Gravitational time dilation

[D H]

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 ?

Let me see: four times five is twelve, and four times six is thirteen, and four times seven is -- oh dear! I shall never get to twenty at that rate! Ask nonsense questions and you should expect nonsense answers.

 

Your concept of a "Universal Time Unit" explicitly assumes something GR says cannot exist. There is no such thing as a global reference frame or a universal time standard.

[Bart]

Let me see: four times five is twelve, and four times six is thirteen, and four times seven is -- oh dear! I shall never get to twenty at that rate! Ask nonsense questions and you should expect nonsense answers.

 

Your concept of a "Universal Time Unit" explicitly assumes something GR says cannot exist. There is no such thing as a global reference frame or a universal time standard.

 

DH, does this mean that the ratio of the flashes period of the pulsar P2 to the period of pulsar P1 , which is invariable and is always equal to 100 000 (in this example), according to you is changing? How do you want to explain that to you here on Earth, suddenly one of the pulsar decreased or increased its rotation compared to the other one? Are you a magician?

[swansont]

DH, does this mean that the ratio of the flashes period of the pulsar P2 to the period of pulsar P1 , which is invariable and is always equal to 100 000 (in this example), according to you is changing?

The ratio can be constant and still not represent a constant interval. If they both changed by any constant multiplicative factor — as happens with time dilation — the ratio would remain the same. e.g. double both rates. The ratio is unchanged.

[Bart]

The ratio can be constant and still not represent a constant interval. If they both changed by any constant multiplicative factor — as happens with time dilation — the ratio would remain the same. e.g. double both rates. The ratio is unchanged.

 

I do not understand your position. The ratio of rotation period of the pulsar P2 to the pulsar P1 is always constant, and on any object in space is 100 000. We have taken the rotation period of the pulsar P1 as our universal time unit UTU, which makes that on every object in the universe, the rotation period of the pulsar P2 will always be measured as 100 000 UTU. Thus, time in the UTU units flows at the same rate on all objects in the space. Where do you see here, therefore, any time dilation measured in the UTU units?

 

[swansont]

I do not understand your position. The ratio of rotation period of the pulsar P2 to the pulsar P1 is always constant, and on any object in space is 100 000. We have taken the rotation period of the pulsar P1 as our universal time unit UTU, which makes that on every object in the universe, the rotation period of the pulsar P2 will always be measured as 100 000 UTU. Thus, time in the UTU units flows at the same rate on all objects in the space. Where do you see here, therefore, any time dilation measured in the UTU units?

 

I don't. That's the problem.

[Bart]

I don't. That's the problem.

 

Thank you for your response. Yes, it is a serious problem for the theory of relativity. Let's stop hiding our heads in the sand.

 

Brief description of this case is available at the link: http://dl.dropbox.com/u/26262175/GravitationalTimeDilation.pdf

 

 

 

 

 

[swansont]

Thank you for your response. Yes, it is a serious problem for the theory of relativity.

 

Not so much, considering the level of experimental support there is for relativity. How much is there for your alternative hypothesis?

 

Let's stop hiding our heads in the sand.

 

Yeah, kinda tough to read the results of actual (not thought) experiments in the dark.

[Bart]

Not so much, considering the level of experimental support there is for relativity. How much is there for your alternative hypothesis?

 

 

 

 

A more complete commentary on this thread is shown in the link: http://dl.dropbox.com/u/26262175/TimeInUniverse.pdf

 

I think that it is difficult to deny the conclusions presented in it.

 

This is no longer speculations, but given the real facts.

 

 

[ACG52]

I've read your link, and it's as vacuous as your posts here. In fact, it's the same as your posts here.

 

You've got assertions and unsupported conclusions. That's pretty much all there is.

[swansont]

A more complete commentary on this thread is shown in the link: http://dl.dropbox.com/u/26262175/TimeInUniverse.pdf

 

I think that it is difficult to deny the conclusions presented in it.

 

I think you have grossly overestimated the difficulty.

 

For example, you say that two clocks at different temperatures, i.e. different environmental conditions, will yield different time measurements. From that you imply that all different time measurements must be due to environmental effects. But the converse statement does not follow; this is an egregious error of logic.

 

This is no longer speculations, but given the real facts.

 

I had asked for experimental evidence and you have provided none. Your model is an assertion only. How could it be tested? How could it be used, in a way that relativity is used in GPS? Which depends on relativity and which works.

 

You seem to make a prediction that I could, for example, bake a cake and use the pulsar timing. Let's say it takes 100 ticks to bake the cake in one location. Your claim is equivalent to saying that it will take 100 ticks everywhere, even if I am in a place with a different gravitational potential (though the same value of g, so there are no other effects in play).

