16. •• The distance to Planet X from Earth is 1.00 lightyear.

(a) How long does it take a spaceship to reach X, according to the pilot of the spaceship, if the speed of the ship is 0.700c relative to X?

(b) How long does it take the ship to make the trip according to an astronaut already stationed on Planet X?

(c) Determine the distance between Earth and Planet X according to the pilot and according to the X-based astronaut and explain why the two answers are different.