My teacher lectured on time dilation today and I'm confused about some things he said. How does light maintain the 2.99X108 m/s? And for that matter, what propels it to move that fast in the first place? Finally, why, as the c is approached, does the mass of an object get infinitely large? I know these may sound like some basic questions, but I didn't think they belonged with the Homework Forum. Thanks.