Life "c" and the pursuit of an accurate distance measurement Having trouble trying to wrap my mind around how two reference frames (both in motion) can observe a third reference frame (object at rest wrt A & B observers) and calculate the correct distance to that object. To try and keep it simple (which is about my level of understanding) I suggest the following: Three objects are in orbit around a star (A, B, C). Object A is an emerging civilization who who must calculate distance properly in order to understand the universe as is object C. B is an object at rest wrt A & B. Object A is the innermost planet with simple circular orbit. Object C is the outermost planet with a retrograde simple circular orbit. Object A & B are traveling at the same speed wrt to C in opposite directions, thus both are approaching C at the same speed. Object B is a planet in a simple circular geosynchronous orbit. The setup is this: Both A & B are approaching object C. While both A & C are at the same distance from C they both take a light measurement of object C at the same time from the point of view of an omnipotent observer. A & B are not equal, however. The subjective time of object A is .5t wrt B which is = to 1t. Object C is 2 light minutes away, at time of measurement, from both A & B. So, B measures the distance to be 2 light minutes away and A measures the distance to be (edit) '1' should be '4' (/edit) light minute(s) away? How do these two frames of reference agree, assuming that the difference in subjective time is due to the respective gravitation of A & B? Is there a way for both A & B to correct their observational measure so they can arrive at a mutually agreeable or universal distance?