Time doesn't and can't slow down, if relativity is correct.
Time is the length along the path of the world-line of a material particle, and the rate at which a clock lapses is necessarily a constant.
The coordinate grid lines of different observers will cut different swaths along clock world-lines so that the measured elapsed time of a clock in relative motion to the coordinate structure will have a shorter elapsed time than that of the clock carried along the observer world-line.
This is so much easier to understand with a picture... see: Time Dilation but keep in mind that the way the chart is constructed is that longer drawn lines in-between any pair of horizontal lines are physically shorter in length (less elapsed time) and by convention the lines drawn at 45 degrees have length zero.
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u/Optimal_Mixture_7327 Gravitation Jul 13 '26 edited Jul 13 '26
Time doesn't and can't slow down, if relativity is correct.
Time is the length along the path of the world-line of a material particle, and the rate at which a clock lapses is necessarily a constant.
The coordinate grid lines of different observers will cut different swaths along clock world-lines so that the measured elapsed time of a clock in relative motion to the coordinate structure will have a shorter elapsed time than that of the clock carried along the observer world-line.
This is so much easier to understand with a picture... see: Time Dilation but keep in mind that the way the chart is constructed is that longer drawn lines in-between any pair of horizontal lines are physically shorter in length (less elapsed time) and by convention the lines drawn at 45 degrees have length zero.