I've been researching relativity out of interest for a while now. I am quite fammiliar with most of the basic principals. But I have a few questions, 1)If there was a large wheel with about the same circumference of the earth, and you managed to spin in it so that the edge of the wheel was traveling at near the speed of light relative to the center (so it was spining 7rps), what effects would we see happening? And if its impossible to reach the speed of light because you'd need an infinate ammount of energy, would it therefore be impossible to make is so the inside of the wheel was turning at a speed that would insure the edge is traveling at the speed of light? 2)With the twin paradox, the twin in space ages less because of the relativistic doppler shift which relies on traveling in the right direction to work. What if you were to make that twin blast off and just travel in circles at great speeds, would we see the same effects? 3)If photons travel at the speed of light relative to everything, then shouldnt all time stop therefore making light from one source to an object instantaneus?