Sorry for interrupting,but i feel the twin paradox will always appear to me invalid.Because the twin accelerating at C always stops and accelerates back.Which gives us a frame of ref for each simultaneous.I think laws of physics would be violated.
As an example i offer this.
The universe is approx 14.5 billion years old,so if we had a telescope capable of allowing us to see say 14.49 by then we must calculate the light we see has taken 14.49by to reach us.Therefore we assume a correct age,however IF a person travelled at LS from secs after the big bang upon reaching earth his time frame would be a younger universe.Which is invalid because then we would say depending on ones Frame of reference the universe has no calcuble age.
A thought ,from our own frame of reference we acknowledge we are not at the edges of the expanding universe,and whichever direction we care to view,the universe expands before us.So how can we give a definitive age for an infinite universe.
I presume i may not have this correct,but unless we can pinpoint our exact location in space time,our physics will always fail when calculating such.Im comfortable it being our best guess but not our arrogant affirmation.
Please help me out here if im wrong.