Ok thanks a lot for the explanations :) I understand now.
So "proper" accelleration is always at the point where momentum would be bieng conserved. Thinking about it, spaceship 2 would be magically gaining momentum.
So why does only one feel a force, when technically they are both accelerating towards each other.
What defines who will feel the force when you have two things accelerating towards each other?
Is it to do with "how" they are accelerating?
Well I've just been learning about special relativity, and I think I understand everything I need to know, except frames of reference (for A level). I need to know where you are allowed to take frames of reference from, and where you are not.
I understand that you can't take a frame of...