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 — with another bang or a dark, frozen whimper or something far weirder. Katie Mack is a theoretical astrophysicist at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario, and a rising star in cosmology who studies the possible fates of the universe. She's the author of The End of Everything (Astrophysically Speaking). The good news is that the universe probably won't end until billions of years from now. The bad news is the "probably."