 Extraterrestrial life, especially intelligent life. Well, I've been obsessed with the concept all my life. I've not only written about it extensively from every angle that I can come up with. As a science fiction author, I've written some of the major papers on SETI, the search for extraterrestrial intelligence, and what's called the Fermi Paradox. The question asked by physicist Enrico Fermi, so where are they? Why have we not seen any signs when we've been looking assiduously for 70 years with radio telescopes? And the more we learn about the universe, the more strange this what I've called the great silence seems to be. And everybody has their favorite explanations. It's difficult to make life. Or life is easy, but it's difficult to make intelligence. Or intelligent life kills itself off, which we almost did throughout the Cold War. And there's almost 100 potential explanations for the absence of visible signs that we are in contact with extraterrestrials. And a few of them are really, really nasty. Do I think they are likely? No, I don't think we're about to be invaded by slathering Kardashians, although we have been by Kardashians. I just think that it's prudent for us to talk it all over, explore all the concepts. It's an interesting thought to think about extraterrestrial life and what it is, and where will we find it? It has to exist somewhere. Does it exist in our solar system? Probably. If the right triggers were here on Earth to allow biological growth and those things to occur on Earth, likely we're going to find it somewhere else in the solar system. But I think we'll find it in water-rich areas. Could be one of the moons of the outer planets. Life is very pervasive and will exist in very harsh places. So I think we'll find it if we just look hard enough.