An Introduction to Modern Astrophysics · Problem 4.7
The Interaction of Light and Matter — Carroll & Ostlie
Physics — Astrophysics · twin-paradox-doppler
Problem
Upon reaching α Centauri, the starship in Problem 4.6 immediately reverses direction and travels back to Earth at a speed of u/c=0.8. (Assume that the turnaround itself takes zero time.) Both Earth and the starship continue to emit radio signals at 6-month intervals, as measured by their respective clocks. Make a table for the entire trip showing at what times Earth receives the signals from the starship. Do the same for the times when the starship receives the signals from Earth. Thus an Earth observer and the starship pilot will agree that the pilot has aged 4 years less than the Earth observer during the round-trip voyage to α Centauri.