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Are the experiments that prove that time dilation exists, actually proving that an atomic clocks ability to keep time is affected by gravity/acceleration? How do we know 100% that that is not the case?

I am having trouble wrapping my head around how and why time dilation happens. I am not looking for a math explanation in any sense at all but a practical one. You can explain to me mathematically how a spinning spaceship creates a sense of gravity for people inside but I can take a bucket of water and spin it around and see and experience why that happens quite easily.

Is there any clear, practical explanation like this for time dilation?

Secondly how is this actually proven? How do we know for sure that atomic clock's frequencies don't fluctuate as gravity/acceleration changes? How do we know we are actually measuring "time"

zoplonix
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  • related: http://physics.stackexchange.com/a/15692/23473, http://physics.stackexchange.com/q/33863/23473 – Jim Nov 24 '14 at 16:10
  • See the middle two paragraphs of my answer here, as a philosophical matter you are free to take the interpretation that there is some sort of absolute reference frame and that clocks moving relative to it tick slower, but relativity predicts there's absolutely no way to experimentally show that one frame's definition of time is more "absolute" than any other, and from an experimental perspective the slowing of clocks moving inertially relative to one another is reciprocal (I measure your clock running slow, you measure mine running slow). – Hypnosifl Nov 24 '14 at 16:24
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    I think the best argument that it isn't faulty atomic clocks is that muons travel much farther than expected / calculated before decaying when traveling at high speeds. – Brandon Enright Nov 24 '14 at 16:47
  • @Brandon Enright - But I think the question is a more abstract one, asking why, even if moving clocks do all slow down in the same way as predicted by SR, we couldn't explain this by saying the clocks' "ability to keep time is affected by gravity acceleration" rather than "actually measuring 'time'". Like I said in my comment, this is really more a philosophical matter, SR as a theory of physics doesn't require you to favor either conceptual picture. – Hypnosifl Nov 24 '14 at 17:33
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    I'm going to disagree about the it being philosophical. Time is what clocks measure, and all clocks measure the same effect. Without exception. Essentially everyone asks this questions at some point because time dilation is offensive to what we think we know about the way the world works, but we're wrong about that knowledge. Nor can you just wave your hands and blame it on gravity without offering some kind of mechanism that affects all clocks alike. – dmckee --- ex-moderator kitten Nov 24 '14 at 17:51
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    @dmckee "Time is what clocks measure" is that the only possible definition of time? –  Nov 24 '14 at 19:43
  • @dmckee - People who believe in absolute time and space wouldn't agree that "time is what clocks measure", so if you say they're wrong, then either you yourself are making a philosophical claim, or you're just making a statement about the definition you prefer to use (since it's the only useful one in a scientific context) while remaining agnostic about whether there might be some metaphysically meaningful notion of "time". – Hypnosifl Nov 24 '14 at 20:50
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    "Time is what clocks measure" is a tautology. Time is an expression of the fact that two events that happen in the same place can none-the-less be separate from one another. The separation is the time (duration) between them. A device which allows you to compare intervals in that separation is a clock. The phrase can be taken as a definition of a clock as easily as of time, but it is true. To suggest that there is some underlying more correct time you must show that there is a way to measure it. – dmckee --- ex-moderator kitten Nov 24 '14 at 21:12

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