[.ca] Rare Earth: Why Complex Life Is Uncommon in the Universe (ISBN 0387987010)

From Amazon.com:
"Do you feel lucky? Well do ya?" asked Dirty Harry. Paleontologist Peter Ward and astronomer Donald Brownlee think all of us should feel lucky. Their rare Earth hypothesis predicts that while simple, microbial life will be very widespread in the universe, complex animal or plant life will be extremely rare. Ward and Brownlee admit that "It is very difficult to do statistics with an N of 1. But in our defense, we have staked out a position rarely articulated but increasingly accepted by many astrobiologists." Their new science is the field of biology ratcheted up to encompass not just life on Earth but also life beyond Earth. It forces us to reconsider the life of our planet as but a single example of how life might work, rather than as the only example. The revolution in astrobiology during the 1990s was twofold. First, scientists grew to appreciate how incredibly robust microbial life can be, found in the superheated water of deep-sea vents, pools of acid, or even within the crust of the Earth itself. The chance of finding such simple life on other bodies in our solar system has never seemed more realistic. But second, scientists have begun to appreciate how many unusual factors have cooperated to make Earth a congenial home for animal life: Jupiter's stable orbit, the presence of the Moon, plate tectonics, just the right amount of water, the right position in the right sort of galaxy. Ward and Brownlee make a convincing if depressing case for their hypothesis, undermining the principle of mediocrity (or, "Earth isn't all that special") that has ruled astronomy since Copernicus. --Mary Ellen Curtin

For THINKERS Only!!!:
This book has a number of good features -- (1) References: over twenty-five pages that mainly consist of recent journal articles written by respected scientists. (2) Two 2-page introductions that summarize the entire book. These are entitled "Dead Zones of the Universe" (where Life As We Know It, LAWKI, is postulated not to exist) and "Rare Earth Factors" (18 factors that may be unique to Earth and that permit LAWKI). These provide a kind of roadmap for the first ten chapters of the book. (3) The first ten chapters are very detailed and build-up (using both historical theories and data as well as recent new theories and data) the summary information mentioned in (2) above. (4) The last three chapters are particularly interesting. Here we get more aquainted with the authors' Rare Earh Hypothesis (microbial life is common in the universe, but multicellular animal life is rare) and introduced to the Rare Earth Equation (which challenges the assumptions of the famous Drake equation). (5) The honesty of the book. The authors state, "Perhaps Earth is not rare after all but is simply one variant in a nearly infinite assemblage of planets with life." In other words, they acknowledge that life as we DON'T know it may possibly exist. In conclusion, for those thinkers who want to read a book on the cutting edge of modern scientific investigation, this book is for you!

