http://en.wikipedia.org/wiki/Time_dilation
Ok, so let's take two twins, Raj and Ragan. Raj is orbiting a massive cosmological object, Ragan is on the surface. Ragan's time appears to travel slower than Raj's time.
Does FTL communication between Ragan and Raj ever create a situation where messages can travel backwards in time? Does bringing an observer into it help?
