What is the “Twin Paradox” in Physics?
Mary-Kate and Ashley Olsen are chosen by NASA for a highly unethical experiment that no IRB on the planet would approve. Mary-Kate is sent out in space in a spaceship that approaches the speed of light. Let’s say it’s 80% the speed of light, and is going to a planet 16 light years away. Ashley stays on earth. So Mary-Kate’s ship will take 20 earth years to do the trip (at 80% light speed), but since she was traveling so close to light speed she experienced something called “time dilation,” where she only experiences 12 years of time. She only aged 12 years and ate 12 years worth of food and her clock on her spaceship says 12 years have passed. But when she gets back to earth, she is 8 years younger than Ashley.
Basically, Mary-Kate’s body measured space-time differently as she approached the speed of light. It measured time more slowly than Ashley’s body, according to Ashley’s earth clocks.
