Originally posted by LW Sleeth
I am going to question you further, not because I necessarily disagree, but because I do not yet believe what I am asking you answered.
First, let me be certain I understand your interpretation. When you say there is no difference in time rate to notice, are you saying that time has not been constricted for the traveling twin during the journey? It is "space-time" is it not that has been altered?
If time is not an issue, then how can it be the traveling twin finds his brother 35 years more aged than himself?
Let's break it down into what is measured from each frame.
Earth twin:
He sees his brother accelerate up to some large fraction of c Relative to himself and then coast. As a result, he sees his brother's time rate as running slower than his own. After coasting for some distance(Let's say to Alpha Centauri), his brother decelerates, and comes to a stop relative to him (the Earth twin). The space twin then accelerates back towards Earth, Coasts again, and then decelerates to a stop again next to him again.
According to the Earth twin, his brother's clock should show less elapsed time and his brother should have aged less than him, because of the large relative velocity difference between them during the majority of the trip.
Space twin:
His sees the Earth accelerate away from himself, while Alpha Centauri accelerates towards him. He also notes that there is a g-force acting on everything in the ship, acting in the same direction as the Earth and Alpha Centauri are Accelerating, and with a force that equals the rate of that acceleration.
This can be explain in two ways, that he is accelerating towards Alpha C, Or, He is standing still in a uniform Gravitational Field, and Earth and Alpha C are falling in it. Either assumption will give the same result because of the Equivalence Principle (equating Accleration and Gravitation), So we will use the second interpretation, as it allows us to treat the space twin as "fixed" frame of reference".
Therfore the Space twin sees the Earth fall away from him and Alpha Centauri fall towards him. As a result, he wil see the combination of two effects on his brother's time rate; one due to the Earth's increasing relative velocity, and one due to the Earth's position in the gravity field. Since Clocks lower in a gravity field will appear to run slower as measured form a frame higher in that field, he will see his Earth twin's brother's time rate as running slower. This is compounded by the fact that the Earth has an increasing Relative velocity, which will also decrease its time rate.
The g field leaves ( This corresponds with what the Earth twin sees as the "coasting" period.) Earth and Alpha C. now maintain a constant relative velocity with respect to him. He will see the time rate on Earth as running slower than his. He also will see length contraction in both the Earth, Alpha C
and the distance between them (Earth and Alpha C are just two points in the same frame that is moving relative to him.) It will take some time (t) for this frame to go from The Earth being near to Alpha C being Near. This time will be shorter than that measured by his Earth Brother during this same period. (His Earth brother see him (travel 4.3 ly at a given speed taking a certain time. He sees Earth and Alpha C Fly by him at the Same speed, measures the Distance between them as less than 4.3 ly, thus the transit takes less time.
The g field returns, but this time it points the other direction. (Earth is now Higher in the Field.) But not only is Earth now higher in the Field, it is much higher than it was lower earlier.(He is close to Alpha C and Far from Earth) The Earth's time rate will now be measured as running faster than his own (much faster than it was running slower before.) Fast enough, that by the time the g field leaves again and the Earth and Alpha C are once again at rest relative to him, all the time he saw it losing during the other periods are made up, plus some. This "plus some" will be exactly the amount that the Earth twin will have seen as due to the Space twin's time rate moving slower.
The second half (That where the Earth returns to being next to him) will be just a mirror image of the first.
Meaning that when the twins are re-united they agree as to which twin has aged the least(or most) and by how much, but not as to why. By each twin's frame the time difference is due to the combinations of length contractions and time dilations
his brother went through.