Astrophysical Naturalness

TL;DR

The paper proposes that stars establish mass and density scales resulting in natural ratios in the universe, offering an astrophysical perspective on naturalness that differs from fundamental particle domain explanations.

Contribution

It introduces the concept of astrophysical naturalness, showing how stellar scales create natural ratios among fundamental quantities, providing an alternative to particle physics explanations.

Findings

Two ratios of order unity involving stellar and fundamental scales.

Density ratio between dark energy and stellar dynamical timescales.

Large but significantly smaller range of naturalness compared to Planck density.

Abstract

I suggest that stars introduce mass and density scales that lead to `naturalness' in the Universe. Namely, two ratios of order unity. (1) The combination of the stellar mass scale, M*, with the Planck mass, MPl, and the Chandrasekhar mass leads to a ratio of order unity that reads NPl*=MPl/[(M*)(mp)^2]^{1/3}=0.15-3, where mp is the proton mass. (2) A system with a dynamical time equals to the nuclear life times of stars, tau, has a density of rhoD = 1/[(G)(tau)^2]. The ratio of the dark energy density to this density is NL*=rhoL/rhoD=10^{-7} - 10^{5}$. Although the range is large, it is critically much smaller than the 123 orders of magnitude usually referred to when rhoL is compered to the Planck density. In the pure fundamental particles domain there is no naturalness; either naturalness does not exist or there is a need for a new physics or new particles. The `Astrophysical Naturalness' offers a third possibility: stars introduce the combinations of, or relations among, known fundamental quantities that lead to naturalness.