The Search For Life On Mars [Paperback]

Malcolm Walter (Author)

Book Description

Publication Date: September 20, 2000

Hidden beneath the sterile surface of Earth's neighboring planet may be the keys to unlocking the origins of life in the universe. An expert on extreme-life environments, Malcolm Walter argues that the best place to find evidence of life on Mars is out of reach of telescopes and space probes--it's in the rocks and subsurface water of the Red Planet. In this engaging and authoritative book, Walter unveils his dramatic plan-already adopted by NASA--for finding these elusive traces of life.

Editorial Reviews

Amazon.com Review

Who's afraid of little green men these days? We've got more pressing (and realistic) worries now, but recent evidence points to the red planet as a possible source of living matter, so while we might not have to worry about the war of the worlds, it does behoove us to be neighborly and check it out. Astrobiologist Malcolm Walter wrote The Search for Life on Mars to explain what we know and what's at stake in this interplanetary reconnaissance mission. His writing is relaxed and personal; he shares his early experiences observing the space program with the readers and builds in us a sense of the magic felt by the pioneers in extraterrestrial exploration. He goes on to describe our current state of knowledge--and ignorance--about life elsewhere and on Mars in particular, then explains what we're currently doing to investigate and why.

The fabled "Martian meteorite" renewed interest in both Mars and the search for alien life, and Walters tells us its history and probable origin, though much still remains unknown. The excitement of working with NASA comes through in his writing about his own work; it's fascinating to read of space research divorced from the old context of nationalistic pride. Walters ends the book with a beautiful, lucid description of what the first Martian explorers will see, and argues gently for the importance and relevance of this work to our lives and those of our descendents. --Rob Lightner --This text refers to an out of print or unavailable edition of this title.

From Publishers Weekly

If all goes well, in 2003 two highly evolved descendants of the Sojourner "rover" that scuttled around Mars in 1997 will return to the planet and collect new samples. NASA scientists will then scrutinize these souvenirs for evidence of extraterrestrial life. But considering the cost of the trip, where should NASA concentrate its search? A paleontologist at the University of Sydney, Australia, who has been involved with NASA's Mars missions for more than a decade, Walter analyzes the conditions surrounding the emergence of life on earth to suggest the most likely locations of Martian fossils. Three and a half billion years ago, water was as plentiful on Mars as on earth. Scientists believe that vast quantities of water (the prerequisite for life as we know it) still exist on Mars, not only at the poles but also in an underground layer of permafrost. And in the last few decades, scientists have discovered vast numbers of micro-organisms living inside earth's rocks, far underground and around thermal springs, environments that were once considered too inhospitable to support life. Thus, Walter proposes that, despite Mars's harsh climate, fossils and living organisms might be found in three environments: former lake beds, spring deposits and microbe-produced ore deposits similar to the silver, lead and zinc deposits in northern Australia. Though Walter's concluding section on the importance of space research is weak and his exposition occasionally rambles, his chapters on paleontology, microbiology and geology are refreshingly lucid. Illustrations not seen by PW. (Nov.)
Copyright 1999 Reed Business Information, Inc. --This text refers to an out of print or unavailable edition of this title.

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Product Details

• Paperback: 200 pages
• Publisher: Basic Books (September 20, 2000)
• Language: English
• ISBN-10: 073820367X
• ISBN-13: 978-0738203676
• Product Dimensions: 8.2 x 5.4 x 0.4 inches
• Shipping Weight: 8 ounces (View shipping rates and policies)
• Average Customer Review: 4.5 out of 5 stars  See all reviews (2 customer reviews)
• Amazon Best Sellers Rank: #3,439,731 in Books (See Top 100 in Books)

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5 of 5 people found the following review helpful:

5.0 out of 5 stars Not as easy as you might think, May 25, 2001

By 

Duwayne Anderson (Saint Helens, Oregon) - See all my reviews
(REAL NAME)   

This review is from: The Search for Life on Mars (Helix Books) (Hardcover)

This book is a little like "Here be Dragons," (Koerner, LeVay, Oxford University Press, 2000) and "Rare Earth," (Ward, Brownlee, Copernicus, 2000) except that it is more focused and specific than the others. While Koerner, LeVay, Ward, and Brownlee consider the possibility that life exists outside the solar system, Walter limits the scope of his book to the question of whether microbes exist, or once existed, on Mars.

Life outside of earth has never been unambiguously observed and verified. Consequently, discussions about the possibility of life beyond earth inevitably begin with thoughts about how life originated here. There seems to be an emerging sense that life is the result of a universe that is naturally self-organizing (Stuart Kauffman is in this camp. See his book "At Home in the Universe, Oxford University Press, 1995). According to this point of view, life is all but certain to arise on any planet having the basic chemicals and physical conditions found on earth 4 billion years ago. Given this hypothesis - that life arises quickly and naturally in the proper environment - it's natural to ask if any other planets in the solar system have (or had) the necessary ingredients. If they did, we should look to see if life evolved there. Since there is growing evidence that Mars had a distant past with some of these conditions, it seems more and more important that we look for life on Mars. Finding evidence of life there would buttress the concept that life readily evolves given the proper environment. Obviously, if that's the case, it holds enormous consequences for modern science.

