Time dilation is a phenomenon in physics that occurs when the passage of time is experienced differently by observers in different frames of reference, particularly when relative velocities are involved. It is a fundamental consequence of Einstein's theory of relativity.
According to special relativity, time dilation arises from the relative motion between two observers. When two observers are in relative motion, each will perceive the other's clock to be running slower compared to their own clock. This means that time appears to pass at different rates for observers in relative motion. The faster the relative velocity between the observers, the more pronounced the time dilation effect becomes.
In general relativity, time dilation is also caused by differences in gravitational fields. In the presence of a gravitational field, such as near a massive object like a planet or a black hole, time runs more slowly as the gravitational field becomes stronger. Clocks located closer to the source of gravity will tick slower than those farther away. This is known as gravitational time dilation.
Time dilation has been experimentally confirmed through various experiments, including measurements involving high-speed particles, atomic clocks, and the global positioning system (GPS). It is a crucial concept in understanding the behavior of time in different scenarios and has significant implications for our understanding of space, time, and the nature of the universe.