I am new to the forums so hello everyone. I have spent time trying to understand the twin paradox, and I have only partially grasped it. What I specifically don't grasp is....what really happens when the traveler changes inertial frames from leaving Earth to heading towards Earth? I know the symmetry is broken at this point. The traveler can say the Earth's time is slower than his but when he changes inertial frames to heading towards Earth, he realizes that the Earth has already aged tremendously as he heads back. Maybe someone here can clarify clearly what happens when the traveler changes inertial frames that causes so much time on Earth to pass.