Transcription (en)

Time Dilation You get on a ship pointed at a star a thousand light years away. It accelerates to 99.99% of the speed of light. You arrive in three years. Not three years that felt short. You aged three years. Your hair grew three years. And the clock on the wall agrees with you. Because at that speed, the distance itself shrinks. One thousand light years of space compresses to about three light years ahead of you. But behind you, nobody's space shrank. For Earth, nothing crosses one thousand light years faster than light does. The trip took just over a thousand years. Now turn around and come home. Another three years. You step off the ship six years older than the day you left. Earth is 2,000 years ahead. Everyone you have ever spoken to has been dead for around 20 centuries. Both are true. Neither of you is wrong. Time isn't a thing that passes. It's a thing that happens to you, at your own rate.