Rare Earth: Why Complex Life is Uncommon in the Universe [Kindle Edition]

If you want a clear, succinct outline of all the forces involved in traversing life's tortured course, you have it here. What is the likelihood another world possesses all the factors needed to drive simple molecules along a track leading to a creature capable of thinking about communicating across vast stellar distances? In dealing with this question, Ward and Brownlee synthesized an immense amount of information, presenting it in a finely crafted style. In fact, the extraterrestrial aspects become relegated to short pieces at chapters' ends. Leaving no stone unturned, the authors deal with cosmology, physics, chemistry and, of course, biology, in easily absorbed prose. Given the wealth of information they needed to survey, no accolade can do sufficient justice to their presentation.

Nearly twenty years ago, James Trefil and Robert Rood published "Are We Alone?". From a list of then-known conditions needed to allow life to begin and evolve, the authors offered optimistic and pessimistic scenarios on whether alien civilizations were likely to exist. Ward and Brownlee have improved the resolution of this question, using the latest information. Sadly, but almost certainly correctly, the come down strongly on the pessimistic side.

Paleontology has come far since Are We Alone? was published. Ward and Brownlee's account surveys utilizes the wealth of recent information derived from research studies done during the past few years. With life beginning over 3 thousand million years ago, their task is formidable. Yet they carry us through the stages life without bogging down in pedantic expression. They show how misleading simple pictures of life's progress can be, showing how even "simple" creatures are astonishingly complex.

The studies and researchers they discuss offer a wealth of new information, including a few acute surprises. Evolution is fraught with disaster scenarios. Ward and Brownlee offer a good discussion of these, particularly the great Permian dying. Diversity loss from this extinction was severe. Was it the result of a reduction in available DNA patterns due to the loss of species? This is a new question for which the authors call for further research in its response.

The most innovative chapter in the book deals with the impact of plate tectonics on evolution. More than simply the drifting of continental land masses, the authors describe how severely mobile continents impact ocean currents, air masses and climate generally. Little considered by paleontologists except as a dating and location device, Ward and Brownlee make continental drift a major factor in evolution. Since no other planet in the solar system exhibits tectonic activity, what is the likelihood this phenomenon occurs on planets circling distant stars? No tectonics, no stimulus to higher life forms and interplanetary communication.

In short, this book covers an immense amount of territory in explaining how life starts and likely continues under the proper conditions. They present nicely balanced explanations and critiques of recent research findings. Even outlandish ideas are given a patient hearing. As they remind us, who would have thought life could dwell at the bottom of the ocean's depths? It's well worth investing in this view of life's history. While posing many questions, the authors show how innovative thinking may someday provide answers . Anyone considering entering a scientific field will discover countless areas of investigation. This book should find a place on your shelves for current knowledge and future reference. Perhaps you might gain a place in a revised edition. [stephen a. haines - Ottawa, Canada]

Ward & Brownlee set out very clearly their hypothesis that complex life is unlikely to be common in the universe. One of the beauties of the book is that it deals with the latest ideas in astrobiology. Using these ideas it sets out the thesis that for simple life to arise in the universe may not be rare, since it took a mere 600 million years for "simple life" to arise after the formation of the earth. However since it then took "complex (animal) life" a further 3 400 million years to evolve it would seem far less likely to occur. Using the earth as their only possible example, the factors needed for complex life to arise - & to be maintained - are explored at length. They conclude that "With the best intentions, but limited by natural laws & materials it is unlikely that Earth could ever truly be replicated. Too many processes in its formation involved sheer luck".

The exploration of these processes in some detail I found both fascinating & easy to read. They ranged from galaxies, the formation of the earth, extremophiles, snowball earth, plate tectonics to the roles of the moon & Jupiter. On another level it provided a fresh way of approaching the evolution of complex life on earth. I became so interested & absorbed in this new material that I read the book for a second time this time making notes for my own use. It has also provided me with jumping off points to find out more on the various topics from the internet.

All in all a real good read. I only withhold one star because I hope, when they produce the next edition, the dog's breakfast that is Fig 9.1 is drastically revised.

"Rare Earth" is a book defending the Rare Earth hypothesis, the idea that life, or at least complex and intelligent life, is very rare in the universe.

Peter Ward and Donald Brownlee believe that simple life forms might be ubiquitous throughout the universe. By simple life, they mean something along the lines of bacteria or archaeans. However, complex life - such as animals - might be comparatively rare. (They don't discuss plants at any length.) The conditions necessary for the evolution of animals might be so unusual, that our own solar system could be the only one where such creatures have emerged. If so, that would make intelligent life even less likely. Perhaps humans really are alone in the universe.

The authors discuss the unusual make-up of our solar system at some length: the sun isn't an average star, the presence of Jupiter tends to shield Earth from approaching comets, our unique moon has an important geological impact on conditions at Earth, plate tectonics are driven by very exotic mechanism, etc. Thus, complex life has evolved due to a long series of highly unlikely circumstances. If the preconditions for animals and thus humans are the results of pure chance, then perhaps it only happened once. Fermi's paradox has been solved: the reason why no aliens have ever visited our planet, is that the aliens don't exist!

For rather obvious reasons, it's very difficult to prove or disprove the Rare Earth hypothesis at present. It remains a minority position within the scientific community. Personally, I also suspect that Ward and Brownlee are wrong, but I admit that my reasons for thinking so are largely philosophical. And no, I won't kill myself is somehow it turns out that the authors are right. I mean, who wants to be fried by the big UFOs in "Independence Day"?

Still, it's interesting to speculate about why the Rare Earth hypothesis is so...well, rare. It's almost an article of faith in our culture that aliens simply *must* exist. Why? I don't think it's because the existence of other civilizations in other star systems would make us more humble and less Earth-centred. Please come on, our civilization is *not* humble, a few symbolic paeans to Copernicus and Freud notwithstanding.

Paradoxically, I think it's a special kind of scientific thinking that fuels the pseudo-scientific alien-mania. If we can find an advanced race travelling the Galaxy in space ships, that would prove that science, high tech and AI actually works. Also, what better argument for funding the space programs than the chase for aliens? Perhaps atheists also need aliens to give the empty materialist universe some semblance of meaning? If you can find meaning in a non-existent sulphur-based life form at Beta Orionis, you have my sympathy. I can't. I like crows and geese, though.

Incidentally, you might want to know that the book Amazon has paired "Rare Earth" with, "The Privileged Planet", is a creationist work. The creationists, of course, claim that all the facts enumerated by Ward and Brownlee can't be a co-incidence. It must be God who is behind it all! (God doesn't like sulphur-based life forms on Rigel. He's more into beetles!)

"Rare Earth" is relatively easy to read, contains many interesting facts and interpretations, and gives you something to think about on a spring evening. I mean, what if we actually *are* alone...in the entire universe? The thought is staggering. I also find the theory expounded in this work hard to swallow, but it should be read with an open mind.