Well firstly, I am humbled by your superior knowledge in this field <img src="/images/icons/smile.gif" /> I thought I understood the concepts, but there do seem to be problems with my understanding of time dilation and special relativity.<br /><br />I am an interested amateur, and have no formal education in these fields so I am open to anyone who can explain these things.<br /><br />Instead of making statements based on my limited understanding, I will ask questions.<br /><br />1. If time dilation is symmetric between 2 inertial observers, and they see each other sped up or slowed down by the same amount when in an inertial frame, how do they end up aging differently? Wouldn't they see the other slowed or sped up in a non symmetrical way only during the times they weren't in an inertial frame?<br /><br />2. In the atomic clocks on planes experiment, did the plane flying against the earths rotation have the same airspeed as the other plane? Or did they subtract the speed of the earths rotation from its velocity?<br /><br />3. A photon "experiences no time" during its journey, so if we could observe it during it journey towards us, would we see it "frozen in time"?<br /><br />4. If the photon could observe us as it journeyed towards us, would it see us frozen in time too? (This seems a silly question, I know!)<br /><br />5. Back to the twins paradox I'm afraid! Most (admittedly fictional) accounts of relativistic travel assume that the ship would accelerate until it reaches the halfway or turnover point, and then decelerates until it reaches it's destination (or turns round and makes the return trip). In this scenario the traveller spends very little time, if any at all, in an inertial frame during the journey. Nearly the whole journey is either accelerating, deceleration or turning round. How does this affect the time dilation?<br /><br />I wasn't trying to propose radical ideas, I thought I was saying it the way science does, but it seems I was wrong. Feel free to help me understand <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>