Hi, In the often cited example of a person in a rocket traveling past Earth at high speed - I think I understand that both the person on earth and on the rocket could view the other as being the party that's actually moving. And so if they could view the other party, they would both see the other moving in slow motion. And I guess there is an assumption that time is relative to the observer. So if the rocket travels 10 years at speed near c, and then turns and spends another 10 years getting back to Earth, those 20 years in space may reflect say 100 years on earth. The original earth person will be 100+ years old, and the space-person 20+ years old. But if time were relative to the other originally, now it seems that Earth time has become an absolute reference frame. I feel like I'm totally comparing apples and oranges, but can't figure out why. Does this make sense (my question)?