Willis - All these worlds are yours: the scientific search for alien life

ALL THESE WORLDS ARE YOURS

JON WILLIS

The Scientific Search for Alien Life

Copyright 2016 by Jon Willis.
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Library of Congress Control Number: 2015959236
ISBN 978-0-300-20869-6 (hardcover : alk. paper)

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To Rose and Sara.

Thank heaven for little girls.

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All these worlds are yours, except Europa. Attempt no landing there. Use them together. Use them in peace.

All these worlds are yours. The idea behind the title is that the search for life in the universe, both its practicalities and its implications, is accessible to anyone with an interest in science. The quote is taken from Arthur C. Clarkes 2010: Odyssey Two, and the use of a science fiction novel is deliberate.

Many of our preconceptions regarding alien life have been formed within the imaginations of writers and filmmakers. Such acts of creative imagination are often quite stunning and profound, but perhaps in ways that reveal the nature of the human creator rather than some unknown alien. One result, however, is that we all have some idea of what forms alien life might take, whether they will greet us or just eat us, or perhaps greet us then eat us.

Such ideas may well be anthropocentric, but when teaching the search for life in the universe to university students, I am always impressed by how eager the students are to move beyond popular imagination and how excited they are to realize that science fact outstrips science fiction in coming up with new and radical ideas.

Hence this book.

Sincere thanks are due to Joe Calamia and all of his colleagues at Yale University Press for bringing this book to you. Many others have provided much-needed help along the way, and I wish to thank them now.

Thank you to Florin Diacu and Paul Zehr at the University of Victoria for their invaluable advice and encouragement, which saw this book progress from an idea to a formal proposal.

Thank you to J. J. Kavelaars, Dave Patton, James DiFrancesco, and Christian Marois for supporting my book proposal and writing their encouragement to prospective publishers.

While many people have enriched this book through many discussions, I want to give particular thanks to Colin Goldblatt for his unceasing enthusiasm and ideas and for contributing much that has taken root in this book.

Many thanks to those who have read this book in part or full and been very generous with their comments and encouragements: Jillian Scudder, Kim Venn, Maggie Lieu, Trystyn Berg, Chelsea Spengler, Jericho OConnell, Jeremy Tatum, Colin Scarf, Sebastien Lavoie, Kyle Oman, and Michele Bannister.

Finally, many thanks to James Kasting and one anonymous reviewer who conducted formal reviews of this book and provided valuable and detailed feedback.

ALL THESE WORLDS ARE YOURS

Do aliens exist? Is there life beyond planet Earth? Well, yes, there is. Probably lots of it. How can I be so sure? Sure enough to start the book by telling you the answer? My answer is in large part based on a mathematical argument. The universe, as we shall see, is a very large placequite possibly infinite in size. We dont need to go into the math to understand that infinity means big. Big enough that, even though the possibility of something occurringsuch as lifemay be almost impossibly small, it must occur somewhere. The odds on your lucky lottery number may well be vanishingly small, but as long as the chance is not zero, if you play an infinite number of times, you are guaranteed to win. In an infinite universe, everything is possible. In many ways, though, this is an unsatisfying answerone that locates alien life in the distant recesses of what we imagine the cosmos to be. Much more interesting are the questions where is alien life to be found, what forms does it take, how does it live (and breathe), and how should we interact with it? But as we shall discover throughout this book, the answers to these questions are much more challenging to obtain than my rather facile yes in response to the question, do aliens exist?

What happens if I change the question slightly? Is there any scientific evidence that life exists anywhere in the universe beyond Earth? The answer to this questionat presentis emphatically no. It is possible that this is because life does not exist anywhere in the universe except Earth. But given my certainty expressed above, it is more likely that life indeed exists elsewhere in the universe, but we are yet to discover it. We havent yet searched, scoped, poked, or peered into enough places in the universe to have found it. For full disclosure, I should note that it is also possible that we already have the scientific evidence of life beyond Earth but that such evidence is not universally accepted as being proof positivemore later.

In large part this is because the challenge is great compared to our current resources. Despite the claims of UFO enthusiasts, alien life has not spontaneously appeared on our doorstep. Alien life also appears to be beyond the current reach of our telescopes and space probes. In a world of limited scientific resources, we have to decide exactly where to search and how to search in order to achieve the best chance of success. Scientists refer to the ideas that underpin these efforts as astrobiology. The science of astrobiology has three main goals: to understand the conditions necessary for life on Earth (and possibly the conditions required by life in general), to look for locations in the universe which supply these conditions, and, finally, to detect life in these locations. At present we have discovered a great many potential habitats for life, planets and moons in our solar system or planets orbiting distant stars. Some of these new worlds replicate in part conditions we encounter on Earththe only location in the universe where we know that life exists.

At this point, the keen reader will protest as to why we use life on Earth as a template for the search for life in the universe. What if life on Earth represents only a tiny fraction of the range of properties displayed by life beyond Earth? Is our search too narrow in scope? Do we run the risk of missing truly alien life because we dont know how to recognize it? Once again, the answer is clearly yes. By starting with life on Earth and working outward, our search will not discover all possible life-forms. We will overlook the consciousness of free floating asteroid-like organisms and other unthought-of possibilities. But you have to start somewhere. The only life we know is that of Earth. By using this as a starting point, we can speculate about the kinds of life processes that might occur on planets similar to Earthand by this I mean those that have a solid surface, an atmosphere of some kind, and possibly a range of chemicals in the liquid state. The only thing I can guarantee is that the more we look, the more we will learn about life and its possibilities. Okayprotest postponed? Lets proceed.