Terms like “heat death”, “big rip” and “vacuum decay” don't sound all that inviting. And they aren't.
They describe a few of the theories scientists have about how our universe will one day die.
But when cosmologist Katie Mack thinks about the end of everything, it gives her peace.
“There's something about acknowledging the impermanence of existence that is just a little bit freeing,” she tells Radio 1 Newsbeat.
I'd be willing to bet there aren't many people who feel that way – but even for Katie, it's not quite as simple as it sounds.
Sharing the terror
Katie can still remember vividly when she first realised the universe could end at any moment.
“I was sitting on Professor Phinney's living room floor with the rest of my undergraduate astronomy class for our weekly dessert night, while the professor sat with his three-year-old daughter on his lap,” she writes in her new book, The End of Everything.
She learned that scientists have no idea why the early universe expanded in the way it did – what's called cosmic inflation – and that means they also have no way of saying space won't start violently, rapidly ripping apart again at any moment.