012

No. This doesn't account for gravitational time dilation. Clocks near gravitating bodies which generate a spacetime for which there is a spatial variation in [math]g_00[/math] will cause the local clock to run at a different rate as the distance source. If you locallysync that clock to the distance source then according to distant clocks they will be out of sync.

Thank you for responce. In my post the synchronization of the clocks should be understood remote timing of the clocks by 1 sec pulses from the pulsar.

md65536 · May 23, 2012

Thank you for responce. In my post the synchronization of the clocks should be understood remote timing of the clocks by 1 sec pulses from the pulsar.

pmb is saying that your method fails the following property of meaningful synchronization:

"(b2) the synchronisation is symmetric, that is if clock A is synchronised with clock B then clock B is synchronised with clock A,"

[http://en.wikipedia....synchronisation]

Edit: Well that's not quite what pmb said; I just didn't read it properly.

As well, with your method, some clocks would sometimes seem slow or fast... they would not meaningfully keep time. Time would not be regular or consistent. The speed of light wouldn't be invariable. Different clocks would not be synchronized to each other, only to the one "master clock", so it would also fail "(b3) the synchronisation is transitive, that is if clock A is synchronised with clock B and clock B is synchronised with clock C then clock A is synchronised with clock C."

Edited May 24, 2012 by md65536

elfmotat · May 24, 2012

Sure, you could synchronize all clocks to agree by correcting for velocity and gravitational time dilation, but this doesn't have any real physical meaning. It doesn't stop initially synchronized clocks from ticking at different rates according to altitude or velocity.

Bart · May 24, 2012

Sure, you could synchronize all clocks to agree by correcting for velocity and gravitational time dilation, but this doesn't have any real physical meaning. It doesn't stop initially synchronized clocks from ticking at different rates according to altitude or velocity.

I think we should separate the concept of time dilation, from the possible dilation of clocks indications, which for the clocks not using the pulsar signal can be fast or slow,depending on the clock design. My understanding of this case was different. In this example, all clocks in space are clocked remotely using a standard time signal which is generated from the pulsar. Thus, all clocks in space will run exactly with the same rhythm of time, and one minute, one hour, etc on Earth has the same time length as on any other obiect in space. Thus, regardless of the construction and location of clocks in space, the passage of time indicated on each clock in space will always be the same, and there is no room for any time dilation.

Edited May 24, 2012 by Bart

**swansont** · May 24, 2012

I think we should separate the concept of time dilation, from the possible dilation of clocks indications, which for the clocks not using the pulsar signal can be fast or slow,depending on the clock design. My understanding of this case was different. In this example, all clocks in space are clocked remotely using a standard time signal which is generated from the pulsar. Thus, all clocks in space will run exactly with the same rhythm of time, and one minute, one hour, etc on Earth has the same time length as on any other obiect in space. Thus, regardless of the construction and location of clocks in space, the passage of time indicated on each clock in space will always be the same, and there is no room for any time dilation.

Clock design is probably irrelevant since we don't seem to be discussion the technical difficulties of timekeeping but rather the limitations placed by relativity. i.e. there the problems present when you assume ideal clocks, and the additional problems you introduce when you bring real clocks into the discussion.

If you have ideal clocks in different gravitational potentials, they will not synchronize with both the pulsar and with each other.

md65536 · May 24, 2012

Thus, regardless of the construction and location of clocks in space, the passage of time indicated on each clock in space will always be the same, and there is no room for any time dilation.

Only because you've defined it out of existence.

Consider a twin paradox where two twins are separated as children and reunite later, and one seems middle-aged and the other seems very old. They compare clocks, and they agree that they have each observed a billion signals from the pulsar. They have each aged about 31 years. They agree that they are the same age.

If they each had a watch with them, the older twin will have had to adjust her watch often to keep it in sync with the pulsar, as the pulsar signals often arrived less frequently (and sometimes more frequently) than the watch ticked.

Likewise, all the time-related processes in the body would also run at the pace of a local clock, not caring what some remote pulsar is doing. The body ages like a crude clock... and how do you force your body to synchronize with a pulsar?

Bart · May 24, 2012

Clock design is probably irrelevant since we don't seem to be discussion the technical difficulties of timekeeping but rather the limitations placed by relativity. i.e. there the problems present when you assume ideal clocks, and the additional problems you introduce when you bring real clocks into the discussion.

