Final answer:
According to special relativity, an astronaut moving at a significant fraction of the speed of light relative to Earth would observe the rate of his clocks to have slowed, and see Earth-bound clocks running slower. The astronaut's ship would seem to shorten, and the distance between stars parallel to his motion would also appear shorter.
The astronaut and an Earth-bound observer would not agree on his velocity relative to Earth due to the relativity of motion.
Step-by-step explanation:
(a) Yes, the astronaut observes the rate of his clocks to have slowed. This is due to time dilation, a relativistic effect that occurs at high speeds. According to the theory of special relativity, time appears to slow down for objects moving relative to an observer.
(b) From the perspective of the astronaut, the Earth-bound clocks would appear to be running slower than his clocks. This is because the astronaut's velocity relative to the Earth affects the perception of time.
(c) Yes, the astronaut's ship seems to shorten when observed from his frame of reference. This is known as length contraction, another consequence of special relativity. Length contraction means that objects moving at high speeds appear shorter along their direction of motion.
(d) For the astronaut, the distance between stars that lie on lines parallel to his motion would appear shorter. This is also a consequence of length contraction. The distance would be contracted in the direction of the astronaut's motion.
(e) The astronaut and an Earth-bound observer would not agree on the astronaut's velocity relative to the Earth. This is because of the relativity of motion. Motion is relative, and different observers can have different measurements of velocity depending on their frames of reference.