Physics and Astronomy Special Event
October 20, 1999
Fred Adams visit


Dr. Fred Adams is an associate professor of physics at the University of Michigan, has received ample recognition as an astrophysicist (including the Robert J. Trumpler Award and the Helen B. Warner Prize), and has recently coauthored a book on the physics of the distant future, The Five Ages of the Universe. On October 20, as part of the Calvin Science Division's weeklong dedication of the new DeVries Hall of Science, Dr. Adams will present both a departmental colloquium and a public lecture.

Colloquium Abstract

This talk outlines astrophysical issues related to the long term fate of the universe. We consider the evolution of planets, stars, stellar populations, galaxies, and the universe itself over time scales which greatly exceed the current age of the universe. This discussion starts with new stellar evolution calculations which follow the future evolution of the low mass (M type) stars that dominate the stellar initial mass function. We then determine the final mass distribution of stellar remnants -- the neutron stars, white dwarfs, and brown dwarfs remaining at the end of stellar evolution. After 1-10 trillion years, the supply of interstellar gas becomes exhausted, yet star formation continues at a highly attenuated level through brown dwarf collisions. This process tails off as the galaxy gradually depletes its stars by ejecting the majority, and driving a minority toward accretion onto massive black holes. As the galaxy disperses, weakly interacting dark matter particles are accreted by white dwarfs, where they subsequently annihilate with each other and thereby keep the old stellar remnants relatively "warm". After accounting for the destruction of the galaxy, we consider the fate of the expelled degenerate objects (planets, white dwarfs, and neutron stars) within the assumption that proton decay is a viable process. The evolution and eventual sublimation of these objects is dictated by the decay of their constituent nucleons, and this evolutionary scenario is developed in some detail. After white dwarfs and neutron stars have disappeared, galactic black holes slowly lose their mass as they emit Hawking radiation. After the largest black holes have evaporated, the universe slowly slides into darkness.

Public Lecture Abstract

Current astronomical data strongly suggest that the universe will continue its expansion forever and we can now describe the life story of our universe in unprecedented detail. In the first stage of its development, the Primordial Era, the universe burst into existence at the Big Bang, forged nuclei of the light elements, and expanded to the present day. We now live in the midst of the second, Stelliferous Era, dominated by the life giving energy of stars. After the stars burn out trillions of years from now, the galaxy and the universe enter the Degenerate Era. In this future epoch, dead stellar remnants collect dark matter, galaxies evaporate, and protons eventually decay away. With little else remaining, black holes inherit the universe during the next Black Hole Era. But even black holes cannot live forever, and they slowly evaporate by emitting Hawking radiation through a tortuously slow quantum mechanical process. After the largest black holes are gone, the universe slowly shuffles into its final Dark Era.

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