SETI & Technosignatures

Limits of Detecting Extraterrestrial Civilizations

By Keith Cowing
July 21, 2021
Filed under
Limits of Detecting Extraterrestrial Civilizations
Galaxy M51 is a spiral galaxy, about 30 million light years away, that is in the process of merging with a smaller galaxy seen to its upper left. CREDIT Image credit: X-ray: NASA/CXC/SAO; Optical: Detlef Hartmann; Infrared: Courtesy NASA/JPL-Caltech.

The search for extraterrestrial intelligence (SETI) is a scientific endeavor which struggles with unique issues — a strong indeterminacy in what data to look for and when to do so.

This has led to attempts at finding both fundamental limits of the communication between extraterrestrial intelligence and human civilizations, as well as benchmarks so as to predict what kinds of signals we might most expect. Previous work has been formulated in terms of the information-theoretic task of communication, but we instead argue it should be viewed as a detection problem, specifically one-shot (asymmetric) hypothesis testing. With this new interpretation, we develop fundamental limits as well as provide simple examples of how to use this framework to analyze and benchmark different possible signals from extraterrestrial civilizations.

We show that electromagnetic signaling for detection requires much less power than for communication, that detection as a function of power can be non-linear, and that much of the analysis in this framework may be addressed using computationally efficient optimization problems, thereby demonstrating tools for further inquiry.

Ian George, Xinan Chen, Lav R. Varshney

Comments: Main Text: 16 pages, 1 Figure. Comments welcome
Subjects: Information Theory (cs.IT); Instrumentation and Methods for Astrophysics (astro-ph.IM); Popular Physics (physics.pop-ph)
Cite as: arXiv:2107.09794 [cs.IT] (or arXiv:2107.09794v1 [cs.IT] for this version)
Submission history
From: Ian George
[v1] Tue, 20 Jul 2021 22:53:00 UTC (560 KB)
Astrobiology, SETI,

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