Multiverse Predictions for Habitability: The Number of Stars and their Properties

TL;DR

This paper explores how different habitability criteria in a multiverse context influence the likelihood of life-supporting universes and proposes testable predictions based on these criteria, potentially falsifying the multiverse hypothesis.

Contribution

It systematically examines various habitability factors and their impact on multiverse expectations, linking fundamental constants to life-supporting conditions.

Findings

Habitability criteria significantly affect multiverse predictions.

Certain conditions like photosynthesis and tidal locking influence life's emergence.

Predictions can be tested with future astronomical observations.

Abstract

In a multiverse setting, we expect to be situated in a universe that is exceptionally good at producing life. Though the conditions for what life needs to arise and thrive are currently unknown, many will be tested in the coming decades. Here we investigate several different habitability criteria, and their influence on multiverse expectations: Does complex life need photosynthesis? Is there a minimum timescale necessary for development? Can life arise on tidally locked planets? Are convective stars habitable? Variously adopting different stances on each of these criteria can alter whether our observed values of the fine structure constant, the electron to proton mass ratio, and the strength of gravity are typical to high significance. This serves as a way of generating predictions for the requirements of life that can be tested with future observations, any of which could falsify the multiverse scenario.