Castor and Pollux, identical twins, get into their individual spaceships and blast off simultaneously. Castor's is the faster ship, and both return to Earth simultaneously. Which of the following statements is true?
A) Castor is older only if he traveled in the same direction as Pollux.
B) Castor is older only if he traveled in the opposite direction to Pollux.
C) Pollux is older only if he traveled in the same direction as Castor.
D) Pollux is older only if he traveled in the opposite direction to Castor.
E) Pollux is older.

Question

Quizplus · Accepted Answer

According to the theory of relativity, the twin who travels at a higher speed (Castor) will age more slowly than the twin who travels at a lower speed (Pollux). Therefore, Pollux will be older when they return to Earth.

Castor and Pollux, Identical Twins, Get into Their Individual Spaceships