But something that’s not appreciated by the public is, in fact, that the experiment continues to get better, and, consequently, tends to get faster. This is a little plot, and every time you show a plot, you lose 10% of the audience. I have 12 of these. But what I plotted here is just some metric that shows how fast we’re searching. In other words, we’re looking for a needle in a haystack. We know how big the haystack is. It’s the galaxy. But we’re going through the haystack no longer with a teaspoon but with a skip loader, because of this increase in speed. In fact, those of you who are still conscious and mathematically competent, will note that this is a semi-log plot. In other words, the rate of increase is exponential. It’s exponentially improving.
Now, exponential is an overworked word. You hear it on the media all the time. They don’t really know what exponential means, but this is exponential. In fact, it’s doubling every 18 months, and, of course, every card-carrying member of the digerati knows that that’s Moore’s Law.
So this means that over the course of the next two dozen years, we’ll be able to look at a million star systems, a million star systems, looking for signals that would prove somebody’s out there. Well, a million star systems, is that interesting? I mean, how many of those star systems have planets? And the facts are, we didn’t know the answer to that even as recently as 15 years ago, and in fact, we really didn’t know it even as recently as six months ago. But now we do.
Recent results suggest that virtually every star has planets, and more than one. They’re like, kittens. You get a litter. You don’t get one kitten. You get a bunch. So in fact, this is a pretty accurate estimate of the number of planets in our galaxy, just in our galaxy, by the way, and I remind the non-astronomy majors among you that our galaxy is only one of 100 billion that we can see with our telescopes. That’s a lot of real estate, but of course, most of these planets are going to be kind of worthless, like, Mercury, or Neptune. Neptune’s probably not very big in your life.
So the question is, what fraction of these planets are actually suitable for life? We don’t know the answer to that either, but we will learn that answer this year, thanks to NASA’s Kepler Space Telescope, and in fact, the smart money, which is to say the people who work on this project, the smart money is suggesting that the fraction of planets that might be suitable for life is maybe one in a thousand, one in a hundred, something like that. Well, even taking the pessimistic estimate, that it’s one in a thousand, that means that there are at least a billion cousins of the Earth just in our own galaxy.
Okay, now I’ve given you a lot of numbers here, but they’re mostly big numbers, okay, so, you know, keep that in mind. There’s plenty of real estate, plenty of real estate in the universe, and if we’re the only bit of real estate in which there’s some interesting occupants, that makes you a miracle, and I know you like to think you’re a miracle, but if you do science, you learn rather quickly that every time you think you’re a miracle, you’re wrong, so probably not the case.
All right, so the bottom line is this: Because of the increase in speed, and because of the vast amount of habitable real estate in the cosmos, I figure we’re going to pick up a signal within two dozen years. And I feel strongly enough about that to make a bet with you: Either we’re going to find E.T. in the next two dozen years, or I’ll buy you a cup of coffee. So that’s not so bad. I mean, even with two dozen years, you open up your browser and there’s news of a signal, or you get a cup of coffee.
Now, let me tell you about some aspect of this that people don’t think about, and that is, what happens? Suppose that what I say is true. I mean, who knows, but suppose it happens. Suppose some time in the next two dozen years we pick up a faint line that tells us we have some cosmic company. What is the effect? What’s the consequence?
Now, I might be at ground zero for this. I happen to know what the consequence for me would be, because we’ve had false alarms. This is 1997, and this is a photo I made at about 3 o’clock in the morning in Mountain View here, when we were watching the computer monitors because we had picked up a signal that we thought, “This is the real deal.” All right? And I kept waiting for the Men in Black to show up. Right? I kept waiting for — I kept waiting for my mom to call, somebody to call, the government to call. Nobody called. Nobody called. I was so nervous that I couldn’t sit down. I just wandered around taking photos like this one, just for something to do.