@parados,
Quote:Until you decide the frame there is no way to tell which it is
That very mistake is implicit in the above claim of yours, and it is tantamount to utterly subjective solipsism, if I interpret it correctly.
Given the context, I take you to be saying this:
Until I, the relativist doing mathematical calculations, arbitrarily designate one of two given objects to be the stationary one (by deciding to use it's frame for purposes of calculating), BOTH are motionless.
Once I make that decision, I THEN know which one is moving.
So, if you "choose" the frame of the rocket moving to Mars, it is NOW stationary, as you "predicted?"
If you choose the earth's frame of reference, that same rocket is NOW moving?
Do you really think that your personal, subjective, and arbitrary assumptions, as they pertain to mathematical exercises, dictate reality?
Does the rocket, out there in space, "stop moving," when you make one choice, and start moving when you make another?