Universally slow

Glassy systems are very common in nature, from disordered electronic and magnetic systems to window glasses and crumpled paper. Among their key properties are slow relaxations to equilibrium without a typical timescale, and dependence of relaxation on the system's age. After reviewing some of these physical systems, I will describe our approach to the problem, and show how it leads to a novel class of aging. The slow relaxations result from a broad distribution of ``relaxation eigenmodes,'' which relates to a particular class of random matrices. I will discuss recent results on the structure and localization properties of these modes, and their implications.