According to the theory of relativity, the speed of light in a vacuum, denoted by 'c', is a fundamental constant of nature and is the maximum speed at which information or causal influences can travel. However, the concept of time moving at the speed of light for a subject at rest is not accurate.
In special relativity, time is considered as one component of spacetime, a four-dimensional framework that combines three dimensions of space with one dimension of time. The theory introduces the concept of time dilation, which means that the passage of time can be experienced differently for observers in relative motion or in different gravitational fields.
For an observer at rest, time does not move at the speed of light. Rather, time is experienced as flowing at a constant rate according to the observer's reference frame. From the perspective of an observer at rest, the speed of light remains constant and is independent of the observer's motion or location.
It is important to note that the speed of light is an absolute limit for the propagation of information or causal effects. It is not a measure of the speed at which time itself moves. Time is a fundamental aspect of our experience and is independent of the speed of light or the observer's motion.