Light offers high-resolution information across great distances (you can’t hear or smell the moons of Jupiter or the Crab Nebula). So much information is carried by visible light that almost everything from a fly to an octopus has a way to capture it---an eye, eyes, or something similar. Our eye each have about 125 million rods and cones---specialized cells so sensitive that some can detect a mere handful of photons. “About one-fifth of your brain does nothing but try to deal with the visual world around you,” says physicist Sindney Perkowitz, author of Empire of Light