 

Since we can't do that, let's try another experiment. I will use your universal clock to measure the frequency of light at some location and the prediction seems to be that I will get the same answer everywhere, since it's universal time. So light emitted from a source should be on resonance and absorbed by an identical material, regardless of the gravitational potential of the emitter and absorber. So why doesn't this happen?

[ACG52]

What Bart is basically asking is 'what is the difference in time dilation between a gravitational field of 100 solar masses and a field of 1 earth mass.

 

I answered him in post #23.

[Bart]

I think you have grossly overestimated the difficulty.

 

For example, you say that two clocks at different temperatures, i.e. different environmental conditions, will yield different time measurements. From that you imply that all different time measurements must be due to environmental effects. But the converse statement does not follow; this is an egregious error of logic.

 

 

 

 

I am not saying that the time depends on the environment. I say that the ticking of the clocks is dependent on the physical conditions under which they work, which include: gravity, velocity, temperature, etc.

 

 

 

I had asked for experimental evidence and you have provided none. Your model is an assertion only. How could it be tested? How could it be used, in a way that relativity is used in GPS? Which depends on relativity and which works.

Please note that I do not question the correctness of the theory of relativity, in its calculation of the time dilation, but I question its interpretation of this fact, and this is something completely different.

 

The ticking frequency of the atomic clocks in GPS satellites are slowed down just before they are launched into orbit (to get 45-7=38 microseconds delay per day on the ground), so that once they are placed in their proper orbit, these clocks tick at the correct rate as compared to the reference atomic clocks at the GPS ground stations.

 

So this is fully consistent with my conclusion: The time dilation of clocks is in fact the immanent property (fault) of these tools, by which we measure the passage of time, and which may be late or fast in relation to the reference clock, for various legitimate reasons. Such clocks should just tune on site to the reference clock, and not to treat discrepancies of their tick as the time dilation.

 

 

 

You seem to make a prediction that I could, for example, bake a cake and use the pulsar timing. Let's say it takes 100 ticks to bake the cake in one location. Your claim is equivalent to saying that it will take 100 ticks everywhere, even if I am in a place with a different gravitational potential (though the same value of g, so there are no other effects in play).

 

Not at all. I do not say that your cake will need 100 ticks to be baked at any location in space, regardless of the conditions there. I claim that looking at your frying pan through a telescope from anywhere in the universe, I will always see that you are baking your cake for 100 ticks, it is the same as you. If in other conditions, you will need 90 ticks to bake your cake, then I will also see 90 ticks.

 

 

 

Since we can't do that, let's try another experiment. I will use your universal clock to measure the frequency of light at some location and the prediction seems to be that I will get the same answer everywhere, since it's universal time. So light emitted from a source should be on resonance and absorbed by an identical material, regardless of the gravitational potential of the emitter and absorber. So why doesn't this happen?

 

The frequency of light is exactly the same parameter as the frequency of atom cesium in the atomic clocks. Atomic clocks as a special kind of light clocks are dependent on gravity, speed and may be affected by magnetic and electric fields.

 

 

 

[swansont]

Not at all. I do not say that your cake will need 100 ticks to be baked at any location in space, regardless of the conditions there. I claim that looking at your frying pan through a telescope from anywhere in the universe, I will always see that you are baking your cake for 100 ticks, it is the same as you. If in other conditions, you will need 90 ticks to bake your cake, then I will also see 90 ticks.

 

Of what use, then, is your universal time, if one cannot use it to time anything?

[md65536]

What Bart is basically asking is 'what is the difference in time dilation between a gravitational field of 100 solar masses and a field of 1 earth mass.

 

I answered him in post #23.

 

No, I don't think that's right. He's asking how many ticks of one pulsar do you measure relative to the other pulsar. From what I read he didn't explain the difference in location/gravity/velocity between the pulsars... we can assume for the sake of his argument that they're essentially collocated, acting like different hands of a clock.

 

Everyone will agree on the number of P2 ticks per P1 tick, just like everyone will agree that a minute hand does 12 full rotations per rotation of an hour hand --- no matter how fast or slow those hands are observed to be turning.

 

 

What Bart seems to fail to realize is that

1) Such results are completely consistent with relativity. Specifically, what any observer measures is consistent with what any other observer measures, ie. reality is consistent, even with time dilation.

2) Such results are not good enough to define a clock. Choosing a universal clock would be arbitrary, and it would not be universally applicable, so calling it "universal" would be a mistake.

