Book Review: If the Universe Is Teaming With Aliens… Where is Everybody?
A review of If the Universe is Teaming With Aliens…Where Is Everybody? Seventy-Five Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life by Stephen Webb. Second edition, 2015 Springer.
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The Fermi Paradox: Where Is Everybody?
This book documents and comments on 75 potential solutions or answers to the Fermi Paradox on why we haven’t found proof of intelligent, extraterrestrial life yet. The Fermi Paradox is based on the following generally accepted views on the likelihood of ETI (Extraterrestrial Intelligence) in the Milky Way galaxy:
- The Milky Way contains about two hundred billion stars.
- These presumably have planets totaling in the hundreds of billions at least.
- Billions of these planets should have suitable conditions for life to exist.
- Life and eventually Intelligent beings should have evolved on some of these habitable planets, if only a small percentage.
- Given the age of the universe, some of these civilizations could be millions or perhaps billions of years older and thus more advanced than us.
- It would only take a few million years traveling at a fraction of the speed of light for some of the civilizations to colonize the entire galaxy.
This leads to the question of why we don’t see obvious evidence for ETIs. Given the above assumptions, they should exist in some number in the galaxy and should’ve been here by now. They could have colonized the earth or solar system long ago if they wanted to. So as Enrico Fermi asked, “Where is everybody?” That is the Fermi Paradox.
This “paradox” has gotten more acute in recent years in some ways. Astronomers the past couple decades have now discovered thousands of planets orbiting nearby stars. It seems perhaps nearly all stars have at least one, probably multiple planets orbiting them. Hundreds of planets discovered so far are in the “habitable” zone where liquid water is a possibility on their surface. So it seems that assumptions or claims 1-3 above are now confirmed. There seems to be, by extrapolation, hundreds of billions of planets in the Milky Way and hundreds of millions of potentially “habitable” planets in our galaxy alone.
On the other hand, SETI (the search for extraterrestrial intelligence) has been scanning the sky searching for radio signals from ETIs for decades and still hasn’t heard a peep. The Great Silence. We still have no proof of any life existing at all besides on earth, let alone advanced ETI races capable of colonizing the galaxy. We haven’t found proof of ETI colonization or even visitation of our solar system. Why isn’t belief #4 above at least confirmed yet especially since 1-3 above have recently been confirmed? And if #4 is true, #5-6 seems inescapable. Where is everybody? What’s wrong with this picture?
The Author And His Approach
The author, Stephen Webb, is a theoretical physicist by training (PhD, Manchester). Webb has been collecting proposed solutions to the Fermi Paradox for years. This second edition of the book contains 75 (the first edition had 50 and a future third edition will contain 100 I believe). This book provides a good, broad overview of the solutions to the paradox and the scientific issues involved.
The approach to the question of extraterrestrial life and ETI in the book is strictly a scientific one. This is understandable given the author’s background and the fact that proof of the existence or non existence of life elsewhere in the universe and of ETI is a strictly empirical one, thus a scientific one. The two possibilities can only be resolved by either scientific investigation (SETI, planetary probes, etc) or ETI making their presence obvious. Either possibility regarding life and ETI elsewhere (or not) in the galaxy has profound philosophical, theological, and scientific implications that interest me and many others. He doesn’t address philosophical issues here much admitting, “I find most philosophy books tough going.” So the book focuses on the scientific issues that bear on the question and with each proposed solution.
Contents
The first two chapters deal with the question of extraterrestrial life and the Fermi paradox. The next three chapters are on solutions to the paradox. These various answers or solutions are put into 3 categories (a chapter for each) based on the solution’s conclusions.
The first category (chapter 3) are solutions that argue that ETIs are or already have been on earth (UFOs, ancient astronaut, Zoo Hypothesis type answers). These are the most popular with the general public. The second category (chapter 4) are solutions that argue that ETI exist, but we just haven’t found definitive scientific evidence yet (such as alien artifacts, radio signals, or chemical signatures in exoplanet atmospheres). We’re on it, it’s just a matter of time now (‘absence of evidence is not evidence of absence’). The third category of explanations (chapter 5) conclude that the reason we don’t see any good evidence of ETIs is unfortunately the scientific evidence suggests they probably don’t exist. These solutions or answers conclude that there are significant problems with assumptions 4-6 of my statement of the paradox above. Chapter 6 is the author’s favored solution.
The book contains footnote references in the back and references to sources used. These contain plenty of references for further research and I have started using it to track down interesting material that bear on this issue I wasn’t aware of.
The text dealing with each solution ranges from a couple paragraphs to several pages. Webb does a good job of spending enough time when needed to explain the scientific issues and evidence that bear on the issues the solution brings up or is based on. These longer passages include the origin of life, galactic habitable zones, continuous habitable zones, the evolution of intelligence and consciousness, issues in interplanetary travel, etc. He also usually does a good job of explaining the strength and weaknesses of each solution of the paradox.
In short, this is a good book introducing the subject and the basic scientific issues involved. I found it a responsible, fair, and even-handed treatment. I recommend it for those who are looking for a good overview of the subject.
In writing a review of the book I started going through the three categories of solutions and some specific examples. This made it way too long. I will look at some of the major issues related to the Fermi Paradox in more detail in future posts. I plan on looking at the three categories one at a time as a general overview and then looking at more specific solutions that I think are the most important, plausible, and/or interesting to me as this is a major topic of interest to me.
An interview with Webb about his book:
[Event Horizon is a YouTube Channel that focuses on space exploration and the search for extraterrestrial life that I recommend. It has numerous interviews of scientists and researchers with different views dealing with these subjects.]