# Prelude - The Mystery of the Cosmos ## Direct-Collapse Black Holes - The Quasi Star Almost 300,000,000 million years ago, the first stars formed out of the newborn interstellar medium of the Universe. These stars ionised our stellar medium, burning bright for 10,000 years - mere blips in the Universe's history, they exploded, or rather *imploded* on themselves as a black hole grew within them to swallow them whole. the clump of gas must have a mass of 10^4 - 10^6 solar masses - have been theorised to happen in the earlky universe, not proven - require some special conditions to avoid gas cooling - trigger a GR instability eventually and then the gaseous structure collapses - long bursts theorised to be from CCSNe, core collapse supernovae