Intelligent Life in the Universe

"It’s a book with a title which is actually backwards. The first part is about the universe and the environment, the second part is about how life came about, and the third part is about how life becomes intelligent. Carl Sagan’s interest is in what kind of life is out there in other worlds, and whether it could be like us. The reason I chose it is because, although it’s written for a general readership, it doesn’t oversimplify at all. I think that this is probably because it’s based on a book written by somebody in Cold War Russia and so things aren’t oversimplified for a mass media. By the end of the book you realise that you’ve learnt so much about biology and chemistry and physics and how they are all linked together. It will just depend on the environment where we find it. I think that somewhere in the universe there will be something like animals because their environment is similar. There are certain properties of carbon and water, which make them particularly good at making life, and this will probably be a theme for organisms anywhere. Natural selection will also be a unifying theme as well. Apart from these two elements, all bets are off, which is exciting. December 11, 2009. Updated: November 27, 2022 Five Books aims to keep its book recommendations and interviews up to date. If you are the interviewee and would like to update your choice of books (or even just what you say about them) please email us at [email protected] Support Five Books Five Books interviews are expensive to produce. If you've enjoyed this interview, please support us by donating a small amount ."

"This book was written first in Russian by Shklovskii, who was an astrophysicist in what was then the Soviet Union. Carl Sagan had it translated, and he thought it was a great book but he had lots of additional thoughts that he put in. So he annotated the whole thing. They use different fonts for Shklovskii’s writing and for what Carl added to it, and it ended up being a wonderful book that talked about the possibility not just of life but intelligent aliens, with whom we might one day communicate. I run into a lot of pessimists these days, but it is because they have read Rare Earth , which came out about ten years ago. But it hasn’t been addressed by a comparable book in literature, and I am hoping some people will read my book and become more optimistic! For the last 40 years or more, people like Carl Sagan and Jill Tarter, who is now head of the SETI Institute [the search for extraterrestrial intelligence], have been out there looking for intelligent life in the universe. In fact, Frank Drake, who was one of the early radio astronomers in this business and founded SETI, wrote out an equation which is often referred to as the Drake equation. It is a way of estimating the number of intelligent communicating civilisations in the galaxy. They have been looking for extraterrestrial life mostly using radio telescopes. When you do that you are looking for civilisations like ours that broadcast radio signals. That is great, but it turns out we can only eavesdrop for radio signals around a handful of nearby stars, so we really need to extend our search and do it in a different way. From my way of thinking it is getting the cart ahead of the horse. Because before you start looking for intelligent life you should try to figure out if life itself is common. I think that is the most interesting question in the coming decade or two. We need to address the life signal. If you do that we don’t need radio signals. We just need to be able to observe either visible light or infrared radiation from extrasolar planets and look for signatures of atmosphere gases to establish if there is life – and then the next step is to see if it is intelligent."

"This is a great book. It was published in 1966 and I read it in 1968, the year Apollo 8 circumnavigated the moon. It was an exciting time, 2001: A Space Odyssey was released, Star Trek had been on for one year. This is the first astrobiology book. A dozen or more astrobiology books have appeared over the last ten years, it’s become such a hot topic, but many of them repeat this book. Certainly our knowledge of the planets has increased since then. But the underlying principles are still all expounded in this book. It has everything from cosmology, the origin of the universe, all the way up to searching for intelligent life and first contact. You won’t find another book remotely approaching this until ten years ago when the NASA Astrobiology Institute was created. More and more scientists got involved, they started teaching at university level and that’s when the books proliferated. But they still cannot beat this book. After all, it’s Sagan. It was because of this book that it was quick for me to make the connection between subsurface life and life in the universe. Sagan has several chapters about Mars but he never mentions subsurface life because at that time it was not known to exist. He talks about panspermia and he talks about shielding bacteria from cosmic rays during their transport between star systems. But of course he knew nothing about subsurface life, that was the missing piece of the puzzle. So you put those two together and you get to what we’re doing today. The possibility is so close to us. If you look up in the night sky, you see Jupiter. With a pair of binoculars, you can see the Galilean moons flying around it, and the second moon there is Europa, which has an ocean larger than all the oceans on Earth combined. All you have to do is send a probe there—the cost of the probe is really not that much, in terms of the amount of money you spend as a society—to answer that question. It’s right there in front of us; staring at us. You don’t have to send a probe to another star system, it’s right there. The only question really is whether or not, in the history of Europa, life could have originated beneath that icy crust. That’s the real question. We don’t know enough about the origin of our own life to answer it. We know some of the steps, but we’re just not entirely sure whether or not having photons interact with some of these pre-biotic molecules is the key step. He talks a little bit about that in his book as well."