Life Everywhere: The New Science Of AstrobiologyDavid Darling | 2001-04-05 00:00:00 | Basic Books | 224 | Astronomy
The scientific story of the coming centurythe inevitable discovery of life on other planets and what it will mean for our understanding of earth.
To many people, the main question about extraterrestrial life is whether or not it exists. But to the scientific community, that question has already been answered: It does. So confident are scientists of the existence of life on other planets that they've invested serious amounts of money, time and prestige in finding and studying it. NASA has started an Institute of Astrobiology, for instance, and the University of Washington, Seattle, began in September 1999 to accept graduate students into its Department of Astrobiology.
Life Everywhere is the first book to lay out for a general reader what the new science of astrobiology is all about. It asks the fascinating questions researchers are asking themselves and one another: --What is life?
--How does it originate?
--How often does life survive once it arises?
--How does evolution work?
--What determines whether complex or even intelligent life will emerge from more primitive forms?
--Informed by interviews with most of the experts in this nascent subject, Life Everywhere introduces readers to one of the most important scientific disciplines of the coming century.
Are we alone? As the search for extraterrestrial intelligence comes more and more into the mainstream, scientists like David Darling step up to explain what we know and what's possible. His book Life Everywhere explores the history and current state of the field called, perhaps unfortunately, astrobiology. Devoted neither to organisms skimming the sun's surface nor to possible signs of intelligence among celebrities--though not explicitly rejecting these phenomena--astrobiology is concerned with the basic questions of life: What is a living organism? Is it common, or likely, elsewhere in the universe? Is it worth trying to communicate across light years? Darling, an astronomer and science journalist, has a knack for explaining complexities and fine details that carries his prose forward where other authors have foundered; the reader is swept up in the enthusiasm of the researchers Darling describes. Writing of the astronomical search for signs of life far off in the galaxy, he captures the thrill of this work:
Their efforts will revolutionize astrobiology, more so perhaps than spacecraft parachuting down out of the orange sky of Titan or roving the rock-strewn deserts of Mars. The world-shaking headlines of the next twenty years will likely come from giant instruments, on the ground and in Earth orbit, gazing with far sight at the planetary systems of other stars.
Since most research germane to the field has been done here on Earth, Darling explores such hot topics as heat vents and other geothermal mini-biomes, meteoritic dissection, and, of course, SETI's radio telescope arrays. Mars, Venus, and the moons of the outer planets are all major characters, and their stories will reinvigorate most readers' excitement about the prospects of having neighbors just down the cosmic street. Ending with a set of hypotheses and brief explorations of their ramifications if shown to be true, Life Everywhere is an outstanding and thought-provoking look at what could ultimately be the most world-shaking research ever conducted. --Rob Lightner
Reviews
Life Everywhere was undoubtedly a much more groundbreaking book when it was published in 2001 than it is today. On the one hand, many of the ideas about the probable inevitability of extraterrestrial life which Darling was popularizing still seem to be in vogue today. Most likely, extraterrestrial life will be found to be carbon-and-water based on an earth-sized planet located around a star similar to our sun and located within a distance from it known as the habitable zone. A large moon and a Jupiter-sized planet within that solar system would greatly facilitate matters in a favorable way for life to arise. But cases can be made for exceptions to all these conditions. One thing that really dates this book however is a section near the end where the author looks forward to the advances in knowledge which we will gain by space missions in 2004, 2006, etc. I haven't been a follower of astrobiology up until recently, but I don't think these missions have revealed anything earthshaking or I would have heard about it. One discovery that has been momentous, of course, is the recently announced(April 21st, 2009)finding of an earth-sized planet 20 light-years away. It seems likely there are more to come, and that there will be a new crop of astrobiology books, inspired by this discovery, to come also. Another book on the subject of extraterrestrial life which is much more recent than Life Everywhere, is one called Beyond UFO's: The Search for Extraterrestrial Life and Its Astonishing Implications for our Future, by Jeffrey Bennett. Don't let the sensational sounding title fool you. This book was written by a scientifically trained writer of an astrobiology textbook and is endorsed by scientists in the field. In my opinion, besides being more recent, it provides more detail and a more systematic and comprehensive view of the field, although, of course, it predates discovery of the earth-size planet. Bennett, like Darling, also takes some time out to lecture a bit about the negative effects on science of creationism and intelligent design. This seems to be standard procedure in popular science books these days, and I'm not personally convinced these warning labels are warranted. Be that as it may, both books are good, but if I had to choose between the two, I would pick the Bennett book.
Reviews
I think this is a good book to read after reading "Rare Earth". The writing style is definately more casual and as if you are inside the mind of Darling, compared to the more "here's the information" style of other books. It took a while to get used to it, but in the end it was a nice change to have that type of commentary.