 

Yes Bart, your universal clock would is simpler, but it wouldn't suffice. Relativity (or this thread) doesn't disagree with all of your premises or evidence, only the conclusions that you're drawing from them.

Edited June 12, 2012 by md65536

[D H]

Yes Bart, your universal clock would be simpler.

Simpler? There isn't much that could make things harder. The laws of physics won't be the same from place to place. Fundamental constants aren't. What to do at some place that can't see the pulsars because they're occluded by a gas cloud? Synchronization from another location won't work. What to do at some other place that sees multiple images of the pulsar thanks to gravitational lensing?

[md65536]

Simpler? There isn't much that could make things harder. The laws of physics won't be the same from place to place. Fundamental constants aren't. What to do at some place that can't see the pulsars because they're occluded by a gas cloud? Synchronization from another location won't work. What to do at some other place that sees multiple images of the pulsar thanks to gravitational lensing?

 

It's not a question of practicality or functional simplicity, but theoretical simplicity. Having one useless clock is simpler than having an infinite number of independent useful clocks.

 

Practical problems can be solved, for example every local clock can compute a prediction of what the occluded pulsar is doing (then you have a simple clock definition with overly complex implementation).

 

Gravitational lensing should not be an issue. No observer will record that the pulsar ticked one billion times when viewed in one direction, but one and a half billion times when viewed in another. Even if the record of ticks gets out of sync, there should be an "official" relative time for any observer. For a single observer, it is never "two different times at once" at any given remote clock, so choosing a particular clock as a "master" clock isn't a problem. The time at the pulsar should be well defined according to any observer, with GR --- I think.

[ACG52]

No, I don't think that's right. He's asking how many ticks of one pulsar do you measure relative to the other pulsar. From what I read he didn't explain the difference in location/gravity/velocity between the pulsars... we can assume for the sake of his argument that they're essentially collocated, acting like different hands of a clock.

 

 

As I read it, he established a tick rate observed on a high gravity object, and then asked what would the tick rate be as observed on earth.

 

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 ?

 

[md65536]

As I read it, he established a tick rate observed on a high gravity object, and then asked what would the tick rate be as observed on earth.

Yes, but it's measured in "UTU", which would have a period that is time-dilated by the same (I'm assuming) factor as the P2 period.

 

 

 

It's useless as a local measure of time (baking cakes etc), but it's true that everyone would agree on the proper timing of events that happen at P1 or P2 (or anywhere). It's true that everyone who came together to compare notes would agree on the total number of pulses counted. Everyone everywhere would agree on what P2 sees (which is 100000 P1 pulses per P2 pulse, or whatever).

 

Any clock arbitrarily called a "master clock" will tell proper time consistently according to everyone, but will fail depending on reference frame to sync with local clocks (and processes like baking cakes etc). OP is concentrating on arguing that proper time is consistent (true), mistakenly thinking that that means that relativity must be wrong.

[Bart]

Of what use, then, is your universal time, if one cannot use it to time anything?

I think that you did not understand properly the presented ideas. If for all clocks in the universe will be applied a selected pulsar as the reference clock, instead of the local atomic clocks, then everywhere in the universe we will have measured time in the same universal units of time UTU (let's say universal seconds). Such clocks from the user point of view do not differ at all from the present clocks, but they provide the measurements of time at the same tick rate, everywhere in the space. So wherever you are on Earth, the Moon, or on any other object in space, the passage of time as measured on your watch will be exactly the same as on Earth, and the time dilation disappears from the physics textbooks, forever. So, these are the fundamental benefits of the universal time units UTU.

 

I stress it again that this is not speculation but the reality!

Edited June 13, 2012 by Bart

[D H]

I think that you did not understand properly the presented ideas.

I think that you did not understand properly the presented objections.

 

md65536 summed it up nicely with

It's not a question of practicality or functional simplicity, but theoretical simplicity. Having one useless clock is simpler than having an infinite number of independent useful clocks.

 

 

Bart, your concept is about as useful as an acquaintance's grandfather clock. It looks cool, but it doesn't work. He has it set at 12:00. It's exactly right twice a day. Plus it let's him say "Hey, look! It's noon already. I can start drinking!" (He has a slight problem with that.)

[swansont]

I think that you did not understand properly the presented ideas. If for all clocks in the universe will be applied a selected pulsar as the reference clock, instead of the local atomic clocks, then everywhere in the universe we will have measured time in the same universal units of time UTU (let's say universal seconds). Such clocks from the user point of view do not differ at all from the present clocks, but they provide the measurements of time at the same tick rate, everywhere in the space. So wherever you are on Earth, the Moon, or on any other object in space, the passage of time as measured on your watch will be exactly the same as on Earth, and the time dilation disappears from the physics textbooks, forever. So, these are the fundamental benefits of the universal time units UTU.

