This book is a kind of snapshot of where we are, technologically and culturally, in our quest to find out whether there is life elsewhere in the universe. While I was reading it, I couldn’t help but wonder where you think this question stacks up against the other big, primary intellectual inquiries. Is this ultimate question right now? If not, what is?

The book’s central question isn’t really whether or not life exists elsewhere in the universe. If that was the central question, I would’ve included much more detail about research into the origins of life, and about the prospects for extraterrestrial life within our own solar system. I’m inclined to believe that life is an emergent cosmic phenomenon, something as inevitable in our universe as the formation of stars and galaxies, and that perspective certainly informs the book. So piling on pages and pages of detail and debate about how life might emerge on a planet seemed to me a case of missing the forest for the trees. The book is less about life’s origins and more about what life does after it gets started on a planet like Earth.

Because, if you think about it, if life is so common throughout the universe, you have to wonder why everything we see out there looks so dead. I’d guess it’s because most life is actually quite hard to detect over cosmic distances, because it doesn’t end up progressing to sentience and technology. It doesn’t end up building starships and interstellar beacons to explore and communicate with the rest of the galaxy, at least not in any obvious way we can easily see. Put another way, right now it looks like most life out there doesn’t do the things that we like to tell ourselves we’ll eventually do. Short of joining in the search myself or just writing extremely speculative science fiction, it seems the only way to get at why that might be is to take a long, hard look at our current situation on Earth in light of recent discoveries about other planetary systems and our own world’s deep past.

So the book’s real central question is what the future holds for life—particularly intelligent life—on this small world orbiting a lonely star. We already know that someday our Sun will cease to shine, bringing life on Earth and in the solar system to an end. Can we—will we—avoid this dismal fate forecast for us by stellar astrophysics? No one really knows that answer yet. And perhaps that’s not an “ultimate” question in the big universal scheme of things. But perhaps it is. I certainly think that, either way, it’s of immense importance to everyone in the here and now on Earth. The book’s core theme, if it can be said to have one, is that the question of life’s future on (or off) this planet is not only worth asking, but also more urgent than commonly believed.

One of the really striking things about this book is its unflinching tone. I’ve interviewed a fair number of astronomers, and I know how easy it can be to slip into a romantic mode about it. The people and the settings and the technology all lend themselves to triumphant narratives, but you have stayed remarkably disciplined here. Rather than retreating into overly optimistic futurism, the book really captures just how heartbreaking it can be to talk to high-level astronomers right now. It made me wonder what it’s been like for you to spend so much time with these driven, idealistic people who are being forced to kind of sit around and stew in deep curiosity while the values of the culture at large catch up with them?