The satellites "move faster" according to one frame of reference, but the point of relativity is that the answers are independent of frame of reference. From the satellite's point of view, we are moving more than they are.

The important thing is that satellites feel no acceleration. They are just floating (in orbit). Those of us "who are stuck in the muck of earth's gravity" feel about 1g of acceleration all of the time, and this slows down the passage of time for us.

If I jump into a space ship and fly far away at near the speed of light and then return at near the speed of light, I will have aged less than y'all. And I will have felt a lot of acceleration in getting up to speed and then in changing direction.

I was just reading "The Elegant Universe" and thought it got parts of the explanation of relativity wrong. But I eventually realized that most of the explanations I'd heard before got it wrong. The key point that prior explanations missed is that if you are moving relative to me, then it is quite complicated to compare our clocks accurately, since the time it takes signals to pass between us keeps changing. According to relativity, if we are both "coasting" but moving relative to each other, there really is no answer to "whose clock is running faster". You can look at things different ways and get different answers to that question, and each of those different answers is equally valid.

But if we move apart and then move back together again, then we can precisely compare how much time has passed on our different clocks. And the clock that has aged the least will be the one that experienced the most acceleration (as I currently understand things).

No, I'm not an expert on relativity, so I easily admit that I could have made any number of errors above.

- tye        

In reply to Re^7: Converting GPS seconds to readable time&date (acceleration) by tye
in thread Converting GPS seconds to readable time&date by flamey

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