The measured distance, in this case, is constant... it's the length of string between the two spaceships. And the speed of light is constant as well -- from either reference frame its c. Thus, from either reference frame (spaceship A or B) it will take 2 years for the light to make a round...
This question concerns a paradox I've come up with in GR. If somebody could tell me where it breaks down, I'd be much obliged. Thank you!
Assume there is spaceship A hovering above a black hole, and spaceship B further away from a black hole The black hole, A, and B are all lined up. (The...