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In this 'engineer-friendly' mini-series on the famous "twin paradox" of relativity, where Pam sets off on a long, fast space journey and on return finds herself younger than her twin brother, we have viewed the situation in various ways. What we have not done yet is to view the situation strictly from Pam's frame of reference.
The problem we face is that Pam does not find herself in one inertial frame of reference for her whole trip. If we insist on drawing Pam's two phases (outbound and inbound) on one inertial frame, we are forced to insert a discontinuity in the inertial frame of brother Jim, as illustrated in figure 1 below.
Figure 1: 
The vertical line is Pam's world line, with the bullets showing the 8 years that elapsed. During Pam's acceleration for the turn-around, the lines of simultaneity change drastically in her reference frame. This causes the apparent discontinuity in the home twin's world line, showing that one should rather not represent two different inertial frames as a single line on a space-time diagram.
A much better way is to stick to one of Pam's inertial frames as the reference. In figure 2 below, I chose Pam's home bound trip as the inertial reference frame. In this frame, Pam moves at 'double speed' until her turn-around point, meaning we must do a relativistic doubling of her velocity: (0.6c+0.6c)/(1+0.62/c2) = 0.882c.
Figure 2: 
At the turnaround point, Pam decelerates until she is stationary in the reference frame and then waits for Jim to catch up. Jim is doing a steady 0.6c in the reference frame and the reunion happens 12.5 years later on the calendars of the chosen reference frame.
However, Pam and Jim again aged 8 and 10 years respectively, as before. The New Year's messages were also received just like in the previous article, because the relative Doppler shift ratios stayed the same.
Readers are urged to carefully look at Fig. 2. If one understands the reasoning behind these distances and times, you understand special relativity! You can learn more about the twin paradox in a free download from this page at the website/eBook Relativity 4 Engineers. (There's still a X-mas special on there, but time is running out...)
In the next installment on relativistic paradoxes, the "long ladder paradox" will be discussed.
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