When I was eight years old, I had a very specific recurring nightmare.

The Big Bang, the giant fireball that gave birth to our universe.

I'd watch these 90s science documentaries, which would start all the way at the beginning of everything.

The blast generated so much momentum that it's driven the expansion of the universe for 15 billion years.

And eventually they'd make it to the end.

Astronomers have long believed that all the matter in the universe and all the gravity it exerts

should slow the expansion down.

At some point, billions of years from now, the universe would slow down so much that it would stop

expand.

And then, like some cosmic rubber band, it would start to snap back. Slowly, at first, then faster, and faster.

And then at some very distant time in the future, you could imagine a kind of big crunch,

which is the crunching together of the universe.

The big crunch.

I was obsessed with it.

I couldn't stop thinking about everything and everyone I knew just getting smushed together

until we all couldn't breathe.

In the end, in 30 billion years from now, all the matter of the universe would exist as one tiny point,

much as it was at the instant of the Big Bang.

Maybe you don't regularly lose sleep over something that might happen billions of years in

the future. But like, one, I've never really been the best sleeper. And two, come on, it's so

visceral. The crunching. Still messes with me. I used to be up all night, and my dad was pretty

nice about it. He would just keep reminding me about the whole, this isn't going to happen

...