Help me out please. I need a definitive comment for a book I'm writing. Hypothetically - if Usain Bolt were to approach (c) in a 100m sprint - his mass would become infinite right? basic E=Mc2. At inifinite mass - space-time would warp (correct?). And light would bend (right?) Can I say that time will appear to slow down to an observer (spectator) watching Usain in motion? Note: I am an economist not a physicist. So please dont shoot me down if I have it wrong. Correct me. But I really need a good answer. Many thanks!