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:
“The country is fed up with children and their problems. For the first time in history, the differences in outlook between people raising children and those who are not are beginning to assume some political significance. This difference is already a part of the conflicts in local school politics. It may spread to other levels of government. Society has less time for the concerns of those who raise the young or try to teach them.”
—Joseph Featherstone (20th century)