A spaceship flies past Mars with a speed of 0.985c relative to the surface of the planet. When the spaceship is directly overhead, a signal light on the Martian surface blinks on and then off. An observer on Mars measures that the signal light was on for 75.0µ.s.
(a) Does the observer on Mars or the pilot on the spaceship measure the proper time?
(b) What is the duration of the light pulse measured by the pilot of the spaceship?