Physicists describe the two properties of physical laws-that they do not depend on when or where you use them-as symmetries of nature. By this usage physicists mean that nature treats every moment in time and every location in space identically-symmetrically-by ensuring that the same fundamental laws are in operation. Much in the same manner that they affect art and music, such symmetries are deeply satisfying; they highlight an order and coherence in the workings of nature. The elegance of rich, complex, and diverse phenomena emerging from a simple set of universal laws is at least part of what physicists mean when they invoke the term "beautiful."