Habitable Zones & Global Climate

Multiverse Predictions for Habitability: Planetary Characteristics

By Keith Cowing
Status Report
February 27, 2023
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Multiverse Predictions for Habitability: Planetary Characteristics
Ratio of frequencies for a sample of 105 points. The color denotes the number of observers for a given parameter choice (relative to our values). The dashed line denotes the region of stable obliquities. The cross marks the values of the Earth-Moon system. — astro-ph.EP

Recent detections of potentially habitable exoplanets around sunlike stars demand increased exploration of the physical conditions that can sustain life, by whatever methods available.

Insight into these conditions can be gained by considering the multiverse hypothesis; in a multiverse setting, the probability of living in our universe depends on assumptions made about the factors affecting habitability. Various proposed habitability criteria can be systematically considered to rate each on the basis of their compatibility with the multiverse, generating predictions which can both guide expectations for life’s occurrence and test the multiverse hypothesis.

Here, we evaluate several aspects of planetary habitability, and show that the multiverse does indeed induce strong preferences among them. We find that the notion that a large moon is necessary for habitability is untenable in the multiverse scenario, as in the majority of parameter space, moons are not necessary to maintain stable obliquity.

Further, we consider various proposed mechanisms for water delivery to the early Earth, including delivery from asteroids, both during giant planet formation and a grand tack, delivery from comets, and oxidation of a primary atmosphere by a magma ocean. We find that, depending on assumptions for how habitability depends on water content, some of these proposed mechanisms are disfavored in the multiverse scenario by Bayes factors of up to several hundred.

McCullen Sandora, Vladimir Airapetian, Luke Barnes, Geraint F. Lewis

Comments: 26 pages, 3 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Cite as: arXiv:2302.12376 [astro-ph.EP] (or arXiv:2302.12376v1 [astro-ph.EP] for this version)
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Journal reference: Universe 2023, 9, 2
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Submission history
From: McCullen Sandora
[v1] Fri, 24 Feb 2023 00:46:17 UTC (1,416 KB)

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) 🖖🏻