This is a classic thought experiment relating to the Special Theory of Relativity.

Two twins of the same age start on planet Earth. Twin A stays on Earth while twin B travels far, far away and back at near the speed of light.

Because of Special Relativity, A looks at B's clock, and it moves slower than his own. So at the end of B's journey, A is much older than B.

However, B's frame of reference is equally valid. According to B, A's clock is moving slower than his own. So at the end of the journey, B is older than A.

What faulty reasoning leads to this apparent contradiction?

I think the faulty reasoning lies in the fact that twin B tries to rely on his watch. He is not aging faster than twin A. Twin A is aging faster and he knows it because his watch is still working "right". Time is manipulated by gravity, space, velocity, hmmm, too many things. Comments?

Posted by Gina Ernyey on 2006-05-26 13:15:59