Time dilation is a phenomenon predicted by Einstein's theory of relativity, which states that time can appear to pass differently for objects in relative motion. When an object approaches the speed of light, time dilation becomes significant, and the effects become noticeable.
As an object accelerates and approaches the speed of light, time for that object appears to slow down from the perspective of a stationary observer. This means that clocks on the moving object will appear to tick slower compared to identical clocks at rest.
Additionally, the effect of time dilation is not limited to the moving object itself but also affects objects in its vicinity. Suppose there are two objects in relative motion, one moving close to the speed of light relative to the other. In that case, time dilation will cause time to pass more slowly for the object moving at high speed relative to the stationary object.
For example, let's say there is a spaceship traveling at a significant fraction of the speed of light. Clocks on the spaceship will appear to tick slower compared to identical clocks on Earth, from the perspective of an observer on Earth. If there were other objects near the spaceship, their time would also be affected, and they would experience time passing more slowly.
This time dilation effect near an object moving close to the speed of light has been experimentally confirmed and is an essential aspect of relativity theory. It leads to various interesting consequences, such as the twin paradox, where one twin traveling at high speed ages less than the other twin who remains on Earth.
It's important to note that time dilation is a relative effect. An observer on the moving object will not perceive any change in their local time; it's only when comparing it to a different reference frame that the time dilation becomes apparent.