I'm curious about time dilation sizes of below 4 situations. Please assume I'm observing the situations far away in zero gravity. And please ignore all SR effects, just focus on GR. http://dishdev.me/data/timedilationq.png [Broken] Equivalence Principle says acceleration and gravitational fields can substitute for each other. I also learned a time dilation by GR occurs in gravitational fields and accelerating frames, and I can interpret the time dilation by any of the two concepts. But I'm confused by situations when acceleration and gravity both exist. The clock in A has a plain orbital motion. The clock in B also has the same orbital motion but it's caused by artificial propulsion directed to the center of this rotational motion, not by gravity of the heavy star. Do both clocks have the same time dilations because of the same accelerations they have? Or the clock in A has more time dilation by gravitational field of the heavy star? The clock in C has no movement at all because it cancels the gravity by the same size propulsion. It also has no apparent acceleration. Does it have the same time dilation as the clock in A? Or smaller because it doesn't have acceleration? In final D, the clock is on the center of two heavy stars, the spot where sizes of two gravity are exactly the same. Does it have no time dilation like observer in zero gravity space? Or more time dilation than a clock on gravitational field of one heavy star?