I dont feel like really explaining it anymore because you guys just seem to be out there to ask questions that dont actually really apply here in any way.

Here is a video explaining everything.
Its math but if you are willing you can understand it.
AND PLEASE STOP ADDING NEWTON PHYSICS INTO THIS DISCUSSION THEY DONT FIT HERE

The interesting thing is that when you write down how much time the traveling twin is rewarded by when accelerating, it turns out to also depend on the distance between them. So since the distance appears in the formula, the amount of time spent traveling apart matters and your original intuition is correct.

There may seem to be another contradiction here: if acceleration is the key to explain why one twin really ends up being younger, and acceleration is a 'local' effect, why does the distance between twins when the traveling twin turns around matter?

This last 'contradiction' can be cleared up by accepting that time and space are not separate entities. They are related and one is clearly affecting the other in this example. This is different than our intuition and every day experience would suggest, and thought must put into this (and excellent questions are being asked here).

Ulim, the discussion began when you made certain claims:


This is in direct contradiction with the video you posted, did you even watch the video? Skip ahead to 18:00 if you don't believe me. The video points out that both observers make equal observations about the other party.

Here is another video, that actually does address the twin paradox:


Pay close attention to this quote from the end of the video (at 2:45):

As it was stated before, the crux of the issue is the acceleration, not the motion.

Perhaps the discussion turned into nitpicking, but that is what happens when you avoid the questions and instead resort to accusing others of confusing relativity with newtonian physics, while not even properly understanding orbital motion yourself.

If you got at c speed you dont experience time. Time is frozen for you..

Ye my bad I forgot that this happends due to doppler effect

Yes, I think there would be a relativistic Doppler effect in the circular motion example. One disclaimer: I don't remember the spinning example from my general relativity grad courses (we jumped right into tensor analysis ) so I could be wrong in this example but here are my thoughts.

The twin moving in circles is experiencing an acceleration as Pitubo pointed out. A practical example of this is NASA training astronauts for the large take off accelerations by spinning them around in a training chamber. From the point of view of the spinning twin if feels like they are in a high gravity environment being pushed against the back wall. If they shine light "upwards" towards their twin, it will be Doppler shifted (just like any light coming out of a gravity well). From the spinning twin's point of view, time is moving slower because they are deeper in a gravity well.

So in the spinning example, both twins would measure time going more slowly for the spinning twin. This is very different from the situation when the twins are moving apart at a constant speed where they both observe the other twin's time moving more slowly than theirs.

When I get home I can do some calculations and will update this post if I can figure out that I'm wrong. I'm getting a time dilation factor of 1+gD/c^2, where g is the acceleration the spinning twin feels against the back wall and D is the distance between then (again, the distance between them comes into play when considering acceleration itself).