Enrico Fermi, one of the most renowned physicists of the twentieth century, was the father of the Manhattan Project, and, I suppose, the Nuclear Age as well.
Of course, if you watch Ancient Aliens, then you know him for the famous Fermi Paradox, which paraphrased is, “If they exist, then where is everybody?” meaning that if aliens exist, then they should be here by now. The state of the universe, even the small part that is our own tiny galaxy of 100 billion or more stars, some of which are a billion or more years older that we are, yields the probability that life evolved and advanced to a state where galactic travel existed for Them long before we emerged from less sophisticated primates, not monkeys, evolution doesn’t say that, it says that somewhere back there, we and they have a common ancestor who was neither a monkey nor a homo sapiens. The advanced ones, should have been here by the time Enrico and his famous luncheon buddies, Von Neumann, Teller, and others discussed Their existence at Los Alamos Laboratory, in the 1950’s. Now stop and focus more on the number 100 billion and the possibilities, even at low incidences of Earth-like planets, and they aren’t low; they are quite high.
Of course his Nobel Prize winning associates began to offer solutions to his paradox. I don’t know how many lunches it took to evaluate this topic, nor how many hours they overran their allotted breaks, but high level scientists like that are paid to think creatively and thereby extent the horizons of knowledge for our species.
While we’re on Fermi, he was known for generating Fermi style questions and offering multi-factor solutions, where most of the factors are probabilities, in other words a quick linear shot of conditional probability. In an example from the book, Where is Everybody, to be discussed later, Fermi asks his class, “How many piano tuners are in Chicago?” The answer is N = f1 x f2 x f3 … fn x B, where B = population of Chicago, f1 = the inverse of average family size, f2 = a guess, 1 in x families owns a piano (e.g., 1 in 20 families owns a piano, ration =1/20), and so on: how often are pianos tuned, how long does it take, how many can the tuner do in a cycle, etc.
The Drake equation is a Fermi style answer to the question: How many communicating civilizations exist? This could also be further limited by asking how many exist within 1000 light-years of Earth.
In my library are two books that address the Fermi Paradox. Both are worth reading.
Where is Everybody by Stephan Webb provides fifty solutions to the Fermi Paradox. It is a delightful book that delves into the major issues that must be overcome for intelligent life to develop. Webb starts his book with an enlightening bio ofEnrico Fermi, then he discusses several paradoxes and how some might be resolved. From there he proceeds to discuss the fifty solutions. Each solution makes a nice bedtime read and provides a quick summary of a scientific issue related to the existence of extraterrestrials, and even our future existence, in some cases. A neat little embellishment is a quote from someone famous at the start of each section. Regarding this subject, I believe Jung said it best, “When facts are few, speculations are most likely to represent individual psychology.”
Some of Webb’s solutions are humorous (the aliens are here and they are Hungarians), but most are thought provoking, and by the end of the book, you have a good feel for the complex issues of life in the universe.
The other book, Alien Invasion by Travis Taylor, PhD (with multiple Masters) and Bob Boan PhD, takes a different approach, one that suggests it’s not whether they will come, but when. His book is the basis for a TV presentation, When Aliens Attack, on The National Geographic Channel. The first part of this book uses the Drake equation and recent Kepler Mission data to estimate the number of space traveling civilizations that are likely to be within striking distance of Earth. I found this part interesting; others thought the math too heavy. The rest of the book deals with survival tactics we might use once these hostile travelers arrive. The whole thing provides a good basis for building a sci-fi plot that tomorrow morning may no longer be science fiction.
Taylor’s book gives you a good sense for how many possible civilizations are out there and what could happen once one of them travels to Earth. Webb’s book explains why that encounter may never happen. Both are worth reading.