If you have ideal clocks in different gravitational potentials, they will not synchronize with both the pulsar and with each other.

This case has no relation with ideal clocks that do not exist, but relates to the real clocks that work, let's say, in the vast space web of time, working in master-slave mode, in which the pulsar is the master clock and the slave are the clocks on all other objects in space. Such a network is similar to the typical solution that has been used and still is, in a distributed clock networks in offices and factories. So the theory of relativity has nothing to do here and any time dilation for the clocks does not occur here at all.

**swansont** · May 24, 2012

This case has no relation with ideal clocks that do not exist, but relates to the real clocks that work, let's say, in the vast space web of time, working in master-slave mode, in which the pulsar is the master clock and the slave are the clocks on all other objects in space. Such a network is similar to the typical solution that has been used and still is, in a distributed clock networks in offices and factories. So the theory of relativity has nothing to do here and any time dilation for the clocks does not occur here at all.

Then you are not doing any synchronization, as such. You have a clock and are broadcasting a signal, but the recipients of that signal are just displays. You aren't doing timekeeping. It can be done, but it's not particularly useful. You can't make meaningful comparisons.

Bart · May 25, 2012

Likewise, all the time-related processes in the body would also run at the pace of a local clock, not caring what some remote pulsar is doing. The body ages like a crude clock... and how do you force your body to synchronize with a pulsar?

1.The aging of the body has no connection with the tick rate of any remote or local clocks. It is a biological process which runs according to the rate of its chemical process , which in turn depend on the physical environment in which this body resides.

Examples:

- The body badly nourished and hard-working is aging faster than the body well fed and rested.

- The body in hibernation, practically not age at all. Time is stopped for it.

- The same chemical reactions proceed more slowly at low temperatures and faster at higher temperatures.

2.Relativistic gravitational time dilation is just a technological feature of the light clocks, which does not apply to passage of time itself.

According to the GR theory, time indicated by such clocks at the poles of Earth, runs slower than at the equator, due to the difference of gravity. But whereas the other clocks, pendulum clocks, using just gravity, indicate that the time run faster at the poles than at the equator.

Thus, the indication of which of these clocks show the correct passage of time on the Earth?

No response !

The conclusion is that the measurement of time must always be referred to some accepted reference clock, and must be counted in the same units for all clocks.

Such a reference clock in space could be the selected pulsar, and its period of flashes (eg 1 second) as the standard unit of time for all clocks.

3. The real passage of time in space, thus not dependent on the local clocks.

At the fixed time unit, the Earth's rotation period of 24 hours and the Earth's orbital period around the Sun amounting to 365 * 24 hours, will be the same for every observer in space, regardless of the mass of the object on which he is located.

Edited May 25, 2012 by Bart

**swansont** · May 25, 2012

2.Relativistic gravitational time dilation is just a technological feature of the light clocks, which does not apply to passage of time itself.

On the contrary, time dilation affects clocks of any construction equally, because it is an effect on time rather than a mechanical effect (i.e. a force)

According to the GR theory, time indicated by such clocks at the poles of Earth, runs slower than at the equator, due to the difference of gravity. But whereas the other clocks, pendulum clocks, using just gravity, indicate that the time run faster at the poles than at the equator.

Thus, the indication of which of these clocks show the correct passage of time on the Earth?

The period of a pendulum clock has an explicit dependence on g, for which you must compensate. In reality, clocks on the geoid at the equator or poles would run at the same rate, since the kinematic and gravitational terms cancel.

No response !

You do realize you have to wait for a response, don't you?

The conclusion is that the measurement of time must always be referred to some accepted reference clock, and must be counted in the same units for all clocks.

Conclusions based on flawed logic are invalid.

Bart · May 26, 2012

On the contrary, time dilation affects clocks of any construction equally, because it is an effect on time rather than a mechanical effect (i.e. a force)

The period of a pendulum clock has an explicit dependence on g, for which you must compensate. In reality, clocks on the geoid at the equator or poles would run at the same rate, since the kinematic and gravitational terms cancel.

You do realize you have to wait for a response, don't you?

Conclusions based on flawed logic are invalid.

