On 4/26/12 3:30 PM, Koobee Wublee wrote some nonsense which I
choose no to replicate.


http://www.phys.vt.edu/~takeuchi/rel...notes/twin.gif

Changing direction involves *acceleration* which puts the astronaut
in a *non-inertial frame*.

Virginia Tech College of Science Physics Dept Tatsu Takeuchi Special Relativity Lecture Notes Section 15
http://www.phys.vt.edu/~takeuchi/rel...section15.html