This is something that I have repeatedly read about, and I just cannot seem to understand it.
For those that don't know, the theory is that if you have two twins, and one gets on a ship and takes a trip at near-the-speed-of-light velocity... when they return to earth, they will have aged less than the other twin that stayed on the planet the whole time.
For purposes of discussion, I prefer the example of two identical watches that are synchronized, and one takes a similar journey as the twin mentioned above. According to the theory, when the two watches are brought back together, one should be chronologically behind the other.
Here's my problem... why is either watch affected by it's velocity? If we're talking about mechanical watches, wouldn't the gears that drive the motion of the watch continue to function appropriately regardless of where they're going or how fast they are getting there?
Furthermore, if we provide a specific frame of reference... let's say 1 earth-year... for the journey of our near-light-speed ship, wouldn't one year have passed for both watches? And therefore, shouldn't both watches reflect the same date and time when they are brough back together?
™ Version 4.2