Time dilation can indeed affect watches and their measurement of time. The effects of time dilation are not noticeable in everyday life or with ordinary timekeeping devices like wristwatches, but they become significant in extreme circumstances involving high speeds or strong gravitational fields.
Let's consider two scenarios: time dilation due to relative motion and time dilation due to gravity.
- Time Dilation due to Relative Motion: According to special relativity, when an object is moving relative to an observer, time appears to pass more slowly for the moving object. This effect is known as time dilation due to relative velocity.
If you have two highly precise synchronized watches, and you send one on a high-speed journey while keeping the other with you, upon reuniting, you would find that the watch that experienced high-speed travel has ticked fewer times compared to the stationary watch. This means that the moving watch has experienced less elapsed time.
- Time Dilation due to Gravity: In the theory of general relativity, gravity causes time to run slower in stronger gravitational fields. This effect is known as gravitational time dilation.
If you were to take one of your precise watches and place it in a strong gravitational field, such as near a massive object like a black hole, time would appear to run slower for the watch. When you retrieve the watch and compare it to another watch that remained in a weaker gravitational field (e.g., on Earth), the watch from the stronger gravitational field would have measured less elapsed time.
It's important to note that the effects of time dilation due to relative motion and gravity are very small under typical circumstances. They become noticeable only in extreme conditions involving significant speeds or strong gravitational fields.
In practical terms, the impact of time dilation on everyday watches or timekeeping devices we use is negligible and not something we need to account for in our daily lives. However, precise timekeeping and navigation systems, such as those used in satellites and GPS, do need to take into account the effects of time dilation to maintain accurate synchronization and positioning.