Are time dilation experiments conclusive?

[mfb]

The GPS satellites are influenced by the gravity of the Earth and their clocks are emitting and summing radiation in all directions at once. They rely on the transition of an electron from one shell to another to emit the radiation. And since this is strictly a random occurrence, the transition can be in any direction. The light emitted is then generally collected through mirrors to concentrate and direct it to series of items to detect its frequency. Since all there is to work with is the "summation" of many photons having been emitted in many directions they are not looking at the effect of EACH pulse, but rather the statistical sum of many. So, there is no way to accurately detect the individual photons and determine each frequency. And how one would make sure to detect only those photons emitted when the electrons were traveling in a certain direction would represent considerable technological problems. This just builds error after error into the system that would probably swamp any effect you may find.
The statistical nature of atomic clocks only says that we can average the results of many photons being emitted. Electrons traveling in an orbit around an atom are not in nice circles. As a matter of fact they are in a relatively thick cloud around the shells average size, and very few of the electron transitions are at the published frequency, on an individual basis they are quite varied and only their average is the published value.

This is not how GPS works at all.

 

[Gaz]

how does a atomic clock work then mfb?

 

[Gaz]

ok the life span of atoms are increased by motion and gravity as there slowed down. But aren't the atoms that I am composed of going to be around long after I am dead. So my question now is what is the connection between the lifespan of a atom and my lifespan? Does a atom slowing down mean time as I am experience it is really slowing down? I highly doubt that there is any experiment ever done to prove this one but would be interested to know. Why don't they just put something like a plant (many plants) on a little satellite and blast it around in a orbit as fast as they can to see if it actually grows slower?

 

[Markus Hanke]

Does a atom slowing down mean time as I am experience it is really slowing down?

Neither an atom nor the time you experience "slows down" in any meaningful sense of the word - if you hold a clock in your hand, it will never go slower than exactly one second per second. What happens is that your relationship in space-time with respect to some far-away reference clock changes. It is crucial to understand this difference - gravitational time dilation is not something that "happens" to an isolated frame, it is a relationship between clocks at different places. Time is not an entity that "flows" like a river, or can be given mechanical attributes - time is what clocks measure, a relationship between events.

So my question now is what is the connection between the lifespan of a atom and my lifespan?

The ratio between the two is constant everywhere; like I said, an isolated clock is never seen to be dilated in its own rest frame.

 

[phinds]

The ratio between the two is constant everywhere; like I said, an isolated clock is never seen to be dilated in its own rest frame.

I agree w/ the rest of your post, but I think this part is well-intentioned but misleading. Locally, what you are saying is correct, but the fact that nothing is time dilated in its own frame does NOT mean that life-spans are identical in all cases, as is shown clearly by the "twin paradox".

 

[mfb]

how does a atomic clock work then mfb?

That was not the question.
It is also not a good description of atomic clocks, but that is a completely different topic.

 

[Markus Hanke]

Locally, what you are saying is correct

I only meant it locally. Of course, if you have two frames tracing out different world lines between the same set of events, you will get different accumulated times. Still, neither of them would notice anything special happen to their clocks, they would just find that the readings disagree once the clocks are brought back together at rest.

 

[Gaz]

That was not the question.
It is also not a good description of atomic clocks, but that is a completely different topic.

I was only asking out of interest mfb because it seemed like what Bruce was saying could have made sense.
I see you said that is not how the GPS system works not the clock sorry =).

The ratio between the two is constant everywhere; like I said, an isolated clock is never seen to be dilated in its own rest frame.

the relationship between the two is constant doesn't really answer my question Markus mate. I want to know if a atoms frequency changing with motion would really effect time as I know it. I don't see how it would like I'm thinking a atomic clock that runs by the frequency of a atom might but a mechanical clock would work the same regardless of a atoms frequency.

 

[mfb]

I want to know if a atoms frequency changing with motion would really effect time as I know it.

It is the opposite way. The motion through spacetime determines the frequency each observer will see. This is not limited to individual atoms or clocks, it is true for every system.

I was only asking out of interest mfb because it seemed like what Bruce was saying could have made sense.

Just a few points, I don't want to go into detail as this is the wrong thread:
- the emission is not in random directions, the atoms are kept in a microwave cavity. There are no "mirrors" directing radiation to whatever.
- atomic clocks rarely use transitions between shells, but transitions within a shell. The GPS satellites in particular use a hyperfine transition of caesium.
- there is no need to detect individual photons as all have the same frequency. Doppler broadening is an issue, but does not change the central value.
- the model of electrons moving around the atom is so horribly outdated that I won't comment it further.
- and all this has nothing to do with GPS and measurements of time dilation

Edit: fixed grammar

 

[Dale]

I don't see how it would like I'm thinking a atomic clock that runs by the frequency of a atom might but a mechanical clock would work the same regardless of a atoms frequency

That would violate the principle of relativity.

 

[phinds]

I only meant it locally ...

I assumed that you knew that, my point was that your statement, sans caveat, might be confusing to less informed members reading your post.

 

[OCR]

GPS means, Global Positioning System... Not, Global Positioning System sys ... bah, never mind.

Get some cash from an ATM machine, too......

 

[Markus Hanke]

I assumed that you knew that, my point was that your statement, sans caveat, might be confusing to less informed members reading your post.

Point taken. I'll be more careful in the future

 

[phinds]

GPS means, Global Positioning System... Not, Global Positioning System sys ... bah, never mind.

Get some cash from an ATM machine, too......

Actually, the original name was the Global Positioning Satellite System, so GPSS used to be correct, but "GPS System" has never really been correct.