Historically, supernovae have fallen into two main types: thermonuclear and iron-core collapse. A thermonuclear supernova is the explosion of a white dwarf star after it gains matter in a binary star system. An iron core-collapse supernova occurs when a massive star runs out of nuclear fuel and its iron core collapses, creating a black hole or neutron star. A worldwide team led by University of California - Santa Barbara (UCSB) researchers at Las Cumbres Observatory has discovered the first convincing evidence for a new type of stellar explosion — an Electron-Capture Supernova, or a “Goldilocks Supernova,” which falls between the two major types. While this new type of supernova has been theorized for 40 years, real-world examples have been elusive until now. The discovery also sheds new light on the thousand-year mystery of the supernova from A.D. 1054 that was visible all over the world in the daytime. This supernova in 1054 eventually became what we observe today as the Crab Nebula (NGC 1952 or M1).