Time Dilation

In the theory of relativity, time dilation is an actual difference of elapsed time between two events as measured by observers either moving relative to each other or differently situated from gravitational masses.

An accurate clock at rest with respect to one observer may be measured to tick at a different rate when compared to a second observer's own equally accurate clocks. This effect arises neither from technical aspects of the clocks nor from the fact that signals need time to propagate, but from the nature of spacetime itself.

Read more about Time Dilation:  Overview, Simple Inference of Time Dilation Due To Relative Velocity, Time Dilation Due To Relative Velocity Symmetric Between Observers, Experimental Confirmation, Time Dilation and Space Flight

Famous quotes containing the word time:

    After I discovered the real life of mothers bore little resemblance to the plot outlined in most of the books and articles I’d read, I started relying on the expert advice of other mothers—especially those with sons a few years older than mine. This great body of knowledge is essentially an oral history, because anyone engaged in motherhood on a daily basis has no time to write an advice book about it.
    Mary Kay Blakely (20th century)