Quantifying SETI

It should come as no surprise to readers of QEX that the scientific Search for Extra-Terrestrial Intelligence (SETI, sometimes called the search for the ultimate DX) was initiated by, and is still largely conducted by, radio amateurs. The world’s hams instinctively understand the nature of electromagnetic communications, as well as the nature of the “free space” (or “aether”) that fills the void between the stars, and forms a transmission medium for our favored photons. If asked to identify one radio amateur whose contributions to SETI were the most significant, I would not hesitate to name the late Dr Philip Morrison, W8FIS, the father of modern SETI science.1 Institute Professor Emeritus of Physics and Astronomy at the Massachusetts Institute of Technology, Phil Morrison was a distinguished theoretical astrophysicist, and a pioneer in the search for extraterrestrial intelligence through radio communication. He authored scores of books, produced countless television documentaries and lectured tirelessly around the world, despite the physical limitations imposed upon him by post-polio syndrome. Phil Morrison passed away quietly at his modest home in Cambridge, Massachusetts, in April, 2005 at the age of 89; but not before inspiring a whole generation of scientists (including me) to ask the difficult questions and then attempt to answer them. It is to Phil Morrison’s memory that this article is dedicated, and it is with his most important publication that it deals.