Einstein's twin paradox explained
5,045,716 views | Amber Stuver • TED-Ed
On their 20th birthday, identical twin astronauts volunteer for an experiment. Terra will remain on Earth, while Stella will board a spaceship. Stella's ship will travel to visit a star that is 10 light-years away, then return to Earth. As they prepare to part ways, the twins wonder what will happen when they're reunited. Who will be older? Amber Stuver investigates the "Twin Paradox." [Directed by Aim Creative Studios, narrated by Bethany Cutmore-Scott, music by André Aires].