A birth-death-migration model for life in astrophysical environments

Lingam, Manasvi; Grimaldi, Claudio; Balbi, A.

doi:10.1093/mnras/stab3108

Cited by 7 publications

(2 citation statements)

References 72 publications

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“…We caution, however, that our analysis does not rule out the prospects for surficial life altogether owing to the uncertainties and caveats involved, some of which were encountered previously and others are delineated hereafter. Furthermore, the AGN phase is primarily operational over the Salpeter timescale, due to which life might be able to emerge and diversify on the surface -perhaps by migrating from the subsur-face or from other worlds (Chen et al 2018;Ginsburg et al 2018;Lingam et al 2022) -once this phase has ceased.…”

Section: Discussionmentioning

confidence: 99%

The impact of AGN outflows on the surface habitability of terrestrial planets in the Milky Way

Ambrifi,

Balbi,

Lingam

et al. 2022

Preprint

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It is well-known that active galactic nuclei (AGN) are accompanied by winds and outflows, some of which may reach weakly relativistic speeds of about 10 percent the speed of light. Yet, in spite of their ubiquity, the impact of AGN outflows in modulating surface habitability of terrestrial planets on galactic scales, using the Milky Way as the basis for comparison, is poorly investigated and inadequately understood. In this work, we address this issue by focusing on two key mechanisms: AGN winds can heat atmospheres and drive atmospheric escape, as well as stimulate the formation of nitrogen oxides and thence cause ozone depletion. By developing simple models, we estimate the maximal distance up to which these deleterious effects are rendered significant for Earth-like planets in the Milky Way, and thereby demonstrate that this value may extend to 1 kpc. In the case of quasars hosting larger supermassive black holes, such effects could actually influence the AGN host galaxy as a whole.

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Section: Discussionmentioning

confidence: 99%

The impact of AGN outflows on the surface habitability of terrestrial planets in the Milky Way

Ambrifi,

Balbi,

Lingam

et al. 2022

Preprint

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“…If the question is posed purely in terms of nontechnological life, then the answer would appear to be "no", unless interstellar transport of life is highly effective (e.g. Crick & Orgel 1973;Napier 2004;Grimaldi et al 2021;Lingam et al 2022). In addition, however, N (bio) should include biosignatures stemming from biospheres that have been purposely engineered for habitation, for example, planets which have been "terraformed".…”

Section: Abundancementioning

confidence: 99%

The Case for Technosignatures: Why They May Be Abundant, Long-lived, Highly Detectable, and Unambiguous

Wright,

Haqq-Misra,

Frank

et al. 2022

Preprint

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The intuition suggested by the Drake Equation implies that technology should be less prevalent than biology in the galaxy. However, it has been appreciated for decades in the SETI community that technosignatures could be more abundant, longer-lived, more detectable, and less ambiguous than biosignatures.We collect the arguments for and against technosignatures' ubiquity, and discuss the implications of some properties of technological life that fundamentally differ from non-technological life, in the context of modern astrobiology: it can spread among the stars to many sites, it can be more easily detected at large distances, and it can produce signs that are unambiguously technological.As an illustration in terms of the Drake Equation, we consider two Drake-like equations, for technosignatures (calculating N (tech)) and biosignatures (calculating N (bio)). We argue that Earth and humanity may be poor guides to the longevity term L, and that its maximum value could be very large, in that technology can outlive its creators and even its host star. We conclude that while the Drake equation implies that N (bio) N (tech), it is also plausible that N (tech) N (bio). As a consequence, as we seek possible indicators of extraterrestrial life, for instance via characterization of the atmospheres of habitable exoplanets, we should search for both biosignatures and technosignatures. This exercise also illustrates ways in which biosignature and technosignature searches can complement and supplement each other, and how methods of technosignature search, including old ideas from SETI, can inform the search for biosignatures and life generally.

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