The big question in the search for intelligent life outside our solar system is a simple one: “Where is everybody?” This question arises out of what’s known as the Fermi Paradox, which more or less posits that, given the incredibly large number of stars in our galaxy, not to mention the universe, there should be lots and lots of other planets capable of supporting life, some of that life should have developed advanced technology, and we should have met them, or at least heard from them by now. So, ya know, where is everybody?
It’s almost impossible for most of us to understand astronomical or astrophysical scales, whether they be of time or distance. For example, some quick calculations show that the distance of a light year is what you’d travel if you went from L.A. to Manhattan, turned around and went back, and then made the round trip again about a billion times. But that’s just one light year (5.88 trillion miles) and we’ve now confirmed exoplanets as far away as 13,000 light years and a couple about ten or fifteen light years away, in a total of 3600 confirmed exoplanets so far. Our lonely little galaxy is 100,000 light years across, though, and our closest galactic neighbor, the Andromeda galaxy, is 2.5 million light years away. And there are about two trillion galaxies in our universe, the edge of which is forty-six billion light years away in any direction.
Here’s the point of all this mind-boggling time and distance stuff: if they were ever there, they’re probably gone by now. Some form of life could have developed electromagnetic communication technology, or even near-lightspeed travel, flourished for a million years, died off a million years ago, and we still won’t hear from them for another million years if they were two million light years away, which isn’t even that far, as it turns out.
For me, this yields the conclusion that there is certainly other life, even intelligent life, in the universe, and that we have absolutely no hope of ever communicating with them. It’s entirely possible we’ll hear from them tomorrow, it’s just extremely unlikely they’re still there, wherever they came from. Or maybe they’re just putting the finishing touches on their wormhole device and planning on visiting next summer. Who knows.
This is the kind of thinking and understanding you can expect from Lee Billings’ book Five Billion Years of Solitude. It also chronicles the human stories of many of the pioneers in the field of SETI. Be warned though, the book spends a lot of time examining the fragility of life on Earth itself, making the point that as likely as it is that there’s life outside our solar system, it’s still probably a relatively rare thing, and probably doesn’t last long when it does arise.
Honestly, it’s all a little depressing to me. That’s probably just me, though. Or maybe not. I don’t know. Who knows? Maybe they do. I hope we find out someday. I know that.