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ersa17

- 13

- 2

Suppose, A and B are twins where A is at the Earth, and B is moving on a spacecraft at a speed near to the speed of light. In this scenario, since there is a relative motion between two, time moves slower for the other observer with respect to own frame(i.e. For A, time slows down for B and vice-versa). But the twin paradox says that the twin who makes a trip with high speed and returns back to the Earth seems younger than the twin who is at the Earth. If A and B both see time slowing for each other, why is that only B is younger? Since B sees that time is slowing down for A, shouldn't A be the one who is younger(in B's frame of reference)?

Also, does the direction of speed have any effect on the time dilation(i.e. if moving towards or away from the observer)?