Physics is filled with mysteries. To find a few worth exploring, look no further than an ice cube. At room temperature, of course, the cube will melt before your eyes. But even far below freezing, ice can shift in barely perceptible ways that scientists are still trying to understand. Using imaging tools at the U.S. Department of Energy's (DOE) Argonne National Laboratory, researchers have detected a phenomenon known as premelting at temperatures far lower than those previously observed.