Suppose you have two people who are in identical orbits around a large star. The only difference between them is the direction they are traveling. At a certain point where they meet ( there are two such points ), they sync clocks. After a few orbits, they meet again and again compare clocks. From "A" perspective, they don't move but instead are in perpetual free fall, while "B" moves rapidly around the star. Ditto but reversed for B. Both experience the exact same acceleration during our experiment, so who's clock is right when they compare them again? Both would expect the other's clock to run slower since, from their own perspective, the other is moving while they stand still. How is this paradox actually resolved in relativity? Also, if the universe is closed ( spatially ), then one could create the same experiment but without any acceleration at all. The twins would compare notes after passing each other again once they've lapped all the way around the universe. How does relativity resolve that paradox?