Of Fermi and Paradox

Before considering the merits of the various proposed solutions to the Fermi paradox, this chapter presents some of the background. I first give a short biography of Enrico Fermi himself, focusing on just a few of his many and varied scientific accomplishments. I mention only those contributions to science that I refer to in later sections of the book. I ignore, for example, his contribution to cosmic ray physics: Fermi was the first to propose a realistic model for explaining the origin of the high-energy particles that bombard Earth from space. This work is honored by the naming of NASA’s satellite mission for investigating cosmic rays—the Fermi Gamma-ray Space Telescope. Indeed, Fermi’s scientific achievements were so numerous that the Fermi Space Telescope is only the latest in a variety of things named after him. Fermilab, in Batavia, IL, is one of the world’s leading centers for particle physics; the element with atomic number 100, which was first synthesized in 1952 in a hydrogen bomb explosion, is called fermium (Fm); the typical length scale in nuclear physics, 10−15 m, is called the fermi; 8103 Fermi is a main-belt asteroid and Fermi is a large crater on the far side of the Moon; several members of the Enrico Fermi Institute at Chicago University have won Nobel prizes. For more details of Fermi’s life, both inside and outside science, I recommend the interested reader to the biographies of Fermi listed in the References. I then discuss the notion of paradox, and briefly look at a few examples from various fields. Paradox has played an important role in intellectual history, helping thinkers to widen their conceptual framework and sometimes forcing them to accept quite counterintuitive notions. It’s interesting to compare the Fermi paradox with these more established paradoxes. Finally, I discuss how the Fermi paradox itself—where is everybody?— came into being. It’s worth noting that some people argue that this is neither a paradox nor is it Fermi’s. Nevertheless, we shall see that Fermi’s question can be cast into the shape of a formal paradox (if you feel the need to do so) and I explain how Fermi’s name came to be attached to a paradox that is older than many people believe.