Rare Earth: Why Complex Life Is Uncommon in the Universe

I discovered this title in a review in the Boston Sunday Globe a few years ago and decided to try reading the book. To my great pleasure, I found that the authors had done their job well. Although they are pretty sure, given the present state of our knowledge, that advanced life is almost improbable elsewhere in the universe, they continually provide views apposing theirs....so the book is not merely a vehicle to broadcast their own bias [note especially their summation: pp 282-287] They also assert quite strongly that since these studies are just beginning, future discoveries could completely alter the picture as they see it. In addition, the writing, especially considering the material they are discussing, is surprisingly easy to read and understand and totally lacking the 'jargon' so prevalent in today's academic world. I highly recommend this book to anyone who really wants to consider the implications of their thesis.

This is one of the most astonishing books I have ever read. Its thesis, that complex life similar to life on the Earth, is probably very rare in the galaxy, if not the universe. The authors meticulously build a case for Earth's special place in the cosmos, showing how bacterial life might be common but that anything bigger than simple organisms might not be able to survive the ravages of time and comets and wandering axial tilt. As other readers have pointed out, this doesn't necessarily mean that silicon-based life or some other kind of life can't exist in the universe, but it does demonstrate that Fermi's Dilemma might in fact be true. As a science fiction writer, I was stunned at how much this book could change the way science fiction is written. No more Star Trek universes with complex life in every system, no more "federations" or "foundations" or "assemblies" of thousands of inhabited worlds. According to the thesis Ward and Brownlee present, habitable worlds might be few and far between. Humans may very well find no other worlds beyond the Earth upon which to live. RARE EARTH will make it difficult to read books or watch movies that envision a galaxy filled with wonderful and curious creatures, where humans spread out across the galaxy as if they were so many islands in Polynesia. And if the Rare Earth hypothesis is true, then we are also obliged to get our act together here and now if we are going to become a space-going species. I think this book puts a lot of science fiction writers out of business. It certainly makes a lot of science fiction, including my own, seem downright silly.

Rare Earth is a fascinating book that argues that intelligent life is rare in the universe. The value of this book does not lie in the cogency of its arguments but rather in the panoply of interesting facts and theories the authors marshal to argue their point. The authors contend that simple unicellular organisms are ubiquitous in the universe, if not potentially in our solar system. They base their argument on the Draconian environments here on earth where extremeophiles survive. They contend, however,that only a set of unique circumstances could allow unicellular organisms to develop into complex metazoans. The unique conditions include the position of a planet in a solar system, the position of a solar system in a galaxy, and the close proximity of both a large planet and a large moon. Furthermore a planet requires earth-like plate tectonics and maybe a couple of ice ages thrown in that dwarf our previously known ice ages in severity and longevity.(They describe the new theory of "snowball earth"). The weakness of their argument lies in their emphasis on the conditions necessary for life rather than the process. The formation of a complex molecule, RNA, necessary for life, and DNA, necessary for reproduction, might be a far more difficult process than the evolution of microbes to complex organisms. They also make their argument from a strictly anthropic point of view,ignoring the possibility of completely different forms of life. It seems axiomatic that the more complex the life form becomes in any habitat,the more specialized the habitat must become to sustain that life. In any case, intelligent life can be extraordinarily rare but be far from unique due to the vastness of our universe. New theories of inflation, especially chaotic inflation, suggest that the visible universe with its one hundred billion galxies is merely a speck in the much larger cosmos. In summary, even though I don't always agree with the authors, this book is too interesting and informative not to read.

These two authors have written a highly informative book to support their thesis that we might well be the only multi-celled organisms in the universe. It should be stressed that Ward and Brownlee feel strongly that there are probably simple, bacteria like creatures on other planets, but nothing more complex. This is a most interesting book even if you do not agree with their hypotheses. It provides an entertaining and accessible summary of the biological, cosmological, and geological science involved in the development of our home planet. W & B feel that the necessary conditions for complex life are so numerous that few, if any, planets elsewhere could meet the requirements.Read this book and see: 1. Why the moon and Jupiter are essential for our existence. 2. Why a system of plate tectonics is vital for the development of life forms. 3. The effects that mass extinctions have had on evolution. 4. Why life may have originated in the deep ocean near hydrothermal vents. 5. Why earth is very lucky to be located on the far edge of our galaxy.For the scientific oriented layman this book is a true gem.

This is the best book that I have seen on the subject of extraterrestrial life and the possibility of its occurrence beyond our solar system in a long time. In order to make the most accurate prediction possible the book makes use of the strongest evidence we have to date, our knowledge of our own solar system. Using very wide breadth, the authors rationalize the following simple theme, "The occurrence of simple microbial life is pervasive in the universe, but the occurrence of more complex, multi-cellular life is not. From this book I now realize that the number of natural phenomena affecting the possible occurrence and evolution of complex life in one of our neighboring stars is far greater than I ever imagined. I thank the authors for enlightening me on this subject. Perhaps in future I won't be as disappointed as I was during the first Viking landing. I really did think they would find vegetation on Mars, and I'm still upset about it.The authors of "Rare Earth" present their subject very well, although perhaps not in a style that would excite the average public, as did Carl Sagan and Issac Isamov in their science books. Indeed, I recommend that the authors of this text consider rewriting it in a more popular form, with plenty of illustrations. Hey, people love pictures, myself included.The controversy between the people at SETI and the authors is unfortunate. I believe both sides have a lot to gain from each other's work. In my opinion it was a mistake for the authors to have included, near the very end of the book, references to SETI. The antagonism created was predictable. I myself am a participant in the seteathome project, having completed 225 work units so far. However, I do not allow my excitement over the possibility of receiving an alien signal stand in the way of my objectivity in the face of the best hard evidence we have to date. Besides, I take it not as fact, but simply as the best prediction I have heard anyone say so far. It is the closest to fact that we can get at this time. Hopefully soon we will get closer.