Consider two people born on Earth at the same time (like twins). Alice gets on a spaceship and travels to Alpha Centauri, 4.4 light years away, and back at an average velocity of 0.5c. Bob (her fraternal twin, I guess) stays on Earth. Who is older when they reunite?
Consider two people born on Earth at the same time (like twins).
Alice gets on a spaceship and travels to Alpha Centauri, 4.4 light years away, and back at an average velocity of 0.5c. Bob (her fraternal twin, I guess) stays on Earth. Who is older when they reunite?