According to the theory of relativity, as an object approaches the speed of light, time dilation occurs, meaning time appears to slow down for that object relative to a stationary observer. This phenomenon is a consequence of the fundamental principles of spacetime.
However, from the perspective of the object moving near the speed of light, it would not perceive time as slowing down for itself. This is because any change in the passage of time would be relative to the observer's frame of reference. To the moving object, its own time would still appear to flow normally, and it would perceive external events occurring at a normal rate.
In other words, from the perspective of someone on a spacecraft traveling close to the speed of light, their onboard clocks would tick at a normal rate. They would not personally experience time slowing down. It is only when they compare their measurements with a stationary observer's measurements that they would observe a time dilation effect.
This concept is known as the relativity of simultaneity, where events that are simultaneous for one observer may not be simultaneous for another observer in a different reference frame. The perception of time is relative and depends on the observer's motion and relative velocity.
It's worth noting that these effects become more pronounced as an object's velocity approaches the speed of light, but they are not noticeable in everyday experiences at typical speeds. They are more relevant in the realm of high-speed particles or space travel at significant fractions of the speed of light.