Broadcasting but not receiving: density dependence considerations for SETI signals

Smith, Richard

doi:10.1017/s1473550409990097

Cited by 11 publications

(14 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While data suggest that a significant fraction of Sun-like stars may host Earth-sized planets within the habitable zone 1 , the chances of detecting hypothetical extraterrestrial signals still remain highly speculative. Estimates of the detection probability 2 3 4 often rely on arguments, such as the Drake equation 5 , aimed at determining the odds that communicating civilizations exist in the Milky Way. Yet, given the lack of empirical data, it is highly uncertain that even microbiological life exists elsewhere than the Earth 6 , let alone complex, intelligent life.…”

mentioning

confidence: 99%

Signal coverage approach to the detection probability of hypothetical extraterrestrial emitters in the Milky Way

Grimaldi

2017

Sci Rep

View full text Add to dashboard Cite

The lack of evidence for the existence of extraterrestrial life, even the simplest forms of animal life, makes it is difficult to decide whether the search for extraterrestrial intelligence (SETI) is more a high-risk, high-payoff endeavor than a futile attempt. Here we insist that even if extraterrestrial civilizations do exist and communicate, the likelihood of detecting their signals crucially depends on whether the Earth lies within a region of the galaxy covered by such signals. By considering possible populations of independent emitters in the galaxy, we build a statistical model of the domain covered by hypothetical extraterrestrial signals to derive the detection probability that the Earth is within such a domain. We show that for general distributions of the signal longevity and directionality, the mean number of detectable emitters is less than one even for detection probabilities as large as 50%, regardless of the number of emitters in the galaxy.

show abstract

mentioning

confidence: 99%

Signal coverage approach to the detection probability of hypothetical extraterrestrial emitters in the Milky Way

Grimaldi

2017

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Following the end of the civilization, there is still a region which is filled with the emitted signals. This approach has been also considered in other statistical models (e.g., Smith 2009;Grimaldi 2017;Grimaldi et al 2018). The trailing front, or surface of last contact (SLC) also grows from the arepresents the region R in space and time which is causally connected to the emitter (E, left vertex), following an 'A' type event ('Awakening') in which the node acquires the communication capability.…”

Section: Methods and Working Hypothesesmentioning

confidence: 99%

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

Lares

Funes

Gramajo

2020

International Journal of Astrobiology

View full text Add to dashboard Cite

In this work we address the problem of estimating the probabilities of causal contacts between civilizations in the Galaxy. We make no assumptions regarding the origin and evolution of intelligent life. We simply assume a network of causally connected nodes. These nodes refer somehow to intelligent agents with the capacity of receiving and emitting electromagnetic signals. Here we present a three-parametric statistical Monte Carlo model of the network in a simplified sketch of the Galaxy. Our goal, using Monte Carlo simulations, is to explore the parameter space and analyse the probabilities of causal contacts. We find that the odds to make a contact over decades of monitoring are low for most models, except for those of a galaxy densely populated with long-standing civilizations. We also find that the probability of causal contacts increases with the lifetime of civilizations more significantly than with the number of active civilizations. We show that the maximum probability of making a contact occurs when a civilization discovers the required communication technology.

show abstract

“…Though it has existed in different forms throughout time in different fields being applied to more narrow problems, its most general and widely used form was first proposed, without proof, by Philip Morse 17 in 1958 and given a rigorous proof by John Little 18 in 1961. Little's Law relates the average number of items in a queue, (bank queue line customers, cars at a toll booth, even Drake's equation for the estimated number of intelligent species 19 ) to the average arrival rate at the queue, , and the average wait time in the queue, :…”

Section: Active Monetary Base In Bitcoin Analyzed By Little's Lawmentioning

confidence: 99%

Bitcoin Average Dormancy: A Measure of Turnover and Trading Activity

Smith¹

2018

ledger

Self Cite

View full text Add to dashboard Cite

Attempts to accurately measure the monetary velocity or related properties of Bitcoin have often attempted to either directly apply definitions from traditional macroeconomic theory or to use specialized metrics relative to the properties of the Blockchain such as bitcoin-days destroyed. In this paper, it is demonstrated that beyond being a useful metric, bitcoin-days destroyed has mathematical properties that allow one to calculate the average dormancy (time since last use in a transaction) of the bitcoins used in transactions over a given time period. In addition, transaction volume and average dormancy are shown to have unexpected significance in helping estimate the average size of the pool of traded bitcoins by virtue of the expression Little's Law, though only under limited conditions.

show abstract

Broadcasting but not receiving: density dependence considerations for SETI signals

Cited by 11 publications

References 7 publications

Signal coverage approach to the detection probability of hypothetical extraterrestrial emitters in the Milky Way

Signal coverage approach to the detection probability of hypothetical extraterrestrial emitters in the Milky Way

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

Bitcoin Average Dormancy: A Measure of Turnover and Trading Activity

Contact Info

Product

Resources

About