Explain this common observation clearly : If you look out of the window of a fast moving train, the nearby tress, houses etc. seem to move rapidly in a direction opposite to the train's motion, but the distant objects (hill tops, the Moon, the starts etc.) seem to be stationary. (In fact, since you are aware that you are moving, these distant objects seem to move with you).

Explanation

Apparent distance moved by objects opposite to motion of train is proportional to the visual angle formed by two positions of object on our eyes. This visual angle is smaller for distant objects and thus objects very far off from observer seem stationary.