A spacecraft leaves earth moving away at speed relative to earth
PHYSICS · Subjective · A Level · Physics · Turning points in physics · Turning points in physics
Problem
A spacecraft leaves earth moving away at speed 0.60c relative to earth. Mandy, an astronaut, has her birthday that day. In a year's time (according to spacecraft clocks) she will have her birthday again. Her friends on earth want to celebrate by sending her a light signal. When, by earth clocks, should the light signal be sent so that it arrives at the spacecraft on Mandy's birthday?