E=MC2, if I understand it correctly, tells us that an object would need an infinite amount of energy and mass in order to travel at light speed, which is why particle accelerators can only travel at 99.99999 or so percent of the speed of light. With this in mind I have a couple of questions: 1) Why would you need an infinite amount of mass and energy in order to travel at a finite speed? 2) Why is it that the amount of energy and mass required to travel at 99.99999% of C is finite, but suddenly becomes infinite at 100% C? If the percentage was 99.9 followed by a billion decimals of 9, the energy and mass would obviously still be a finite number. What accounts for this sudden transition into infinity?