Two Kinds of Science-Fiction Innovations

Most common are the fictions that begin with Jules Verne, and concern the single artifact—a submarine, flying machine, or death ray—and its consquence for all of humanity. These extraordinary voyages—to use Verne's term—play along the fault line between what we think we are and what we can do. Nemo is no accident, or a tragic figure, but the natural consequence of the intersection between present-day humanity and extraordinary technology. Even 2001: A Space Odyssey plays on the same t...

 The One-Electron Universe

I received a telephone call one day at the graduate college at Princeton from Professor Wheeler, in which he said, "Feynman, I know why all electrons have the same charge and the same mass" "Why?" "Because, they are all the same electron!" And, then he explained on the telephone, "suppose that the world lines which we were ordinarily considering before in time and space - instead of only going up in time were a tremendous knot, and then, when we cut through the knot, by the pl...

 The Comet Loss Cone

To understand why comet showers occur, we go back to the Oort Cloud. The theory of comet showers was worked out by Jack Hills, an American physicist now at Los Alamos. He realized that the movements of the comets in the Oort Cloud are not entirely random. Comets in the cloud are generally moving in random directions, but if a comet happens to be moving in an orbit almost exactly toward the Sun, it will not survive for long. A comet in an orbit coming close to the Sun may get boiled away and d...

 Science Manipulates Language to Make it More Precise

Let us consider two spheres moving in different di- rections on a smooth table. So as to have a definite picture, we may assume the two directions perpendicu- lar to each other. Since there are no external forces acting, the motions are perfectly uniform. Suppose, further, that the speeds are equal, that is, both cover the same distance in the same interval of time. But is it correct to say that the two spheres have the same velocity? The answer can be yes or no ! If the speedo- mete...