[Mentor's Note: Post moved into its own thread from this one] Hello, I have another newbie relativity question which is somewhat related to this topic. Here it is: There are 3 observers on 3 different planets each in a different galaxy. Observer 1 stands on the north pole of their planet looking through a telescope looking straight up from the pole and see Observer 2 moving directly away at 51% the speed of light. Observer 1 then travels to the south pole and looks through a similar telescope looking straight up from that pole (the opposite direction of the first observation) and sees Observer 3 moving directly away at 51% the speed of light. Ignoring there's a planet directly between Observer 2 & 3, could Observer 2 & 3 see each other? Or are they outside each other's observable universe? It would seem from Observer 1's point of view that they are moving away from each other faster than the speed of light.