[astro-ph.IM] The search for extraterrestrial intelligence (SETI) has traditionally framed the detection challenge with a focus on the parameter L in the Drake equation – the communicative lifetime of a civilisation.
I argue that the more pertinent quantity is τd, the duration during which a civilisation produces technosignatures that are actually detectable by us, now. Modelling technological progress as an exponential process, we show that τd=α−1ln(Kmax/Kmin), where α is the rate of technological acceleration and [Kmin,Kmax] brackets the technology levels accessible to our instruments.
As α increases, τd can shrink to mere decades, dramatically narrowing the window in which civilisations overlap technically. This “technology mismatch” has implications for future search strategies, emphasising broadband and technology-agnostic approaches, as well as anomaly detection across multi-wavelength/messenger survey data.
Michael A. Garrett
Comments: 4 pages, In Advancing the Search for Technosignatures, Proceedings of IAU Symposium #404 (forthcoming)
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2607.07413 [astro-ph.IM](or arXiv:2607.07413v1 [astro-ph.IM] for this version)
https://doi.org/10.48550/arXiv.2607.07413
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Submission history
From: Mike Garrett
[v1] Wed, 8 Jul 2026 13:44:57 UTC (37 KB)
https://arxiv.org/abs/2607.07413
Astrobiology, SETI,
