At the very dawn of time, the Big Bang blew the universe into existence. The debris of the detonation created and is still creating planets, stars and comets. Eternity’s clock started ticking. Stephen Hawking said so. It must be true.
The scientific consensus is that the universe was probably born in The Big Bang the beginning of time and space. It's far less certain how the universe will end. Theoretical astrophysicist Katie Mack outlines the possible fates of the universe in her book, The End of Everything (Astrophysically Speaking).