The book does a good job of covering the various areas of astrobiology, however, I think Rare Earth probably does a better job in talking about a few things. This is one reason why I recommend reading Rare Earth first. The other reason obviously being the critique of the Rare Earth hypothesis, and one section that totally rips apart Guillermo Gonzalez's "hidden agenda" as he calls it. The two books are kind of like listening to a debate, and both seem to have good arguments in some place but slightly unreasonable arguments in other places. Overall it gives you a good feel for where we stand today in our knowledge and what we can reasonably assume about the possibility of life elsewhere (microbial or complex).
At times I did feel like Darling was being a bit unfair to the Rare Earth authors - attacking them or the book a bit too much. But in the end he settled down.
Overall a good book that complements Rare Earth well.
Reviews
Two things have happened in recent years to persuade most scientists that life beyond earth is not just possible, but likely. Indeed some people, including myself, believe there is, as the title of David Darling's book has it, "Life Everywhere."
Well, not in the center of the sun or on the surface of a neutron star--at least not life as we know it.
"Life as we know it." This is an important phrase that comes up again and again in discussions about astrobiology. "Life as we know it" means life with a carbon base and liquid water. David Darling considers silicone-based life and even life forms so bizarre that we wouldn't recognize them if we saw them, but basically he sticks with life as we know it in this very interesting answer to those who think that life in the universe is rare.
The two things:
(1) The discovery of extremophiles, bacteria that live in sulfurous hot springs, deep inside the earth, and at the bottom of deep oceans. Instead of deriving their energy from the sun, they are able to use heat coming from within the earth to metabolize.
(2) The discovery of scores of planets (albeit not earth-sized planets--yet) revolving around other stars.
What the first discovery means is that life doesn't have to exist or begin in conditions such as there are or have been on the surface of the earth, but can thrive in places previous thought hostile to life. That opens up a whole lot of the universe to life including parts of our solar system previously thought inimical to life, such as in an ocean under the icy crust of Europa or beneath the inhospitable surface of Mars. And the fact that planets are now clearly plentiful means that there are numerous places for life to develop.
Darling, who is an unusually lucid writer and a man who gets to the bottom of things, begins with the nitty-gritty problem of just how to define life. If you haven't been introduced to this strangely knotty problem, this book may open your eyes. Do we consider reproduction, metabolism, growth, etc. in our definition? And which of these elements are essential and which are not? The postmodern definition now preferred by most people I have read is "undergoes Darwinian evolution." Is that adequate? Is that the essence? Darling puts all the cards on the table and lets you decide.
Next Darling recapitulates ideas about how life began. The main new idea is that life may be an inevitable consequence of the nature of matter and energy. It appears that matter is self-organizing. Darling reviews the ideas of how lifeless matter might replicate and how cells might develop from various molecules and water. These "leaky membranes" could be the precursors of the first biological cells. (p. 40)
He goes on to make the case for a universe with abundant life. But along the way he presents a blistering critique of Rare Earth: Why Complex Life Is Uncommon in the Universe (2000) by Peter D. Ward and Donald Brownlee, in which it is argued that the circumstances that allow life are rare and that those circumstances as seen on earth are unlikely to be replicated anywhere else. Darling not only utterly destroys their argument, point by point, but even shows that part of the reason that it was advanced was because they were under the influence of one Guillermo Gonzalez, professor of astronomy at the University of Washington, who is also a creationist with the usual supernatural agenda.
This was bombshell to me. But Darling shows that nearly every argument that Gonzalez makes is designed (pun intended) to discredit the idea that there is life anywhere but on earth. On page 112, Darling refers to an article entitled "Live Here or Nowhere" co-authored by Gonzalez for a publication called "Connections" published by Reasons to Believe, Inc. of Pasadena, California, whose mission is "to communicate the uniquely factual basis for belief in the Bible." The article concludes, "The fact that the sun's location is fine-tuned to permit the possibility of life--and even more precisely fine-tuned to keep the location fixed in that unique spot where life is possible--powerfully suggests divine design."
A couple more points:
First, Darling argues that life forms on other worlds, however dissimilar their chemistry, are likely to be familiar to us in the sense that if there is an atmosphere, some will have wings, and if there is an ocean, some with have fins, if there is a solid ground to walk upon, some will walk and run, and if there is light to see, some with have eyes. This idea of "convergence" is dictated by the laws of physics which requires evolutionary adaptations to take forms that work efficiently within certain environments. Of course if the life forms we eventually discover exist in great dust clouds, their adaptations may be very dissimilar and surprising. Even on solid ground here on earth some run and some hop, some crawl and some slither.
