Exploring exoplanets. They probably think we're out there visiting them. That's totally out of the question. All we can do is try we're stuck here on the Earth. All we can do is use telescopes and cameras and our ingenuity to try to figure out whether planets do exist around nearby stars. So it's kind of amazing that there are 5 or 6 different ways that all work pretty well.

So we're gonna get to your book, Josh, but we're gonna start with the rare earth hypothesis, which is something I've always wanted to ask someone of your incredible intellect and breadth of knowledge, and that's that the conditions that allow complex life on earth are so specific that intelligent life certainly, maybe life at all, is very likely uncommon in the universe. And I wonder how you would react to the statement if you got a letter from God or mother nature and it said life is only existent on earth, everything else is barren, cold, and lifeless. Would you still say there's a point to studying exoplanets?

I think so. I think that the search for life is definitely one of the field's great kind of animating principles, And that's true of the public, and it's also true of scientists. You know, it's it's a a thrill to be able to be part of this very long term quest. And I remain interested in that question. I don't happen to work on it personally. I am not really on a day to day basis trying to find life on other planets. I'm mostly about trying to find the planets and study their properties. And there are a bunch of reasons to do it that have nothing to do with life.

One of them is just generally exploratory. What is out there? We all learned in elementary school about the properties of the planets and solar system, and each one has its own story. You know, Saturn has rings, and Uranus is tipped on its side. So what are the other planetary systems like? What kind of surprising features do they have? Do the planets resemble the ones in our Solar System or or not? And the field has been very good to us in providing lots of surprises and lots of planets that do not resemble any of our friends in the Solar System. So there's an exploratory purpose and then there's a more kind of scientific purpose which is to try and figure out where planets come from. You know, if if we didn't already know planets existed, if we just knew the laws of physics and and we were told okay you're in a C, there's clouds of hydrogen and helium, there's a little bit of heavier elements sprinkled around, What happens next? I'm not sure. It would take a long time before anybody would venture to predict that planets would exist. They're the outcome of a really complicated, really interesting set of processes that we only dimly understand.

So a lot of the the here and now in this field is not about trying to find extraterrestrial life, but it's trying to explore the properties of other planetary systems and figure out where planets come from.

I wanna talk about the only planet we know has life, which is the Earth. And you talk towards the end of the book about Carl Sagan and when he, and other collaborators turned the Galileo spacecraft in on itself. He liked to do that. I mean, he I think he did the Voyager spacecraft bang it came to the pale blue dot, as you know about. And you mentioned in the book the kind of signs of life. There's there's 2 of them in particular that you mentioned, but I wanna highlight a third one when we get to it. Gases in the Earth's atmosphere detectable through spectroscopy Clarke indicative of life, and liquid water, while not, you know, directly, a proof of life is is the indicator of strong potential habitability. Why are we so obsessed with, you know, with with Earth like planets in terms of what could be out there? I mean, surely as, you know, as, they say in in, Star Trek, you know, could be life but not as we know it.

So how is it possible to really make any conclusions from a sample size of 1 that would guide you in your research? How do you handle such such endeavors?