Not right. This depends on which inertial frame you use to describe things. Since they have spatial separation, their relative age is going to depend on the inertial frame. You will find inertial frames where A is younger and you will find inertial frames where B is younger. A big problem many people are facing when learning special relativity is the underlying assumption that there actually is a well defined way of comparing the times - there is not due to the relativity of simultaneity.yykcw said:So I can assume their ages are the same after B has arrived, right?
What I don't understand is that, B should feel A is younger than him at any time during his return trip to earth, so if he does not stop, why at the point they met, to B, A suddenly becomes older?PWiz said:It is as Orodruin has pointed out. When two frames, initially co-located at some point (event, to be precise) A with their clocks synchronized meet again at point B, it is always the clock in the frame that accelerated that reads a lower time interval. This is the concept of maximum proper time (unaccelerated observers measure the greatest time interval).
yykcw said:What I don't understand is that, B should feel A is younger than him at any time during his back trip to earth, so if he does not stop, why at the point they met, to B, A suddenly becomes older?
It's not as simple. In the first half of the journey (when person B is moving away from person A at constant velocity), both A and B see the other person as younger. This is the relativity of simultaneity, an inescapable consequence of the fact that time is not absolute. (No one is justified in saying who's older [or conversely, both of them are justified in saying that the other one is older] because we can't make a direct comparison until A and B are side by side again.) However, B cannot return to A without changing direction, and this means that B has to accelerate, so the situation is no longer symmetrical (acceleration breaks the symmetry because it means B is instantaneously changing inertial frames until B finally "settles" into a new inertial frame after changing the direction and speed to the required levels). Since B's rest frame is now a different frame compared to what B was initially going in during the first part of the journey, there is a different relation between this new frame and A's rest frame, and there is a disparity in the elapsed time for A and B.yykcw said:What I don't understand is that, B should feel A is younger than him at any time during his return trip to earth, so if he does not stop, why at the point they met, to B, A suddenly becomes older?
PWiz said:However, B cannot return to A without changing direction, and this means that B has to accelerate, so the situation is no longer symmetrical (acceleration breaks the symmetry because it means B is instantaneously changing inertial frames until B finally "settles" into a new inertial frame after changing the direction and speed to the required levels).
yykcw said:Assume A and B are at rest on Earth initially. Then B travel to to one light year far away from Earth with an extremely low speed (even slower than a car). So I can assume their ages are the same after B has arrived, right?
Then, B returns to Earth with an extremely fast speed (~0.9c) and A and B met at one point.
The Twin's Paradox is a thought experiment in physics that involves two identical twins, A and B. Twin A stays on Earth while Twin B travels through space at high speeds and then returns. According to the theory of relativity, time will pass at a different rate for each twin, resulting in one twin being older than the other.
It may seem counterintuitive, but according to the Twin's Paradox, Twin B will be younger than Twin A upon their return. This is because time will have slowed down for Twin B due to their high-speed travel, while time will have passed normally for Twin A.
While the Twin's Paradox is a theoretical concept, it has been experimentally verified through the use of atomic clocks. In fact, astronauts on the International Space Station experience this phenomenon to a small degree due to their high speeds in orbit.
Yes, the Twin's Paradox is a result of the theory of relativity, specifically the concept of time dilation. According to this theory, as an object's velocity increases, time will pass more slowly for that object compared to a stationary observer.
While the Twin's Paradox may seem like a purely theoretical concept, it has real-world applications in fields such as space travel and GPS technology. Understanding time dilation is essential for accurate GPS calculations, as the satellites used in GPS systems are traveling at high speeds in orbit.