SETI & Technosignatures

Technosignatures Longevity And Lindy’s Law

By Keith Cowing
Status Report
May 2, 2024
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Technosignatures Longevity And Lindy’s Law
PDF of technoemission longevity L (top row) and starting time t of emissions (bottom row) calculated under the assumption that the unconditional PDF of t is uniform over the interval [1, 1010] yr. Panels (a)-(c) show the conditional, Eq. (9) and unconditional, Eq. (8), PDFs of L for three values of the exponent α, whereas panel (d) shows the corresponding values of L such that L ≤ L with 95 % probability. Panels (e) and (f) show the PDF of t calculated numerically for different values of α and (e) for Ro large enough to encompass the entire galaxy and (f) for Ro = 100 ly. Panel (g) shows the values of t such that t ≤ t with 95 % probability calculated for different values of Ro. — physics.pop-ph

The probability of detecting technosignatures (i.e. evidence of technological activity beyond Earth) increases with their longevity, or the time interval over which they manifest.

Therefore, the assumed distribution of longevities has some bearing on the chances of success of technosignature searches, as well as on the inferred age of technosignatures following a first contact.

Here, we investigate the possibility that the longevity of technosignatures conforms to the so-called Lindy’s law, whereby, at any time, their remaining life expectancy is roughly proportional to their age. We show that, if Lindy’s law applies, the general tenet that the first detected technosignature ought to be very long lived may be overruled.

We conclude by discussing the number of emitters that had to appear, over the history of the Galaxy, in order for one of them to be detectable today from Earth.

A. Balbi, C. Grimaldi

Comments: 9 pages, 4 figures
Subjects: Popular Physics (physics.pop-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2405.00020 [physics.pop-ph] (or arXiv:2405.00020v1 [physics.pop-ph] for this version)
Journal reference: The Astronomical Journal, 167, 119 (2024)
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Submission history
From: Claudio Grimaldi
[v1] Tue, 20 Feb 2024 22:19:01 UTC (133 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) 🖖🏻