 For this segment, we'll be reviewing Steven Webb's If the Universe is Teaming with Aliens, Where is Everybody? Now, this book is a favourite of notice space explorer Elon Musk, who we've discussed many times on this programme, and the book deals with the Fermi Paradox, which was postulated by famous physicists Enrico Fermi. Now, the paradox says that the universe is really old, within the universe are a lot of galaxies, within the galaxies are a lot of planets, and some of these planets should have the ability to host intelligent life forms. And yet, we haven't heard from any of them. And so, the book kind of discusses reasons why these extraterrestrial civilisations, or ETCs as they're known in this, haven't been able to communicate with us. Yeah, the book lays out about 75 different solutions to the Fermi Paradox, and we'll spare you going through all of these. However, they fall into three main categories. The first is that the aliens are already here, either we're the aliens, the aliens are observing us, and we don't know. The second is that the aliens exist, but they can't communicate with us. Either they're not advanced enough, or they're simply too far away. And then finally, is the idea that we're alone in the universe. There's no other intelligent species out there. Now, I know both of us have thoughts on this going into the book. Adam, did the book change your opinion in any way? It certainly made me aware of just how miraculous it is that we have life on Earth. Because there's so much that has to go right, and there's also so much that you have to avoid going wrong. I'm just going to call out a few examples. Webb mentions things like the moon being absolutely essential, because it does things like regulate tides, and it also gives us a slight axial tilt on Earth, which gives us the nice seasons we're accustomed to, as opposed to being alternately burnt and frozen by the sun. He also mentions things like plate tectonics being important. By splitting apart pieces of land, you basically get species that develop in different climates, and that contributes to the sort of genetic diversity you need to survive the near extinction level of events that pop along every once in a while. In terms of things you have to avoid, there's obvious stuff like meteorites, the kind of stuff that would make dinosaurs extinct. As advanced as we are, we don't really have the capabilities right now to deflect a significant meteorite. If one hit, we'd be pretty screwed. The other thing Webb mentions are gamma ray bursts, which are these massive explosions of energy. And again, if your planet is unfortunate enough to get in the way of one of those, there's really not much you can do as a civilization to survive one. Yeah, absolutely. Going through this, though, I thought that perhaps Stephen was a little bit too anthropocentric, and that he thinks of humanity as being this unique thing that all of the conditions in the universe have to be meant to create. Now, obviously, we have the ultimate selection bias. We only know of one advanced civilization that exists, our own. And so we really can't decide what other civilizations might look like. That said, he really comes to the conclusion that human life elsewhere in the universe is unlikely. And the reason why is because we rely on water or carbon-based life forms, and all these things are relatively recent in the universe's history, and it would be unlikely to have been generated earlier than we find them now. So I would actually want to take an anthropocentric view of things, as you say, and point out that humans have barely been around at all. We think the universe is about 14.8, 15 billion years old, but humans of the species have only been around about 175,000 years. And in addition, we've only really had the technology to detect, say, a radio signal for less than 100 years. And so in that sense, we barely started listening to ETCs. Yeah, there was a really interesting example in the book which I loved, which talked about, let's say we take a radio engineer from the 1920s and we put them in New York City today, and we asked them to detect the signals that are flying around. Well, it turns out in 1920, you didn't know about FM communication, you certainly didn't know about XM communication. So all of the things that people in New York might be listening to, this engineer could never find. It would all sound like noise, and perhaps that's exactly what we're running into today. So if you think about the radio spectrum that's out there, it runs from about one metahertz to 300 gigahertz. That's a huge spectrum, and we just don't know where to look, and so it's totally possible that aliens are sending the signals all the time, but we're not looking at them. So not only do we have this broad radio spectrum to try and hunt for this elusive ETC signal, but I also wonder how long we have left to keep looking. There's some interesting stuff in the book about how long the human species as a whole has left, and you can do these interesting back-of-envelope calculations. One method was proposed by Richard Gott, where he basically said that if you treat each observation in time as a random one or from a uniform distribution, you can say that with 95% probability, you've got about one-thirty-ninth to thirty-nine times whatever your observation is left. So he used this originally to calculate how long it would be before the Berlin Wall came down, but you can do the same thing for human species, whereby if you take the 175,000-year number I mentioned, you come up with a figure that we had between 4500 years and about 7 million years left. Now, it sounds like a lot, but it's really not in terms of the grand scheme of the universe, and so I think you can think of intelligence as being kind of these breached sparks in the night, whereby intelligence civilizations develop, but then they burn out so quickly, but we never actually have time to intercept another ETC that's at the same level that we are, and that's why we haven't had any communication. Yeah, I think one interesting question to ask about this book is why does Elon Musk like it so much? And one of the things that's clear to me is that it's very possible we're the only advanced civilization, at least in our area, and we could be perhaps even the first advanced intelligence to conquer the universe, and I think this appeals greatly to Elon Musk. He would love to be the person who sort of sparks this colonization effort and really brings humanity as the master of the universe. Why don't I think Elon has to worry about running into any ETCs as part of his space exploration? Because this book has really convinced me that when you consider the difficulty of starting life, the difficulty of reaching the level of intelligence required for interstellar travel communication, and the fact that the ETCs, after all this, would actually have to want to communicate with us, and it's very unlikely that we've run into an extraterrestrial civilization in our lifetimes. And having said that, I think that's a really, really good thing. I don't want to meet an ETC. I think you'll be potentially disastrous for the planet, and I'm quite happy being an only child, being alone in the universe. Adam, I agree with you on the danger, but I am more than excited to meet an ETC. And I'll tell you why. In the book Super Intelligence, we laid out the argument that even though a super intelligent AI is going to be incredibly dangerous, it could wipe out humanity. People are going to be incentivized to create such a thing because they want to see the benefit in their lifetime. Now, it might kill them, but they're hoping that it won't, and they want to see the positive side. You can think about alien civilizations as being the same way. Yes, the aliens most likely will show up and immediately kill us because we provide no value to them. However, it's also possible they'll share their advanced technology and bring in a golden age of humanity. And so for that reason, I am more than excited to have them show up and greet us with fond regards. Well, if there are any aliens watching or listening, I'd encourage you to check out the rest of our Random Talkers back catalog and consider subscribing on YouTube. This has been Random Talkers. Thank you for tuning in.