39

POSIX time doesn't include leap seconds, and is not implemented the same way in every UNIX, so it routinely gets inconsistent for several seconds every couple of years. It is not a high-precision time scale, and there is little point correcting it for relativistic effects which are smaller than it can represent. GPS has to be corrected --- in particular, ...


30

No. Computer clocks are inaccurate. They rely on constant corrections to maintain the correct time. Since their inaccuracy is much bigger than the time speed difference between earth and the ISS, it really doesn't matter.


24

It doesn’t yet matter for most practical purposes. The slowdown from faster motion and speedup from a weaker gravitational field partly cancel out, and the net effect is that time on the ISS is only 0.0000000014% slower than time on Earth, so in its whole 22-year history it has lost about one hundredth of a second.


5

Computers on the ISS do not rely on UNIX/POSIX time, they rely on GPS time. Broadcast time is the time broadcast from ISS computers that is intended to be indicative of current time. The broadcast time message is with respect to the GPS time scale, not the Universal Time Coordinated (UTC) time scale. The time is accurate to ±1 s: Due to various reasons, ...


3

How are EMET and OMET defined? I understood the answer to be an example of what the timing on an interstellar mission would look like. In other words, the definitions of EMET and OMET are that answer. Are they for example what two ideal clocks initially set to UTC at the launch site would read if one remained at the launch site and the other remained in ...


2

I think (as with the other answer) that the referenced answer is really defining these terms. The following is an attempt to make sense of these definitions. My definitions below are, I think, compatible with those, but if they are not then I think they make sense in their own right. Note that I am not quoting sources for these definitions apart from the ...


2

The distance (and time) shrink from the viewpoint of the fast-moving object, but not from the viewpoint of a stationary observer.


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