After learning more about relativity, and the vast amount of knowledge that is on this forum, I would like to clear up a few questions I had about relativity. 1) If Alice is on a planet and sees Bob fly away from her through the universe at .9c relative to her and bob then throws a baseball at .9c in the same direction he is travelling in I have a few questions; If you let each object move for 1 second relative to the object itself would you see from a fourth frame of reference; Alice, Bob, and Bob's baseball should be moving for different amounts of time relative to you as they are travelling at different speeds. If you measured the distance from Alice and Bob would it be .9ls? If you measured the distance from Bob and Bobs Baseball Would it be .9ls? If you measured the distance between Alice and Bobs Baseball would it be 1.8ls?