Let's leave then the Earth's poles and equator and take another example:

Light-clock and the pendulum clock, are placed on the ground floor of a tower, and have identical time indication with the third reference clock on this floor. After moving light-clock and pendulum clock to the 50 floor of the tower, these clocks will have different indications of time. The light-clock will be fast, and the pendulum clock will be late relative to the reference clock left on the ground floor.

We see then that this or that time dilation is associated with the construction of the clocks, not with time itself.

As for the "No response !", it was just kind of thought shortcut, that the answer to the question raised is not so obvious. Sorry about that, but English is not my home language.

Many thanks for your comments, but there are no convincing arguments in your opinion that the claim: "the measurement of time must always be referred to the some accepted reference clock, and must be counted in the same units for all clocks" - is invalid. So, I still stand by my conclusion.

Edited May 26, 2012 by Bart

**swansont** · May 26, 2012

Let's leave then the Earth's poles and equator and take another example:

Light-clock and the pendulum clock, are placed on the ground floor of a tower, and have identical time indication with the third reference clock on this floor. After moving light-clock and pendulum clock to the 50 floor of the tower, these clocks will have different indications of time. The light-clock will be fast, and the pendulum clock will be late relative to the reference clock left on the ground floor.

We see then that this or that time dilation is associated with the construction of the clocks, not with time itself.

As for the "No response !", it was just kind of thought shortcut, that the answer to the question raised is not so obvious. Sorry about that, but English is not my home language.

Many thanks for your comments, but there are no convincing arguments in your opinion that the claim: "the measurement of time must always be referred to the some accepted reference clock, and must be counted in the same units for all clocks" - is invalid. So, I still stand by my conclusion.

I guess I have to repeat myself: The period of a pendulum clock has an explicit dependence on g, for which you must compensate. i.e. when you move the clock, it has a new frequency, and you have to use that new value. You don't get to ignore it, but neither do you get to write it off as time dilation, because it isn't.

Janus · May 26, 2012

Let's leave then the Earth's poles and equator and take another example:

Light-clock and the pendulum clock, are placed on the ground floor of a tower, and have identical time indication with the third reference clock on this floor. After moving light-clock and pendulum clock to the 50 floor of the tower, these clocks will have different indications of time. The light-clock will be fast, and the pendulum clock will be late relative to the reference clock left on the ground floor.

We see then that this or that time dilation is associated with the construction of the clocks, not with time itself.

Not at all.

Let's assume that each set of clocks has an identical accelerometer with it. The ground floor pendulum notes that the reading on its accelerometer, when plugged into the pendulum equation gives an answer that matches its measured period. However, when it checks out the 50th floor accelerometer and its pendulum clock, it will note that the measured period of the clock will be less than that predicted by its accelerometer and the pendulum equation. The difference equates to the same factor as due to the time dilation measured by the light clocks. In other words, the pendulum clocks are effected by both the difference in local g and gravitational time dilation.

Any type of clock placed on the 50th floor will be effected by gravitational time dilation when compared to the ground floor clock regardless of any other factors that might effect it operation. If I make two wind up clocks and design one so that it ticks half as slow as the other when they run side by side, and then put the slower running one on the 50th floor, it will now run just a bit faster than half as slow as the ground clock.

Gravitational time dilation is not due to any "physical" effect on the clocks, it is due to how the measurement of time and space itself behaves. If I were to place two identical clocks in a uniform gravity field (one that does not change strength with height), the clock placed higher in the field would still run faster, even if though the g forces and every other physical influence acting on the clocks are exactly the same.

ACG52 · May 27, 2012

It should also be noted that gravitational time dilation is a factor which must be constantly compensated for by GPS satellites, by a factor much larger than time dilation due to differences in relative velocities.

It's something real, and if you use a gps device, it effects you every time you use it.

Edited May 27, 2012 by ACG52

Bart · May 27, 2012

I guess I have to repeat myself: The period of a pendulum clock has an explicit dependence on g, for which you must compensate. i.e. when you move the clock, it has a new frequency, and you have to use that new value. You don't get to ignore it, but neither do you get to write it off as time dilation, because it isn't.

So let's look at the relationship of the clocks in question from g:

The period of the pendulum clock: T = 2pi (L / g) ^0.5 , (g = GM / R ^ 2)

The period of the light clock: T = To / (1-gR / c ^ 2) ^ 0.5

Where: To - the period of the light clock ticking in the absence of gravity (g = 0)

Why then, it is believed that when moving the clocks from the ground floor onto 50th floor, which results in a change to these clocks the value of g from g1 to g2, a compensation of this change is only required for the pendulum clock, and is not required for the light clock?

