Time dilation refers to the phenomenon where the passage of time is experienced differently by two observers in different relative motion or different gravitational fields. The difference between the two clocks due to time dilation can be described as follows:
- Relative Velocity Time Dilation: According to the theory of relativity, when two observers are in relative motion with respect to each other, they will measure different amounts of time passing between the same two events. The observer in motion will perceive time to be passing more slowly compared to the observer at rest.
For example, imagine two synchronized clocks: one on Earth and another on a spacecraft traveling at a significant fraction of the speed of light. From the perspective of an observer on Earth, the clock on the spacecraft would appear to be running slower. This is known as time dilation due to relative velocity.
- Gravitational Time Dilation: Gravity also affects the passage of time. In the presence of a gravitational field, time runs slower for an observer in a stronger gravitational field compared to an observer in a weaker gravitational field.
For instance, if there are two clocks, one placed on the surface of a massive planet and another located in a region with weaker gravitational field (e.g., in space), the clock on the planet's surface will tick slower relative to the clock in the weaker gravitational field. This is known as gravitational time dilation.
Both relative velocity time dilation and gravitational time dilation have been experimentally verified and are crucial aspects of the theory of relativity. They have practical implications, such as the need to account for time dilation in high-precision GPS systems.
In summary, the difference between two clocks due to time dilation arises from the relative motion between observers or the difference in gravitational fields experienced by the clocks. These effects can cause measurable differences in the passage of time between observers, leading to a "dilation" or stretching of time as perceived by each observer.