Gloomy picture for us Trekkies!!:
I both hate & love this book. I think it is a must read. Like all reviewers here, I am one of those who hopes that it's a "Star Trek" universe out there but unlike other reviewers on this board, I do not think that this book will get outdated anytime soon. This book without trying, seems to partially reconcile the 'Creation' & 'Evolution' hypothesis. It does this by sticking to the 'Evolution' script but listing powerful arguments as to why 'Life' as we know it may be unique or at least rare. In the face of mounting evidence, perhaps the church could support this hypothesis without losing legitimacy. The hypothesis is not built on one single argument & therein lies its strength. The book starts by making a clear distinction between microbial & animal life and concedes quickly that the former may be quite common around the universe. Animal life on the other hand, requires a fortuitous alignment of the stars and planets :) The first concept explored in this regard is that of a 'Habitable Zone'(HZ). Off the 3 types of galaxies, only large spiral galaxies are likely to host life. The other two types are either too dense (globular galaxies) or too old (elliptical galaxies & small clusters), lacking the heavy elements necessary to sustain habitable conditions. The former is a problem of overcrowding, too much sun (literally), gravity, harmful radiation & frequent cataclysmic events (supernovae, black holes etc.). The latter would mean a world without a heated core, mostly composed of hydrogen & helium. Think of the Sun & Jupiter, what are the odds of life in these two places. After eliminating all but spiral galaxies, the hypothesis also does the same to systems within spiral galaxies. Too close to the core and you have the same problems faced within globular galaxies, too far & you have the environment similar to an elliptical galaxy, i.e., too few heavy metals. That leaves only the arms of spiral galaxies as likely habitats for complex life. Within the HZ of galaxies, planets also have to be formed within the HZ of their star. Too close & they're toast (all water evaporates and escapes into space), too far and they are too cold to sustain anything but microbial life. Additionally it requires a star with certain properties, a certain size (only 5% of stars are the required size, most stars in the universe unlike our Sun are too small) and a high percentage of heavy metals (again a rare combination). Finally, the roles played by the Moon & Jupiter in supporting life on earth. The Moon stabilizes the rotation of the Earth. Imagine a basketball rolling on a floor rotating in varying directions as opposed to a top, rotating on a fixed axis. Without the Moon, the poles & equator would be constantly shifting. Our planet would be covered by water, temperatures & seasons would be unpredictable. Without Jupiter (because of its size & gravitational pull) attracting and capturing most celestial objects on a collision course with Earth, there would be many more large bodies crashing on earth and threatening life. You know what happened the last time this happened, ask Mr. T-Rex. Even assuming all these factors are duplicated, there is the additional factor of a time period. This ranges from the time the solar system has cooled down & the planets settled into stable orbits to the end when the star runs out of fuel & dies. Complex life has this time span to evolve, live & likely perish. The Rare Earth hypothesis is exactly that, it is not a law. Ward & Brownlee make a strong case, one whose implications I don't like but are nevertheless persuasive. If you are students of science, the origin and future of mankind, I would strongly recommend you read this book.

Not Up to Snuff:
OK, I am in the obvious minority with this review, but it's how I see it. This is a work filled with broad, sweeping suppositions, yet it seems that as always the devil is in the details and I was left unconvinced that the authors really had the details right to support their "Rare Earth" theory. It is an interesting, if ultimately unconvincing book. Interesting theory, lots of conjecture, and lots of "What if..." in every chapter. To me it seems that in many places sweeping statements are made, but never supported. Take for instance the statement on page 110 "Changes in ocean chemistry caused by increased tectonic activity beginning a billion years ago facilitated the evolution of skeletons." But the section does not, to me, provide adequate support or explanation for this supposition. Also take for example the Drake Equations which - while properly explained - is misstated in the details. The equation is usually written: N = R* x fp x ne x fl x fi x fc x L where: N = The number of civilizations in The Milky Way Galaxy whose electromagnetic emissions are detectable. R* =The rate of formation of stars suitable for the development of intelligent life. fp = The fraction of those stars with planetary systems. Ne = The number of planets, per solar system, with an environment suitable for life. fl = The fraction of suitable planets on which life actually appears. fi = The fraction of life bearing planets on which intelligent life emerges fc = The fraction of civilizations that develop a technology that releases detectable signs of their existence into space. L = The length of time such civilizations release detectable signals into space. (Source: Seti Institute, http://www.seti-inst.edu/science/drake-bg.html) However, as given in the text of "Rare Earth" the formula is: N* x fs x fp x ne x fi x fc x fl = N This does not appear to be a big difference, however, the terms fi, fl, and fc are each mis-defined in the book. fi is defined as planets where life does arise, not intelligent life; fc as planets on which intelligent life emerges, not civilizations that develop a technology; and fl as percentage of lifetime of a planet that civilizations release detectable signals into space, not planets with life. This may seem nothing more then nit picking over details, but to me this is symptomatic of the entire work. If you can't even get a few simple 40 plus year old definitions right how accurate is the rest of the work? The belief that earth is the rarest of planets and then the selection of information to support that idea appears to be the main thrust here. Good science uses data to take you to a logical, fact supported conclusion, you get the reverse when to select facts to support a preconceived conclusion. Overall an unsatisfactory book.

