Research in Argonne’s Physics Division seeks to understand the origin, evolution and structure of the ordinary matter in the universe – everything made up of protons, neutrons and electrons. Through the operation of the Argonne Tandem Linac Accelerator System (ATLAS) as a national user facility, as well as diverse research programs in low energy, medium energy, accelerator and theoretical nuclear physics, Argonne’s Physics Division investigates how stars form and how different elemental isotopes – especially exotic short-lived ones – are created and structured.