Horror stories may be the place for vampires, ghosts and zombies. Just remember, they are not real, warns physicist Costas Efthimiou. Obviously, you might say. But Efthimiou, a professor at the University of Central Florida, points to surveys that show American gullibility for the supernatural. Using science and math, Efthimiou explains why it is that ghosts cannot walk among us while also gliding through walls, like Patrick Swayze in the movie "Ghost." That violates Newton's law of action and reaction. If ghosts walk, their feet apply force to the floor, but if they go through walls they are without substance,...