THE TWIN PARADOX
The Twin Paradox, sometimes referred to as the Clock Paradox, is frequently used as an attempt to illustrate an error with special relativity. In SR, two frames in motion relative to each other are in a sense equivalent, or symmetrical. Viewing the other from either one requires the same transformation of time and length. Thus time and distances on B viewed from A should be exactly the same as those on A viewed from B.
Therefore, because of this symmetry, if one member of a set of twins takes a ride on a spaceship then he/she should not gain or lose any time relative to the other twin.
Not so.
See complete posting: TWIN PARADOX
