cosmic microwave background radiationˈkɔzmikˈmaɪkrəˌweɪvˈbækɡraundˌreidiˈeiʃən 基本英英 第二讲宇宙微波背景辐射 Noun: cosmology the cooled remnant of the hot big bang that fills the entire universe and can be observed today with an average temperature of about 2.725 kelvin