The scenario you've described is an example of a phenomenon known as time dilation, which is a consequence of special relativity. Time dilation occurs when there is relative motion between two observers or reference frames, and it leads to a difference in the perception of time between the two frames.
In the case of the spaceship traveling at close to the speed of light, let's consider two observers: one on Earth and one on the spaceship. From the perspective of the observer on Earth, the spaceship is moving at an extremely high speed. According to special relativity, as an object approaches the speed of light, time dilation occurs, causing time to pass more slowly for the object in motion relative to a stationary observer.
So, when the spaceship travels from a distance of 1 light year away at near-light speed, the observer on Earth will perceive time on the spaceship to be passing more slowly than their own time. This means that, from the perspective of the observer on Earth, the clock on the spaceship will appear to be running slower.
On the other hand, from the perspective of the observer on the spaceship, it is they who are at rest, and it is the Earth that is moving at a high speed. Therefore, they will perceive time on Earth to be passing more slowly. As a result, from the spaceship's perspective, the clock on Earth will appear to be running slower.
This apparent contradiction is resolved when the two observers come back together and compare their clocks. The observer on Earth will find that less time has passed on the spaceship compared to their own time. Likewise, the observer on the spaceship will find that less time has passed on Earth compared to their own time. This phenomenon is known as the twin paradox.
In summary, the difference in perception of time between the two frames arises due to the relative motion between them, and it is a consequence of the principles of special relativity. It may seem counterintuitive, but it is mathematically consistent and has been confirmed by numerous experimental observations.