I'm a bit confused about how time can be relative. Example: if a cosmic event happened that could be observed from earth, multiple times, because light from this event reached earth at different times because of spacetime distortion due to a planets partial obstruction. Does it not just mean that the light reached the earth at different times? and the event itself happened at a time that is absolute? Put another way: if someone shoots a rifle in a field at exactly 1pm and there are two observers. One observer is closer than the other; they would hear the sound from the rifle shot at different times from one another and of course neither would hear it at the actual time the rifle was fired. However the time of the event didn't change, it still happened at exactly 1pm. So how is time relative? I mean, I understand how it can be perceived as relative, but it isn't really...?
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4$\begingroup$ After correcting for the time it takes light or sound to travel, observers who are stationary with respect to the source will agree on the time at which the signal originated. This has nothing to do with relativity, which involves observers who are in motion with respect to each other, and who do not agree on the timing of distant events even after correcting for the travel time of the signal. $\endgroup$– WillOCommented Aug 23, 2017 at 0:32
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$\begingroup$ Makes sense, thanks. My question is now irrelevant, can it be closed? $\endgroup$– ChrisCommented Aug 23, 2017 at 0:41
1 Answer
The main problem is in our imagination - we are not able to understand things without our personal experience. And values of speed witch are close to the speed of light are one of them.
There is no something as absolute 1:00 pm. It is our local time (the Earth's).
To be able to set 1:00 pm, people have to agree about some event, e. g. the certain position of the hands of the certain clock.
No problem for us because we people - within the same frame of reference - are able to simultaneously cry out "now it happens!"
But the problem is set 1:00 pm absolutely - for all frames of reference (or even for 2 ones different enough).
So your event of riffle's shoot didn't happen at exactly 1:00 pm - it happened in the same time in one particular frame of reference, the ours, and in which we were able to agree what does it mean 1:00 pm.
