David VanHorn > Ok, sanity check time. I've had another one of those disturbing > thoughts. These disturbing thoughts clearly show that you are insane ... :-) > Photons travel at the speed of light, and no other speed (in a given > media). Correct? Yes. > Time slows for a particle as it approaches C, and at C a particle does > not observe time passing at all. Correct? No. Time does not appear to pass for the particle *to an outside observer*. Time passes just fine in the frame of the particle. But to the particle, time appears to stop in the rest of the universe. This is one reason that you can't actually accelerate real particles all the way to the speed of light. However, because of the expansion of the universe overall, there are objects that are moving away from us at speeds greater than the speed of light. You're right, we can't see or interact with them in any way. -- Dave Tweed -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist