Uploaded January 2019 | Updated September 2026, 1 day ago
One of the more famous supposed paradoxes in special relativity is known as the twin paradox. Time dilation tells us that moving observers age slower than stationary observers. The issue comes from the fact that (inertial) observers in special relativity always feel like they are stationary, so how do we tell the difference between who is moving and who is staying still? For this, we have to use the Lorentz transformation to show that one of our observers is not truly an inertial observer and therefore had to travel in two different directions.
One of the more famous supposed paradoxes in special relativity is known as the twin paradox. Time dilation tells us that moving observers age slower than stationary observers. The issue comes from the fact that (inertial) observers in special relativity always feel like they are stationary, so how do we tell the difference between who is moving and who is staying still? For this, we have to use the Lorentz transformation to show that one of our observers is not truly an inertial observer and therefore had to travel in two different directions.
