**Noam Soker (Technion) |** Astrophysical Naturalness |

Abstract:

I suggest that stars introduce mass and density scales that lead to `naturalness’ in the Universe. Namely, two ratios of order unity. The first ratio of order one involves the Planck mass, the mass of the proton, and the mass of stars. The second ratio of order one involves the Planck density and the dynamical density that one derives from the nuclear lifetime of stars. 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.

When: December 29, 2021 02:00 PM (Israel Standard Time).

__Where:__ Room 223, Multipurpose Building and over Zoom