Is there some location, object, or
that FE is accelerating in relation to? How can I know about what is outside the FE/dome system? If astronomical objects are part of the dome, or on it, or whatever, then the dome is accelerating right along with FE. What is it that is not part of FE and dome that we are accelerating in relation to? How do we know where FE+dome is, or what it is moving in relationship to? Zetetically, can I believe there even is any movement until I can see or somehow know the thing or location FE is accelerating in relation to? If we can't know about anything outside the FE/dome system? Does UA demolish the "infinite plane" idea, could an infinite plane accelerate, having infinite mass?
Or maybe astronomical objects are not accelerating with FE? How do I know where they are?
When I drop something and it accelerates towards the floor, is that object continuing ti travel at the velocity FE was at when I dropped it and the entire FE/dome system continues to accelerate?Is this the only way I know the whole system is accelerating?