Scientific Colloquium
April 8, 2020, 3:30 p.m.
Building 3, Goett Auditorium

"The Degree of Fine-Tuning in our Universe" 


The fundamental constants of nature must fall within a range of values in order for the universe to develop structure and ultimately support life. This talk considers current constraints on these quantities and assesses the degree of tuning required for the universe to be viable. In the realm of particle physics, the relevant parameters are the strengths of the fundamental forces and the particle masses. Additional astrophysical parameters include the cosmic energy density, the cosmological constant, the abundances of ordinary matter and dark matter, and the amplitude of primordial density fluctuations. These quantities are constrained by the necessity that the universe lives for a long time, emerges from its early epochs with an acceptable chemical composition, and successfully produces galaxies. On smaller scales, stars and planets must be able to form and function. The stars must have sufficiently long lifetimes and hot surface temperatures. We also consider potential fine-tuning related to the triple alpha reaction that produces carbon, the case of unstable deuterium, and the possibility of stable diprotons. For all of these issues, the goal is to delineate the range of parameter space for which universes can remain habitable. In spite of its biophilic properties, our universe is not optimized for the emergence of life, in that the proper variations could result in more galaxies, stars, and potentially habitable planets.

About the Speaker:

Born in Redwood City, California, Fred Adams received his undergraduate training in Mathematics and Physics from Iowa State University in 1983 and his PhD in Physics from the University of California (Berkeley) in 1988. After a postdoctoral fellowship at the Harvard-Smithsonian Center for Astrophysics, he joined the Physics Faculty at the University of Michigan in 1991. He was promoted to Full Professor in 2001, elected to the Michigan Society of Fellows in 2007, and named as the Ta-you Wu Collegiate Professor of Physics in 2014. He has received the Robert J. Trumpler Award from the ASP, the NSF Young Investigator Award, the Helen B. Warner Prize from the AAS, and is a fellow of the American Physical Society. Professor Adams works in theoretical astrophysics with a focus on the study of exoplanets, star formation, and cosmology. He is internationally recognized for his work on the radiative signature of the star formation process, the dynamics of circumstellar disks, the development of a theory for the initial mass function, and studies of extra-solar planetary systems. In cosmology, he has studied the inflationary universe, cosmological phase transitions, magnetic monopoles, and cosmic background radiation fields. His work in cosmology also includes explorations of the long-term fate and evolution of the universe, as well as fine-tuning issues.
                   
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