Time dilation

Measured time difference as explained by relativity theory

Time dilation is the difference in elapsed time as measured by two clocks, either because of a relative velocity, a consequence of special relativity, or a difference in gravitational potential between their locations due to gravitational time dilation. When unspecified, "time dilation" usually refers to the effect due to velocity. The dilation compares co-moving clock readings between events measured in different inertial frames and is not observed by visual comparison of clocks across moving frames.

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