Why it is claimed that light clocks always show the correct time on the site, and other types of clocks require revisions?

Why it is believed that indications of the light clocks are invariant and that time is just variable and flows faster or slower depending on the g? Can anyone deny that the duration of any event anywhere in the universe, if measured by the same units of time (eg flashes of the selected pulsar) will always be the same for every observer in space, regardless of the mass of the object on which he is located?

So I repeat my thesis here, that the time dilation should be understood as a divergence of indication of the clocks, because of the way they work, and not as the change of passage of time itself, which can not depend on the construction of one or other of the clock.

Edited May 27, 2012 by Bart

ACG52 · May 27, 2012

Since there are neither swinging pendulums or bouncing beams of light on GPS satellites, how do you account for the fact that continuous adjustment is necessary to the clocks to keep them in sync, and that the adjustment needed is exactly that predicted by both SR and GR?

How do you account for the extended lifetime of muons traveling at relativistic speeds? Or the differences between identical atomic clocks at different velocities and altitudes?

The change in the rate time passes does not depend at all on the construction of the clock. There is a wealth of experimental confirmation that both relativistic and gravitational time variablilty is the way the universe really works.

Edited May 27, 2012 by ACG52

**swansont** · May 27, 2012

So let's look at the relationship of the clocks in question from g:

The period of the pendulum clock: T = 2pi (L / g) ^0.5 , (g = GM / R ^ 2)

The period of the light clock: T = To / (1-gR / c ^ 2) ^ 0.5

Where: To - the period of the light clock ticking in the absence of gravity (g = 0)

As Janus has pointed out, the pendulum clock also requires a correction for gravitational time dilation.

Why then, it is believed that when moving the clocks from the ground floor onto 50th floor, which results in a change to these clocks the value of g from g1 to g2, a compensation of this change is only required for the pendulum clock, and is not required for the light clock?

Nobody is claiming this. Both require dilation corrections. The pendulum clock, though, requires compensation of its frequency, because its frequency explicitly depends on g, and g changes. The dilation correction, though, is not because of a change in g. If you could maintain g as constant, you'd still see time dilation.

Why it is claimed that light clocks always show the correct time on the site, and other types of clocks require revisions?

Nobody is claiming this, either.

Why it is believed that indications of the light clocks are invariant and that time is just variable and flows faster or slower depending on the g?

It isn't. Gravitational time dilation depends on the gravitational potential, not the local value of g.

Can anyone deny that the duration of any event anywhere in the universe, if measured by the same units of time (eg flashes of the selected pulsar) will always be the same for every observer in space, regardless of the mass of the object on which he is located?

Any competent physicist can.

So I repeat my thesis here, that the time dilation should be understood as a divergence of indication of the clocks, because of the way they work, and not as the change of passage of time itself, which can not depend on the construction of one or other of the clock.

Clocks that work in multiple ways all see the same effect. How do you explain that?

Janus · May 27, 2012

So let's look at the relationship of the clocks in question from g:

The period of the pendulum clock: T = 2pi (L / g) ^0.5 , (g = GM / R ^ 2)

The period of the light clock: T = To / (1-gR / c ^ 2) ^ 0.5

Where: To - the period of the light clock ticking in the absence of gravity (g = 0)

Why then, it is believed that when moving the clocks from the ground floor onto 50th floor, which results in a change to these clocks the value of g from g1 to g2, a compensation of this change is only required for the pendulum clock, and is not required for the light clock?

Why it is claimed that light clocks always show the correct time on the site, and other types of clocks require revisions?

First off, where did you get the idea that Gravitational time dilation requires light clocks? All clocks are equally subject to gravitational time dilation. In fact, the best clock for the demonstration of gravitational time dilation would be the "ideal" clock, or a clock which is not effected by local conditions and is 100% accurate at all times.

Why it is believed that indications of the light clocks are invariant and that time is just variable and flows faster or slower depending on the g?

It doesn't depend on g. The difference in time rate depends on a difference of gravitational potential. For example, Take two identical clocks, place one the surface of the Earth and the other on the surface of Uranus, and arrange for them to be in identical environmental conditions (temp, pressure etc.) with the sole exception of g force. The clock on Uranus will run slower. However, the actual g force on the surface of Uranus is less than that of the Earth. The clock experiencing the lower g force will run slower.

