The phenomenon of time dilation occurs as a consequence of the theory of special relativity, proposed by Albert Einstein in 1905. According to special relativity, the speed of light in a vacuum is constant and is the same for all observers, regardless of their relative motion. The theory also states that the laws of physics should be the same in all inertial reference frames.
When an object moves relative to an observer at a significant fraction of the speed of light, the observer will perceive time passing differently for the moving object compared to their own reference frame. From the perspective of the moving object, time appears to pass at its normal rate. However, from the perspective of the stationary observer, time appears to slow down for the moving object.
This phenomenon can be explained by the concept of spacetime. Special relativity introduces the idea that space and time are not separate entities but are unified into a four-dimensional structure called spacetime. Spacetime is a framework in which events and their order of occurrence are described.
As an object accelerates and approaches the speed of light, its motion through spacetime affects the perception of time. When an object moves rapidly, its motion through space affects the flow of time relative to a stationary observer. This effect is known as time dilation.
From the perspective of the moving object, it is at rest within its own reference frame, and time appears to pass normally. However, from the perspective of the stationary observer, the moving object is covering a greater distance through space in a given amount of time. As a result, time appears to slow down for the moving object relative to the observer's own reference frame.
This phenomenon arises due to the invariance of the speed of light in special relativity. As an object's velocity approaches the speed of light, its relative motion through spacetime causes time dilation. This effect has been experimentally confirmed and is crucial in understanding the behavior of high-speed particles and the operation of systems such as GPS satellites, which require corrections for the time dilation effects of their high velocities relative to Earth.
In summary, time dilation occurs because the motion of an object through spacetime affects the flow of time relative to a stationary observer, and this effect arises from the invariance of the speed of light in special relativity.