No, you don't have radioactive hands -- what's happening, the researchers say, is that a big part of what we see every day comes not from our eyes, but from what our brain expects to see based on other sensory information. Ah, so you're just imagining those hand movements, right? Not really: For the experiment, participants were put in a completely dark room with sensors that kept track of their eye movements. It turns out that when you move your hands in the dark, your eyes move exactly the same way they would if you could actually see them. Your sense of sight may be slacking off right now, but you're still getting signals from other parts of your body, which "create real visual perceptions in the brain." In simpler terms, you're fucking Daredevil.
But you keep stumbling into furniture at night because you're also fucking clumsy.
And if whoever threw you in a dark room also tied your hands, you can always use your nose to navigate. In an unrelated experiment, blindfolded people were able to find their way back to a specific place in a room by using only smelly sponges as reference. This is called using our "smellscapes" (we tragically wasted the term "smell-o-vision" long ago), which are maps we create in our heads by noticing the differences in how each place smells. Rats and pigeons do this all the time -- we just haven't had the chance to exercise this particular ability, is all. Should you ever find yourself in a blackout with two friends who had Mexican food, though, then definitely give this a shot.