Monte Carlo estimation of the probability of causal contacts between communicating civilizations

Lares, M.; Funes, J. G.; Gramajo, Luciana

doi:10.1017/s147355042000018x

Cited by 5 publications

(3 citation statements)

References 75 publications

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“…where θ is the unit step function, r o is the vector position of the Earth, and L dL L L L ò r = ¯( ) is the average longevity of the emission processes, a key factor in determining the probability of contact (Lares et al 2020;Kipping et al 2020;Balbi & Ćirković 2021).…”

Section: The Modelmentioning

confidence: 99%

Inferring the Rate of Technosignatures from 60 yr of Nondetection

Grimaldi

2023

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For about the last 60 yr the search for extraterrestrial intelligence has been monitoring the sky for evidence of remotely detectable technological life beyond Earth, with no positive results to date. While the lack of detection can be attributed to the highly incomplete sampling of the search space, technological emissions may be actually rare enough that we are living in a time when none cross the Earth. Here we explore the latter possibility and derive the likelihood of the Earth not being crossed by signals for at least the last 60 yr to infer upper bounds on their rate of emission. Under the assumption that technological emitters are distributed uniformly in the Milky Way and that they generate technoemissions at a constant rate, we find less than about one to five emissions generated per century with 95% credible level. This implies optimistic waiting times until the next crossing event of no less than 60–1800 yr with a 50% probability. A significant fraction of highly directional signals increases the emission rates’ upper bounds, but without systematically changing the waiting time. Although these probabilistic bounds are derived from a specific model and their validity depends on the model’s assumptions, they are nevertheless quite robust against weak time dependences of the emission rate or nonuniform spatial distributions of the emitters. Our results provide therefore a benchmark for assessing the lack of detection and may serve as a basis to form optimal strategies for the search for extraterrestrial intelligence.

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Section: The Modelmentioning

confidence: 99%

Inferring the Rate of Technosignatures from 60 yr of Nondetection

Grimaldi

2023

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“…Prantzos (2020) and Lares et al (2020) both performed Monte Carlo simulations of the rise and fall of technological life in the galaxy, exploring the likelihood of contact via communication given various assumptions. Prantzos emphasized the importance of the L term in the Drake Equation, and Lares et al emphasized that contact is most likely to occur just after the discovery of the relevant communicative technology.…”

Section: The Drake Equation and The Fermi Paradoxmentioning

confidence: 99%

SETI in 2020

Wright

2021

Preprint

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In the spirit of Trimble's "Astrophysics in XXXX" series, I very briefly and subjectively review developments in SETI in 2020. My primary focus is 74 papers and books published or made public in 2020, which I sort into six broad categories: results from actual searches, new search methods and instrumentation, target and frequency seleciton, the development of technosignatures, theory of ETIs, and social aspects of SETI.

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“…To properly address the temporal dependences implicit in the estimate of N , a more flexible approach can be adopted, as proposed in Balbi (2018a) (see also Grimaldi 2017;Lares et al 2020;Grimaldi 2020). This relies on noticing that any technosignature that we can observe must be located within our past light cone; that is, we can detect a technosignature at distance R from Earth, at present, if and only if:…”

Section: A More General Approachmentioning

confidence: 99%

Longevity is the key factor in the search for technosignatures

Balbi,

Ćirković

2021

Preprint

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It is well-known that the chances of success of SETI depend on the longevity of technological civilizations or, more broadly, on the duration of the signs of their existence, or technosignatures. Here, we re-examine this general tenet in more detail, and we show that its broader implications were not given the proper significance. In particular, an often overlooked aspect is that the duration of a technosignature is in principle almost entirely separable from the age of the civilization that produces it. We propose a classification scheme of technosignatures based on their duration and, using Monte Carlo simulations, we show that, given an initial generic distribution of Galactic technosignatures, only the ones with the longest duration are likely to be detected. This tells us, among other things, that looking for a large number of shortlived technosignatures is a weaker observational strategy than focusing the search on a few long-lived ones. It also suggests to abandon any anthropocentric bias in approaching the question of extraterrestrial intelligence. We finally give some ideas of possible pathways that can lead to the establishment of long-lived technosignatures.

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Monte Carlo estimation of the probability of causal contacts between communicating civilizations

Cited by 5 publications

References 75 publications

Inferring the Rate of Technosignatures from 60 yr of Nondetection

Inferring the Rate of Technosignatures from 60 yr of Nondetection

SETI in 2020

Longevity is the key factor in the search for technosignatures

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