The concept you're referring to is related to the fundamental principles of relativity, as described by Albert Einstein's theory of general relativity. In general relativity, space and time are intricately connected, forming a four-dimensional fabric called spacetime.
In spacetime, objects can have various trajectories, which can involve both movement through space and through time. An object can be at rest in space while still experiencing the passage of time. This phenomenon is commonly referred to as time dilation.
Time dilation occurs due to the influence of gravity or when an object is moving at high speeds relative to an observer. When an object is in a gravitational field or experiences significant acceleration, it can cause the flow of time to differ between two observers, depending on their relative positions and motion.
To illustrate this concept, consider a scenario where an astronaut is floating in space near a massive celestial body, such as a planet. The gravitational field of the planet will affect the astronaut's experience of time. From the perspective of an observer far away from the planet, the astronaut's time will appear to pass slower compared to their own. However, from the astronaut's perspective, they will experience time passing at a normal rate.
In this situation, the astronaut can be stationary in space (not undergoing any motion in the traditional sense) but still experience the flow of time. The presence of a gravitational field can influence the passage of time without requiring the astronaut to move through space.
So, the key idea is that in the framework of general relativity, an object's motion through time and its motion through space are interconnected, and the effects of gravity and high velocities can cause time dilation, allowing an object to experience the passage of time while being at rest in space.