about Bob's article on absolute or relative time

Stripe

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The thread I'm referring to is here http://www.theologyonline.com/forums/showthread.php?p=850945#post850945 where Bob explains that time is absolute and not relative. He says that gravity affects clocks, not time.

Well, here is some guy claiming that he experienced time dilation by taking cesium clocks up Mt. Rainier. http://www.leapsecond.com/great2005/tour/

Thoughts?
The change in gravity affected the clock. Much the same way as gravity would influence a water clock being carried up a mountain. Much the same way as a change in gravity affects everything of mass.
 

Adam

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The change in gravity affected the clock. Much the same way as gravity would influence a water clock being carried up a mountain. Much the same way as a change in gravity affects everything of mass.
Thanks for your thoughts. I probably phrased it wrong. I agree with you and Bob that time doesn't dilate. I presented the link to all the readers because it was so similar to Bob's story.

Adam
 

Stripe

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The guy who did the experiment doesn't seem to realise the generally accepted explanation for his observations ..

"I'm not sure what "the hypothesis" is. I've read about relativity, true, but I just wanted to see if clocks actually ran at different
rates depending on altitude. Seems like it's true. I plan on more tests this or next year, time permitting."
 
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Johnny

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Stripe said:
The change in gravity affected the clock. Much the same way as gravity would influence a water clock being carried up a mountain.
A water clock does not rely on a fundamental process by which time itself is defined, whereas an atomic clock does.
 

Stripe

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A water clock does not rely on a fundamental process by which time itself is defined, whereas an atomic clock does.
What fundamental process defines time and why should we accept this definition when gravity can affect both?
 

Flipper

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He has not explicitly said so, but I wonder if Bob hasn't quietly revised his opinion of relativity since that thread?

He has certainly been very complimentary of Albert Einstein's genius since then.
 

Lighthouse

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He has not explicitly said so, but I wonder if Bob hasn't quietly revised his opinion of relativity since that thread?

He has certainly been very complimentary of Albert Einstein's genius since then.
Bob remains an open theist.
 

Flipper

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Well both special and general relativity require relative time.

I suppose Bob might like Einstein's paper on the photoelectric effect or be impressed by the awesome predictive power of his theories of relativity.

I doubt it's the latter though, because as I recall it, Bob compared the effectiveness of relativity to the failed epicycle theory which is, of course, a spurious comparison. After all, epicycles were developed to shoehorn existing observations into the assumed world view of the day, whereas GR was entirely theoretical in its inception, although it also built on special relativity which reconciled various experimental observations of the past that were not in accordance with Newtonian mechanics and also provided a theoretical framework by which physicists could dispense with the idea of luminiferous aether, an idea that was not supported by observation.

There have been a number of experimental tests of aspects of GR (not all of them involving clocks) and so far it has passed all of them. This is very significant because GR is a "sudden death" theory - if it fails any of the tests then it fails completely.

Even if it continues to be demonstrated in future experiments, we already know that GR is not completely correct because, like Newtonian mechanics, it doesn't tell the whole story: for example, it doesn't account for quantum gravity. However unless it is disproven by experimentation, any subsequent explanation will have to encompass GR in the same way that GR encompasses Newtonian mechanics.
 
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Stripe

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How do you test time without using a clock?
 

Johnny

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What fundamental process defines time and why should we accept this definition when gravity can affect both?
The event cycles at an absolute regular interval in its own inertial frame irrespective of the gravitational field or acceleration. This is the fundamental difference between your water clock analogy and an atomic clock. If you're carrying your water clock in different gravitational fields, you can look down and notice that the water is dripping slower. Your wristwatch will count off seconds different than the water clock. Whereas if you are carrying an atomic clock through a varying gravitational field, you will never notice the change in the clock. It will always tick off at a regular interval from your vantage point.
 

Stripe

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The event cycles at an absolute regular interval in its own inertial frame irrespective of the gravitational field or acceleration. This is the fundamental difference between your water clock analogy and an atomic clock. If you're carrying your water clock in different gravitational fields, you can look down and notice that the water is dripping slower. Your wristwatch will count off seconds different than the water clock. Whereas if you are carrying an atomic clock through a varying gravitational field, you will never notice the change in the clock. It will always tick off at a regular interval from your vantage point.
:squint: The experiment linked to showed the exact opposite. The experiment showed that the two clocks (on the mountain and off the mountain) ticked at different rates.
 

Stripe

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Stripe fundamentally not getting the "relative" part of relativity.
Flipper - I see no need to "get" relativity. There is no need to insist that anything other than the clock is being affected when you take it up a mountain.

It does not matter if the clock is highly accurate and not overly susceptible to gravitational effects or if it is inaccurate and very susceptible. Relativity simply is not a necessary consideration.
 

ThePhy

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The change in gravity affected the clock. Much the same way as gravity would influence a water clock being carried up a mountain. Much the same way as a change in gravity affects everything of mass.
A water clock depends for its functioning on the strength of gravity. Does a cesium clock? IOW, if you took a water clock and a cesium clock far out into interstellar space, would they be equally influenced by the reduction of gravity to almost zero?
 

Stripe

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A water clock depends for its functioning on the strength of gravity. Does a cesium clock? IOW, if you took a water clock and a cesium clock far out into interstellar space, would they be equally influenced by the reduction of gravity to almost zero?

They would not be affected to the same degree because they rely on different mechanisms. But clearly both are affected by gravity. So, no, they would not both be reduced to "almost zero", but that does nothing to show that time is being dilated.
 

ThePhy

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They would not be affected to the same degree because they rely on different mechanisms. But clearly both are affected by gravity. So, no, they would not both be reduced to "almost zero", but that does nothing to show that time is being dilated.
I agree. But your prior statement that I was responding to made it sound as though the change in gravity would not only affect them both, but affect them equally.
 
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