The experiment showing that, time is relative, and how it changes with velocity and gravity. Einstein's twin experiment. One twin stays on earth while the other flies for 5 years at some velocity near the speed of light. let's say he travels at .8c. he then turns around and travels at .8c back to earth. when he gets back, he will find that he has aged 10 years, but is brother has aged significantly more. If they both had telescopes and could watch each other during this trip, then the twin on earth would see his twin moving in slow motion, while the one on the ship would see his bro moving really fast. Has there been very much more research done with this experiment? And, Has it actually been proven, most importantly, can it or will it ever be applied or used for much of anything? Do we have the capacity to do so?