
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.
Earth and Planetary Astrophysics (astro-ph.EP), Cosmology and Nongalactic Astrophysics (astro-ph.CO), Elementary particle physics, FOS: Physical sciences, QC793-793.5, multiverse, habitability, multiverse; habitability; planetary characteristics, 510103 - Cosmology and extragalactic astronomy, planetary characteristics, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Earth and Planetary Astrophysics (astro-ph.EP), Cosmology and Nongalactic Astrophysics (astro-ph.CO), Elementary particle physics, FOS: Physical sciences, QC793-793.5, multiverse, habitability, multiverse; habitability; planetary characteristics, 510103 - Cosmology and extragalactic astronomy, planetary characteristics, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 4 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Top 10% | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Average | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
