You live in the past. For every possible combination of sensory input you can have, there is some appreciable time between signal and interpretation. Light hits your eye or a sound hits your ear and milliseconds later you actually perceive light or sound. Right now you are looking at this screen as it was a few milliseconds in the past. Reality is on a delay. For you, nothing is now. Realizing this fact is unsettling. If we can only react to the past, how do we manage to navigate the present? It's easy to spiral into a treatise on free will while in the fetal position, overthinking our forever past. Unless you are The Flash. The Flash is the fastest man, biped, anything. He can sprint at the speed of light. When he does, Einstein rests happily in his grave. The Flash tests and proves relativity every time he decides to burn latex. No matter what speed the red blur appears to observers, time effectively stands still for the crimson superhero. But such power poses a problem. When you move that fast, you see bunch light together and change as you move--like how moving towards or away from a police car can make it sound louder or softer. The world would turn blue as you rush towards it. All light would appear to be at a higher frequency--a blue shift. (The same effect is why hyper-speed in Star Wars actually a looks more like a blur than streaking lights and why galaxies moving away from us appear redder than they otherwise should.) Being the fastest thing alive isn't very useful if vision blurs into blue obscurity when you travel. Of course, The Flash has a way around this--he lives closer to the present than any human. He can process information and even think at the speed of light. Taken from Superman #709 and infused with some scienecy goodness, an unknown internaut* created the lovely (if a tad vulgar) bit of science communication below. It puts The Flash's amazing cognition--the only way to handle moving at light speed--into perspective: The numeric comparisons are amazing, but this superhuman perception is almost transcendent. When you can process visual information that fast, the world would be crystal clear at any speed. Electrical signals travel and neurons fire in The Flash instantaneously. He could pick out any individual frame from any movie (maybe that single frame of porn from Fight Club). It rectifies the problem of Star Wars-style blurring during light-speed travel that would render any of us blind--like how we would go deaf if we travelled at light speed towards an air horn--and allows the hero to literally think circles around his foes. By contrast, our processing power is far less extraordinary. It is so underpowered that it made life difficult for early television engineers. Neuroscientist David Eagleman explains that engineers were worried about keeping audio and visual signals perfectly synchronized in the first broadcasts until they realized that they had a grace period of around 100 milliseconds. Any two signals played closer together than this the brain would consider simultaneous and sync-up--a correction for slow perception. Two signals played out of step beyond 100 milliseconds made a broadcast look like a badly dubbed kung-fu movie. To The Flash, that's what every TV show must look like. He has the latest episode of The Big Bang Theory rendered unwatchable by our regularly paced brains. With such amazing reflexes, The Flash is the embodiment of the feel-good platitude to "live in the now." Like how Einstein demolished the idea that past, present, and future are absolute, if we had The Flash's cognition it would redefine the human experience. Every TV show, movie, and videogame would look like a series of still frames--the frame rates would have to be astronomical to keep us visually entertained. Your reaction time wouldn't look totally ridiculous. More consequentially, we could discover so much more than our brains can currently detect. There is a superfluity of science enveloped in the ticking seconds that we cannot perceive. Thinking at The Flash's speed would be like living in dreamtime--100 attoseconds is to one second as a second is to 300 million years. You could stop to draw all the intricacies of a fluttering hummingbird wing in complete detail...in between beats. The incredible physics hidden in tried and true chemistry experiments would leap out at us like barking dogs. Light speed perception would be a revolution on par with discovering the rest of the electromagnetic spectrum beyond visible light. Or you could spend your time racing Superman to see who is faster. -- *If anyone knows where the image originated from, let me know and I'll gladly attribute the clever fanboy or girl.
The views expressed are those of the author(s) and are not necessarily those of Scientific American.