stormgren wrote:22/7 wrote:The twins experiment has to do with an object (or person) moving at nearly the speed of light and the effects that that difference in velocity will have on that object (or person). I don't believe that acceleration comes into play, but rather relative velocities.
But the "paradox" comes from the fact that the now-younger (the one that left and came back) could claim by the equivalence principle that he was the one who stayed still, while everything else moved away from him and his ship and then came back. So, he asks, why is he younger while his brother has aged?
This is resolved by the fact that the travelling twin accelerated and decelerated. The reference frames are not always equivalent, and the travelling twin's frame isn't always inertial. Therefore he can't make such a claim.
Sure, but when you're designing something based on whether or not it accelerating, you're assuming an inertial reference frame, since we're never approaching the speed of light. So arguing that it's not provable whether or not the feather is accelerating is kind of pointless, and if you start looking at all such situations in the same light (is that person actually turning left? can I prove that?) then you'll never do anything.