User blog comment:Chormira the Autobot/Who's the Fastest?/@comment-24463386-20110828170423/@comment-115265-20110829021719

@ Wikia Contributor: In reality, as far as we have gotten in technology, yes, going faster than light is indeed impossible. But, then again, Sonic is fiction. Science fiction and Fantasy, rolled into one. He can't go faster than light as Normal Sonic, but Super and Hyper Sonic can.

Sonic has been seen going at light speed, though... It's called Light Dash/Lightspeed Dash, and Lightspeed Attack.