Can anyone deny that the duration of any event anywhere in the universe, if measured by the same units of time (eg flashes of the selected pulsar) will always be the same for every observer in space, regardless of the mass of the object on which he is located?

So I repeat my thesis here, that the time dilation should be understood as a divergence of indication of the clocks, because of the way they work, and not as the change of passage of time itself, which can not depend on the construction of one or other of the clock.

And I'll repeat, gravitational time dilation does not depend on the construction of the clock. Nor does it depend on local conditions. This is what separates it from effects such as the local g force which is a factor in the operation of a pendulum clock.

Once again you have shown that you have failed to grasp the concept behind a Relativistic effect and turned that failure into a perceived flaw in the theory in your own mind.

Bart · May 28, 2012

Can anyone deny that the duration of any event anywhere in the universe, if measured by the same units of time (eg flashes of the selected pulsar) will always be the same for every observer in space, regardless of the mass of the object on which he is located?

Swansont wrote: Any competent physics can.

Thus, consider the following example:

In the distant space, we have chosen two pulsars for measurement of time, pulsar P1 and pulsar P2, both with the very stable generation of signals (flashes). Pulsar P1 generates flashes of very high frequency, and the pulsar P2 of very slow frequency. Assume the period of flashes of the pulsar P1 as the Universal Time Unit (UTU). Our measuring robot placed on some very massive object in space, which mass is 100 times larger than our Sun, but of the same radius, has measured the period of flashes of the pulsar P2 as exactly equal to the 100 000 UTU (100 000 pulses of pulsar P1).

Question: What will be the period of flashes of the pulsar P2 in UTU units, if measured on Earth ?

Bart · May 31, 2012

Swansont wrote: Any competent physics can.

Thus, consider the following example:

In the distant space, we have chosen two pulsars for measurement of time, pulsar P1 and pulsar P2, both with the very stable generation of signals (flashes). Pulsar P1 generates flashes of very high frequency, and the pulsar P2 of very slow frequency. Assume the period of flashes of the pulsar P1 as the Universal Time Unit (UTU). Our measuring robot placed on some very massive object in space, which mass is 100 times larger than our Sun, but of the same radius, has measured the period of flashes of the pulsar P2 as exactly equal to the 100 000 UTU (100 000 pulses of pulsar P1).

Question: What will be the period of flashes of the pulsar P2 in UTU units, if measured on Earth ?

No response?

So it just means, that all agree with the fact that the period of the flashes of pulsar P2, if measured on the Earth, will also amount to 100 000 UTU, which is the same as measured on any other object in the universe, regardless of its mass.

Thus, this example provides confirmation that the time flows everywhere at the same rate, independent from the local clocks, which may be late or fast due to various reasons.

And also, this example confirms that the interpretation of time dilation according to the theory of relativity is evidently erroneous.

So it's probably time to radically revise our current understanding and interpretation of the relativity theory as a whole.

Many thanks to All for your comments.

Bart

Edited May 31, 2012 by Bart

ACG52 · May 31, 2012

Able to leap tall conclusions in a single bound...

If I've done the calculation correctly, (which I must admit, I doubt), then on earth, we would observe 99956 UTU.

Edited May 31, 2012 by ACG52

md65536 · May 31, 2012

Thus, this example provides confirmation that the time flows everywhere at the same rate, independent from the local clocks, which may be late or fast due to various reasons.

If you're willing to sacrifice the usefulness of clocks in order to try to force uniform values, I have an improvement for you.

My clock is a metal sphere. The time is always t=1, from anywhere in the universe. You don't even need to observe the clock. All events and all local clocks (basketballs, marbles, etc) agree that the time will always be 1.

This example confirms that time is a constant and doesn't change.

So it's probably time to radically revise our current understanding and interpretation of the relativity theory as a whole.

I agree that an improvement in our current understanding of relativity would be helpful.

ACG52 · June 1, 2012

In an interview given (I think) in 1919, after the confirmation of Mercury's precession, a reporter said to David Eddington that only 4 people understood Einstein's theory of Relativity. Eddington was silent for a moment, and the reporter asked what he thought of that, and Eddington replied, 'I'm trying to think of who the other three are".

Edited June 1, 2012 by ACG52

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