A rocket leaves earth at speed 0.80c on its way to a planet a distance 20ly as measured by earth. When the rocket gets to the planet it sends a light signal to earth.
a. a When does the signal get to earth according to (i) earth and (ii) rocket?
b. b Illustrate your answers with a spacetime diagram.
c. c At t=0, another rocket leaves the planet returning to earth with speed 0.80c relative to earth. As the rocket sets out it sends a light signal to earth. When does the light signal arrive at earth according to (i) earth and (ii) rocket clocks?
d. d Illustrate your answers on a spacetime diagram.