What determines whether complex life will arise on a planet, or even any life at all? Questions such as these are investigated in this groundbreaking book. In doing so, the authors synthesize information from astronomy, biology, and paleontology, and apply it to what we know about the rise of life on Earth and to what could possibly happen elsewhere in the universe. Everyone who has been thrilled by the recent discoveries of extrasolar planets and the indications of life on Mars and the Jovian moon Europa will be fascinated by Rare Earth, and its implications for those who look to the heavens for companionship.
Unfortunately, the whole issue is so largely speculative. The authors contradict themselves at times with their conclusions. They frequently make comments like, "since this is the way it happened on Earth we don't see how it could happen elsewhere differently." Conclusions based on a case study of one make accurate predicting possible.
I heard of this book during Odyssey 2005 from guest lecturer Allen Steele. He gave a lecture on world-building, and passed out some of the references he had used while creating the solar system and planet for his Coyote series (I say series because at this lecture, he made a few comments that made me suspect a fourth volume is in the works). Rare Earth was one of his titles.
The reason I picked it up, aside from general curiosity about the various theories populating the chances of life outside our planet, was also for research material. Not that I had a particular project in mind at the time, but I thought that it would be a good idea to have this book under my belt for future stories (and one current one) that took place on extrasolar planets.
Rare Earth has a lot of interesting info. It goes into all kinds of reasons why animal life (the authors are quick to note that they do believe microbial life, like bacteria, is likely very common) is rare in the universe. The writers discuss the Cambrian Explosion, Snowball Earth, plate tectonics, impacts and extinctions, Jupiter, the moon, and the habitable zone of our solar system. All of which is divided into manageable chunks that lead from one section to the other. The writers also continuously repeat their points, just in case you missed them the first time.
Given the nature of the book (it’s more general science than theory), it’s hard to actually recommend. The hardcover edition was published in 2000, and the trade, which I read, in 2004. There’s a preface to the trade edition where the authors say that despite then-current observations and discoveries, they pretty much stand by their theories as presented in the book—indeed, the only corrections made were typos and such. But science has a way of jumping forward, and from recent articles in magazines like “New Scientist”, some of their then-current information is now wrong. The biggest two I noticed were the fact that there have been several terrestrial planets discovered, three of which posted in a 5/17/06 article on New Scientist’s website, all of them in the same system (and Neptune-sized!). There’s also a recent discovery that humanity did not originally migrate to North America from the Bering Strait—older remains, though currently disputed, have been found in South America.
Of course, all of this is very recent science. :) But given the fact that I’ve only recently begun to watch current scientific trends, I was constantly aware of what else could be considered wrong now that wasn’t when this book was published. Granted, it’s only been two years, but still, that’s a long time.
But I can’t fault the book in terms of interesting information, especially since it spawned a few vague story ideas and also gave me some interesting, supportive evidence for my own alien race in my novel. I am also glad to have read this now, before I tackle Darwin’s The Origin of Species.
Don’t get me wrong, though: for anyone convinced of intelligent life out there in the universe, this book is a total killjoy. The writers admit, at the very end, that they may lack imagination, that all of their evidence is based on what we know from our own planet, and that other worlds and other life may be creatively different. But they don’t think so. Personally, I think they rejoice in the idea that Earth and her people are not mediocre, that we aren’t one of many, that on a whole, we are a beautiful, unique, snowflake in the universe.
But at least they admit that astrobiology is clearly in its infancy, and that scientifically, we have a long way to go in terms of discovering the wonders of the universe. Who knows what such future science will reveal? Only time will tell.
Until then, it’s not a bad book to read, regardless of your beliefs. Especially if you write SF that involves other planets: this book at least gives solid facts as to what a planet would be like if tidally locked to the sun, or if the moon’s orbit around the earth were the exact opposite. So there’s fun facts, but in terms of research material, don’t let this be your only source.