Assume A and B are at rest on earth initially. Then B travel to to one light year far away from earth with an extremely low speed (even slower than a car). So I can assume their ages are the same after B has arrived, right? Then, B returns to earth with an extremely fast speed (~0.9c) and A and B met at one point. Assume B does not stop, at the moment they met, who is older?(adsbygoogle = window.adsbygoogle || []).push({});

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# About twins paradox

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