Triplets paradox when circling in opposite directions on a rotating Earth Spaceman Spiff travels around the equator westward, and Spaceman Spoof travels around the equator eastward, while Earthman Spud just hangs out on his couch. If there is no privileged frame of rest, then the Earth's rotation relative to the solar system or to the cosmic microwave background must be irrelevant. Right? So, when they meet at Spud's Place for beer, whose atomic watch will show faster or slower times elapsed?
Does the equal energy spiff and spoof use make their clocks identically slower than Spud's? Afterall, they are all moving in circles relative to each other, so directions of movement should be irrelevant I would think. I apologize if these questions have been asked before. I would be grateful for an explanation in lay terms. Thanks.
 A: Here's an explanation in lay terms as requested. Firstly, special relativity is counter-intuitive, and most people have to puzzle over it for a long time before the penny finally drops, so don't expect an answer on this website to make everything crystal clear. Secondly, the effects arising from circular motion in special relativity are even more counter intuitive, so I suggest you consider a simplified case as follows. Suppose Spiff and Spoof head off east and west to equally distant stars, turn around and come back to Spud who has just been coasting through space the whole time. Assuming they each accelerated at the same rate relative to Spud, when they get back to Spud each of their watches will have lost the same amount of time relative to Spud's. That gives you the general idea. If you want a rigorous analysis in the case in which all three are in circular motion at different rates around different axes then you are in for a lot of hard maths which is definitely not going to be understandable by a lay-person.