 

I stress it again that this is not speculation but the reality!

 

But you still have to apply the time dilation correction, because otherwise identical processes will no longer take the same time in different locations. Which is contrary to the whole basis of timekeeping. "Bake for 20 UTUs" will be meaningless in a recipe because you need to correct for your gravitational potential. Meaning that it's not "universal" at all. You will be unable to synchronize local clocks to the universal clock, because they run at different rates. Even under identical environmental conditions.

 

You can only get to your solution by redefining what we mean by time. And, as D H has pointed out, one of the ramifications is that the laws of physics will no longer be universal, and it is far, far more useful to have that.

[Bart]

But you still have to apply the time dilation correction, because otherwise identical processes will no longer take the same time in different locations. Which is contrary to the whole basis of timekeeping. "Bake for 20 UTUs" will be meaningless in a recipe because you need to correct for your gravitational potential. Meaning that it's not "universal" at all.

 

It's not like you mean it. Such a recipe for cake baking : "Bake for 20 UTUs" is useless wherever you baked this cake, even on Earth. If in the recipe you specify that cake should bake for 20 UTUs, at 200 ° C, at a pressure of air of 1 atm , etc. , then you bake this cake in 20UTUs in any place in universe.

 

You will be unable to synchronize local clocks to the universal clock, because they run at different rates. Even under identical environmental conditions.

It is not true. The ticking frequency of the local reference atomic clocks can be slowed down or speed up, its no problem, so these clocks will tick at the same rate as the reference pulsar clock.

 

You can only get to your solution by redefining what we mean by time. And, as D H has pointed out, one of the ramifications is that the laws of physics will no longer be universal, and it is far, far more useful to have that.

 

The existing laws of physics will not be affected in the slightest degree, just the contrary, they become more universal and explicit than it is today.

[ACG52]

Yes, but it's measured in "UTU", which would have a period that is time-dilated by the same (I'm assuming) factor as the P2 period.

 

 

 

 

 

The UTU is dependent on P1, but the number of UTU recorded on P2 and the number recorded on Earth will differ due to the different rate of time dilation between P2 and Earth.

[md65536]

The existing laws of physics will not be affected in the slightest degree, just the contrary, they become more universal and explicit than it is today.

The local speed of light expressed in terms of UTU will depend on your frame of reference.

As it is now, the local speed of light is invariant and universally equal to c.

There's a law that is affected, and doesn't become "more universal".

 

The UTU is dependent on P1, but the number of UTU recorded on P2 and the number recorded on Earth will differ due to the different rate of time dilation between P2 and Earth.

Yes, relative to local time.

 

Say that at P2, each P1 pulse takes 2 local P2-seconds. P2 sends out a pulse every 100,000 P1-pulses, so it sends out a pulse every 200,000 P2-seconds, or once every 100,000 UTU.

 

Say at Earth each P1 pulse takes 4 local Earth-seconds. Each P2 pulse takes 400,000 Earth-seconds, or 100,000 UTU.

 

(This assumes that P1 and P2 share a frame of reference, so that a "P1 second" is the same as a "P2 second". Ie. it assumes that P1 and P2 clocks are synchronized. As long as they're synchronized, they can be considered to be a single clock?)

[swansont]

It's not like you mean it. Such a recipe for cake baking : "Bake for 20 UTUs" is useless wherever you baked this cake, even on Earth. If in the recipe you specify that cake should bake for 20 UTUs, at 200 ° C, at a pressure of air of 1 atm , etc. , then you bake this cake in 20UTUs in any place in universe.

 

I thought the rest of the recipe was understood, but OK: you specify the environmental conditions. But it will not take 20 UTUs everywhere, under those same conditions.

 

 

It is not true. The ticking frequency of the local reference atomic clocks can be slowed down or speed up, its no problem, so these clocks will tick at the same rate as the reference pulsar clock.

 

And this is the reason. If you have to speed or slow your reference clock, you change the standard of time, using what we currently mean by time. If you have to slow your clock down then more than 1 actual second passes for each indicated second. Which means that 20 UTUs represents a longer elapsed time than for where no adjustment was necessary.

 

 

The existing laws of physics will not be affected in the slightest degree, just the contrary, they become more universal and explicit than it is today.

 

You need to demonstrate this. Do the equivalent of Einstein's derivations but under the assumption of invariant time. You cannot have it and the other postulates all be true. Something has to give.