Communication with Extraterrestrial Intelligence

This article, written by Lambros D. Callimahos and originally presented at the 1965 IEEE Conference on Military Electronics, explores the scientific and theoretical framework for establishing communication with extraterrestrial intelligence. The author posits that the existence of extraterrestrial life is statistically probable, citing calculations by astronomers such as Sir Bernard Lovell and Dr. Frank D. Drake. The text focuses on the technical challenges of interstellar communication, specifically the selection of a frequency for transmission. It highlights the 1420.4 megacycles per second frequency—the radiation frequency of atomic hydrogen—as a logical choice for interstellar signals, as it is a natural phenomenon that would be understood by any civilization with radio theory knowledge. The author discusses Project Ozma, an early attempt to detect such signals, and explores alternative communication media, including masers, lasers, and the theoretical modulation of neutrino beams. A significant portion of the article is dedicated to the methodology of 'inverse cryptography,' where the sender designs a message to be easily understood by a recipient without a shared cultural or linguistic background. The author provides examples of how such a message might be structured using binary digits to convey mathematical concepts, physical descriptions of the senders, and even the chemical structure of their life forms. The article also references the work of Hans Freudenthal and Lancelot Hogben regarding cosmic languages. Finally, the author addresses the potential risks of contact, citing Professor Iosif Shklovsky's warnings about the 'profound crises' that might face a developing civilization, such as thermonuclear catastrophe or the creation of artificial intelligence. The author concludes by advising that humanity must remain level-headed and prepared for the unprecedented challenges that contact with a superior civilization would bring.