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C47man t1_ja3aq3e wrote

Reply to comment by Darkeyescry22 in How old is the ISS REALLY? by gwplayer1

>Wouldn’t this make it a quarter of a second older than it would have been? Or is the observer someone on earth?

Time passes normally in the reference frame of the ISS, while Earth time goes faster. In the reference frame of Earth, the ISS ages slower. It doesn't matter which frame of reference you use.

>Also, do you know the calculation for general relativity? Is that effect (from being farther from earth) near the same order of magnitude, or much smaller?

What effect? "general relativity" is vague.

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Lashb1ade t1_ja3c41j wrote

"General relativity" would refer to time dilation due to gravity; the ISS is higher up in Earth's gravity well, so will age faster than on the Earth's surface.

I can never remember which of the two effects is larger.

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somdude04 t1_ja3f55p wrote

Moving fast is stronger. About 14 ms per year slower due to moving fast versus .3 ms per year from lower gravity at ISS orbit.

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