I like a to ask a very simple question. I have read about time-dilation when it comes to SR. So, like: (1.) A and B are are rest and close to each other. (2.) B starts travelling at .5C relative to A, away from A, in a straight line. (3.) B comes back at .5C towards A. Now, according to SR, A has aged, and B has not (or aged less). My question is, will this work, even for angular velocity? i.e. (1.) A and B are millions of miles apart. Say, A is on Earth, and B is at a distance 100 times that of the moon. i.e. B is at a distance, 100 times the distance between the earth and moon. (b.) Now, B starts travelling at .5C, but with an angular velocity relative to A. i.e. A is the center, B is rotating around A an angular velocity of .5C. Now, will the time dilation effects of SR happen in this instance also?? Will the clock in B, tick slower, than the clock A has? Or, does SR apply only if B travels away or towards A in a straight line?