Carol and Charlie are two kids in their early twenties and madly in love. Charlie thinks Carol is beautiful and Carol thinks Charlie is a hunk. Now Charlie travels away from Carol at 99.99% of the speed of light. Now as we all know, traveling at that speed, time slows down, so when Charlie returns a year later, in Carol’s own eyes she has aged 50 years but Charlie is only a year older and still handsome. On the other hand, motion is relative. So from Charlie’s point of view, Carol is traveling away from him at 99.99% of the speed of light, and so time passes slower for her. So when she returns a year later, he believes he has aged a whole year, but Carol looks to him like she has aged only one week and is still beautiful. This proves Einstein’s second law of relativity: Beauty is in the eye of the beholder.
