I have to admit, I would have never thought when I started this podcast that we'd end up here at episode 250.

I mean, I suppose I understood that fact in an abstract sense that, yes, if I kept the show going,

that eventually the numbers would tick up

and I would reach 250. But I suppose also that I never thought of it in concrete terms,

that someday, years after I started, we'd still be exploring complete knowledge of time and space.

And I'm perfectly aware that this is technically

episode 251, and I meant to do this last episode, but I got carried away with the constants

of nature stuff, so here we are. And on these landmark episodes, I like to be a little self-indulgent.

Not entirely self-indulgent, because I have several perfectly real and valid questions

regarding today's topic, but it's a little self-indulgent because that topic is indeed

a subject near and dear to my heart, the vast emptiness that dominates our universe.

You know it, everybody's favorite, the cosmic voids.

Believe it or not, I've been working off and on with

voids since the inception of this podcast. Our first episode launched in January of 2015, and at that

time I had just finished a research stint at the Paris Institute of Astrophysics, where I was

working almost exclusively on Voids.

As the years have gone on, I've put down Void research, picked up other kinds of research,

dove headfirst into science communication, done all sorts of wild things I would never

thought possible, like writing books and getting exotic cheese recommendations, but I never

quite let go of Voids, even if my primary interests, research

and otherwise pulled me in different directions. But even though the universe may be flat,

our experience of it can be curved. So here I am in my own future, roughly back where I started,

...