Broadband SETI: A New Strategy To Find Nearby Alien Civilizations

One of the most interesting questions that astronomy can hope to answer is: are we alone in our Milky Way galaxy?

A detection of an electromagnetic (EM) signal generated by an extraterrestrial technological intelligence (ETI), or the presence in our solar system of an alien probe, would answer this question in the affirmative. Purposeful interstellar communication is a 2-way street – the transmitting and receiving technological intelligence (TI) both need to do its part.

As the receiving TI, our EM search programs should incorporate a model of what a transmitting TI is likely to be doing. Published searches for extraterrestrial technological intelligence (SETI) have generally not done so and, thus, have often been sub-optimally designed. We propose an improved search technique that more closely corresponds to astronomical surveys that have been undertaken for reasons that have nothing to do with SETI.

Published non-SETI radio and optical surveys are sufficiently extensive that they already supply meaningful constraints on the prevalence of nearby purposely communicative alien civilizations. Purposeful communication can also include the sending of spaceships (probes). The absence of evidence for alien probes in the solar system suggests that no alien civilization has passed within 100 light-years of Earth during the past few billion years.

B. Zuckerman

Comments: Accepted for publication in ApJ but not yet set in stone
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Popular Physics (physics.pop-ph)
Cite as: arXiv:2603.07333 [astro-ph.IM] (or arXiv:2603.07333v1 [astro-ph.IM] for this version)
https://doi.org/10.48550/arXiv.2603.07333
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Submission history
From: Benjamin Zuckerman
[v1] Sat, 7 Mar 2026 20:41:04 UTC (113 KB)
https://arxiv.org/abs/2603.07333
Astrobiology