Second, since it is now known that bacteria spores can exist more or less indefinitely (some have been revitalized after hundreds of millions of years of dormancy: see page 150), the once discredited idea of panspermia, namely that life originated elsewhere in the universe and arrived here as spores, has been rejuvenated. Personally, I've always liked this idea championed by Fred Hoyle and Chandra Wickramasinghe; however this book has convinced me that life could arrive from without or develop from within. Either way (or both) seem likely to me.
Reviews
This book is actually in the form of a long essay defending the hypothesis that life, at least in microbial form, is widespread in the Galaxy.
The author starts by trying to define life. Is it replication? Evolution? Metabolism? Next, he discusses the question of the atmosphere of the early Earth. A reducing atmosphere might produce complex organic molecules in some warm little pond. But the Earth is unlikely to have had such an atmosphere then. That leads to the question of where life originated. Near ocean vents, or on (or just under) the ocean floor? And when life originated. Over 4 billion years ago? When the Earth was still being bombarded by bolides?
The author then discusses meteorites, along with the possibilities for them having brought organic molecules (or even life) to Earth. After that, there's some material on extrasolar planets, including "hot Jupiters," which may migrate right through a stellar system, wiping out all the rest of the planets in it.
A very interesting section is Darling's critique of Ward and Brownlee's book, "Rare Earth." That book contains the view that although microbial life is probably widespread on other worlds, multicellular life (and especially intelligent life) will prove to be rare. Actually, that view, while a minority one, is unremarkable. After all, there is good evidence that unicellular life originated rather quickly on Earth while multicellular life took quite a bit longer. But Ward and Brownlee go further than that, claiming that several things about Earth are special and unusual: the Moon, the exact spacing between catastrophic events, being in the right part of the "habitable zone," having Jupiter to shield it from heavier bolide bombardment, having a high metallicity Sun, having plate tectonics, and being in the right part of the Galaxy! Darling presents interesting rebuttals to these points. And he finishes the chapter by pointing out that a collaborator of Ward and Brownlee, Guillermo Gonzalez, keeps finding signs that the Earth is unique. Darling asks if Gonzalez is letting his religious beliefs influence his scientific views (Gonzalez says that his views that life's origin involved the personal involvement of a supernatural creator have motivated his science and vice-versa). Um, that is a good question. Still, I wonder if that's altogether fair. Ought we ask about Simon Conway Morris, whose religious beliefs support his views on convergence? Or about, say, Fred Hoyle, with his views on panspermia? Or about Freeman Dyson, whose scientific ideas seem rather independent of his religious views? Or about, um, me?
In any case, Darling continues with the debate between Stephen Jay Gould and Simon Conway Morris. Gould argues for divergionism, and says that were we to "replay the tape of life," the odds are that the chordate worm that first incorporated what became the human body plan would have been lost and there would have been no humans. Conway Morris argues for convergionism, and says that no matter what specific species survive, niches tend to get filled. And that means that some creatures very much like humans would have evolved had we replayed that tape. Darling agrees, and adds that even intelligence appears to be convergent.
The author then tells about upcoming space missions to look for life in the solar system and to discover more about extrasolar planets.
Darling concludes that life is a universal phenomenon, life's most important characteristic is to engage in Darwinian evolution, life originates on planets and moons, planets are very common, the evolution of life involves contingency and convergence, and life can be both planet-wide and refugial. But he says that future events may get us to change our minds on some of this. What if we find life on Mars? Or find definitive evidence that Mars has always been sterile? Or find life (or even find complex life) on Europa? What if we spot an atmosphere on an extrasolar planet that suggests life abounds there? What if we find bacteria in interstellar space? What if we find life based on silicon instead of carbon? Or make contact with extraterrestrial artificial life? And while it might be tough to verify it, what if we were to discover that there is no other intelligent life (or no other life) in the universe?
While it wouldn't surprise too many people, the author says it would also be significant were we to verify the existence of a very deep, hot biosphere such as the one Thomas Gold has proposed.
This book is easy to read and informative. I recommend it.
Reviews
This is one of eight books on Astrobiology which were rushed out after the publication of Joseph's revolutionary and ground breaking text, in May of 2000. Like the other seven competing volumes, this text differs from Joseph's, in that it strictly holds to the "party" line, as approved by the United States government, and repeats, without any critical analysis, mainstream scientific dogma. Now, don't get me wrong. Although he avoids mentioning Joseph's book--which clearly triggered the writing of his own--Darling does an otherwise good job of provding a "politically correct" overview of the status quo. If you are interested in the views held by mainstream, government funded scientists, this is the book for you.
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