I'm having some trouble relating the twin paradox with the idea of relativity (from a lay, conceptual perspective), and I was hoping someone could clear it up for me. It seems from reading the Wiki page that the paradox is resolved because of the asymmetry of the inertial reference frames of the twin on Earth relative to the traveling twin. The page states, "Here the Earth and the ship are not in a symmetrical relationship: the ship has a turnaround in which it undergoes non-inertial motion, while the Earth has no such turnaround. Since there is no symmetry, it is not paradoxical if one twin is younger than the other. I have twin trouble with this explanation. First, it seems to state on its face that acceleration is a special condition that seems to usurp the idea of relativity at all existing between one twin and the other. Is the idea of relativity then constrained to the Special condition? What is meant by general relativity if relativity is not really relative between non-inertial or accelerated frames. My second trouble relates to this statement on the wiki page, "Special relativity does not claim that all observers are equivalent, only that all observers at rest in inertial reference frames are equivalent. But the space ship jumps frames (accelerates) when it performs a U-turn. In contrast, the twin who stays at Earth remains in the same inertial frame for the whole duration of his brother's flight. No accelerating or decelerating forces apply to the twin on Earth." Doesn't the Earth go through a centrifugal acceleration due to its rotation? Sure, its not .8c, but it qualifies as an accelerating force. In any case, I'm not an expert on relativity and I'm sure some consensus has been acheived on what is happening here. Please explain it to me like I'm a 4 year old so I can understand it. Thanks!