In special relativity, time dilation occurs for objects that are moving relative to an observer at a significant fraction of the speed of light. The speed of light itself is always constant in a vacuum, but the perception of time can change depending on the relative motion between observers.
According to the theory of special relativity, as an object moves faster and faster, its relative velocity causes time to pass more slowly for that object compared to a stationary observer. This effect is known as time dilation.
To understand this concept, let's consider an example: Imagine two observers, one stationary on Earth and another traveling in a spacecraft moving at a significant fraction of the speed of light. From the perspective of the observer on Earth, time would appear to pass normally. However, from the perspective of the observer in the spacecraft, time would appear to slow down.
This time dilation occurs because the speed of light is constant for all observers, regardless of their relative motion. The theory of special relativity introduces the idea that both space and time are part of a unified four-dimensional fabric called spacetime. When an object moves through spacetime at high speeds, it experiences a distortion in the fabric of spacetime, affecting the perception of time.
The phenomenon can be mathematically described using the Lorentz transformation equations, which provide a relationship between the time experienced by a moving object (proper time) and the time measured by a stationary observer (coordinate time). These equations incorporate the factor of time dilation and show that the proper time experienced by the moving object is shorter than the coordinate time measured by the stationary observer.
It's important to note that time dilation effects become more pronounced as an object's velocity approaches the speed of light. At everyday speeds, such as those encountered in our daily lives, these effects are negligible and not noticeable. However, at speeds close to the speed of light, time dilation becomes significant and has been confirmed through experiments with high-speed particles and atomic clocks on fast-moving spacecraft.