NASA Will Never Like This Book!:
Peter Ward and Donald Brownlee have written a very thought-provoking book in "Rare Earth." They have, in fact, given voice to some thoughts that had occurred to me and to a lot of others quite some time ago - namely "Where is everybody?" Flying saucer enthusiasts and alien abduction aficionados aside, most of us who think about such things have wondered why no alien civilization's radio transmissions have not obviously reached planet earth by now if alien civilizations were so common. Also we are starting to wonder where life exists in our solar system outside of Earth. When I was in my teens I eagerly kept track of every launch of a spacecraft. I dreamed of even becoming an astronomer specializing in planetary geology. But my true love was biology and the thought of a possible alien biological system was fascinating. I was soon disillusioned. First the veil of Venus was lifted and where swamps and dinosaur-like creatures roamed in science fiction was a barren acid and heat scorched version of Dante's Inferno. Mars was also found to be a volcanic version of the earth's moon, except with weather (dust storms mostly), pole caps of carbon dioxide and water ice, and a very thin atmosphere. The temperature of close to 100 degrees F. below zero did not seem promising and still does not. Thus the civilizations of Mars envisioned by Lowell disappeared into the Martian dust (as they had started to even before the first space probes). Then the moons Titan (Saturn) and Europa (Jupiter) were proposed as abodes of life, however weird, and a Martian meteorite with strange "nano-bacteria" was brought out. The latter "nano-bacteria" have become dubious at best and the moons are looking less promising by the day. Titan may have such a smoggy atmosphere and be so cold as to be certainly questionable as an abode for life. In addition to this, recent reports indicate that Europa is covered with a layer of concentrated sulfuric acid (possibly from the neighboring moon Io, which has sulfur volcanoes on its surface) and hydrogen peroxide- not exactly a good place for living things! To top it off some scientists think that the ice on Europa may actually cover a sea of sulfuric acid with a pH close to 0! If we cannot find even primitive living things (bacteria, lichens, fungi) on other planets in our system we may have to face the fact that life, while it may exist on numerous planets, is not nearly as common and as accessible as some would have it and that "civilizations" are even less common. Why is this? Ward and Brownlee have provided detailed answers, which, even if their formulae are somewhat flawed (as one reviewer suggested), are persuasive. We have to keep in mind that we do not know how long civilizations last or how often they occur but do not develop our type of technology. We are up against billion of years of time and trillions of cubic light years of space. Star Trek aside, we are not even sure that interstellar travel will ever be possible, so we may never know for sure what is out there. As Ward and Brownlee point out, to even have a planet with the possibility of life we have to have several conditions met. First planets revolving around multiple stars probably do not last long because of tidal effects and if they do life might have to cope with radical changes in surface temperature. Given that, we still have a number of candidate stars and have even found a number of such stars with planets (most of which are huge, some even by Jupiter standards). We also need planets within a star's habitable zone (assuming the star is not unstable and lasts long enough for the development of life). Then contingency has to allow for the development of living forms sometime during the life of the planet. To get more complex life than bacteria we need several billion years and perhaps a large moon. It gets even dicier if we want intelligent life, and even then we may have intelligent ocean-dwelling creatures who never develop radio and thus may not be detectable. Even if radio waves are produced by a civilization, we need to exist ourselves within that civilization's survival time frame (or actually light years later). Ward and Brownlee have provided, I think, some very good reasons why we are unlikely to find multicellular life on nearby planets or advanced technologies on planets even around distant stars. Even if life is fairly abundant in the universe (and I think it probably may be), planets with life (even at the bacterial level) may not be anywhere near as abundant as lifeless ones. This is not a reason to embrace creationism, as some would have it, but is simply a property of our universe. While I wish it were not so, I fear we cannot argue with the logic of this- especially with the little evidence we now possess. Of course one cannot completely rule out the possibility that Ward and Brownlee have missed something, but that is a present a meager hope. Read this book if you are interested in why complex life may be uncommon in the universe.

Good book:
This book is somewhat difficult to read without proper background knowledge on some of these subjects. The authors have gone into details on some of the biological events that seem like gibberish to me and made very little sense. But the authors have made clear explanation of these events and provided evidence of their hypothesis. This book offered more than just a look beyond our Earth into the Universe, but rather a deep search within our Earth to find the answer of how life was created and evolved. Overall, the book is an interesting read on the combinations of geology, biology and astronomy. The difficulty of these subjects might have driven me away, and the advancement of science may put this book out of date very soon.