Walter has a nice chapter on the tree of life, and describes recent information showing that "all the lowest branches of the tree are occupied by hyperthermophiles." The discovery that life exists on earth under extreme conditions (like those of deep-sea thermal vents) has increased the hope among scientists that it might also have evolved and flourished on Mars many thousands of millions of years ago. He also shows how genetic transfer between species happens today, and was probably common among our earliest ancestors, so that the whole concept of a "tree of life" becomes somewhat tangled during the earliest stages of the evolution of life. Instead of a tree, the topology looks more like a web, with the roots of the tree (consisting of Bacteria, Eucarya, and Archaea) rising out of this web.

The expectation of finding evidence of life on Mars depends on the type of environment that Mars supported in the distant past, and the circumstances under which life arose on earth. It also depends on how easy it is to ascertain the evidence of fossilized ancient microbial life. It turns out that identifying evidence of microbes in very old rocks is a pretty hard thing to do. To illustrate this, Walter describes the difficulty of identifying stromatolites in ancient rocks. This was new information for me, and a real insight into the nuts and bolts of making these sorts of identifications. I'd thought that stromatolites were easy to identify, but in the very oldest rocks, they're not. When identifying stromatolites in rocks 3000 million years old, there can be (and often is) a great deal of controversy regarding the conclusion. Walter's point in making this so clear is that stromatolites are large colonies of microbes, yet even they are not unambiguously identified in the oldest rocks. The problem of identifying evidence for individual microbes in rocks 3000 to 3500 million years old is even tougher. The point being that even with Martian rocks in our hands, it's not going to be easy to affirmatively state whether there is evidence of ancient life on Mars.

To drill the point home, Walter points to the fact that we do have chunks of Martian rocks on hand, in the form of bits and pieces that have been blasted off the Martian surface by meteorite impacts. Walter describes in detail the scientific examination of some of these rocks, and one, in particular, identified as ALH84001. This meteorite made world news when a team of scientists reported finding evidence of ancient microbes buried inside it. Walter describes the initial reports, the objections, and the eventual state of limbo in which these conclusions came to rest. This helps set the tone for expectations regarding the difficulty against which such analysis will proceed even when we manage to return samples from the Martian surface using spacecraft.

In describing how scientists make conclusion about the presence of microbes in ancient rocks, Walter does a real service by illustrating the importance of convergent evidence. Identifying ancient microbes involves more than one type of observation. It involves many types of converging data, including visible observations of deposits in rocks, the types of rocks involved, and things like carbon isotope ratios (not to be confused with carbon 14, which decays far to quickly for analysis in 3000-million-year-old rocks). Along these lines, I noticed a recent article in Photonics Spectra (May 2001) describing the use of Raman imaging to identify microfossils - another tool, in the search for the ancient life on earth, and possibly on Mars.

The book ends with some very informative discussions about proposals for future landing sites on Mars, for sample analysis and/or return.

This is a very informative book, with useful insights into the way science works, complete with several pages of color plates, a useable index, and short list of further reading material. If you are interested in what NASA does, and how the scientific search for life on Mars is (and will be) carried out, I think you will like it. I certainly did.

4 of 4 people found the following review helpful:

4.0 out of 5 stars Looking for life on Mars, April 10, 2000

By 

Steven Belasco (Greenburgh, New York) - See all my reviews
(REAL NAME)   

This review is from: The Search for Life on Mars (Helix Books) (Hardcover)

Malcolm Walter has written a fascinating guide to where we should look for current or past life on Mars. As a non-scientist I was not quite sure what to expect in buying this book, but what I found was a thoughtful discussion of how one scientist would explore the red planet for signs of life. Walter gives a short, understandable review of the scientific discoveries to date from the past NASA missions as a prelude to what to expect in the future. However, his background is in palaeobiology on Earth, which I learned is the study of fossilied life. Having absolutely no knowledge of this field myself, I sometimes felt a little lost in his technical discussions and wasn't always sure that I wanted to know as much as he told me about microbe fossils on Earth. Nevertheless, the thrust of his arguments and points he made were all clear. The heart of his case is that there is a lot we can learn from palaeobiology on Earth that should inform how we search for life, which may very well only be fossilized former life, on Mars. The importance future extensive scientific exploration for signs of past or present life on Mars is also well made. Overall, this short book (170 pages including the index) is worth the the time, and for a layman the effort, for anyone who has even a passing interest in this subject.