 "Yrast" is the superlative of "yr" and can be translated "whirlingest", although it literally means "dizziest" or "most bewildered".The yrast levels are vital to understanding reactions, such as off-center heavy ion collisions, that result in high-spin states.Yrare is the comparative of "yr" and is used to refer to the second-least energetic state of a given angular momentum.