The Cosmic Ecosystem: Connecting the Life Cycles of Stars, Galaxies, and the Universe

Dr. Robert Kennicutt Jr.

Eminent Scholar Lecture

The past decade has seen a quiet revolution in our understanding of the “Origins” questions in astronomy, namely how galaxies, stars, planets, the chemical elements, and the universe itself were formed and evolve over the history of time.  Observations of galaxies with the Hubble Space Telescope and a variety of ground-based instruments have allowed us to reconstruct an empirical history of galaxies from the Big Bang to the present, and the introduction of sophisticated numerical models have transformed our theoretical understanding this evolution. Remarkably, the same theory for the evolution and structure of our universe, in which dark matter and dark energy play the dominant roles, when extrapolated to smaller scales also reproduces most of the observed properties of galaxies over cosmic time.  In this picture the key physical processes take place over an enormous dynamic range of physical scales, from cosmological scales to those of individual massive stars and black holes, all closely linked and interacting in a what can be regarded as a self-regulating ecosystem. This talk will describe how the observational, theoretical, and numerical pieces of this new picture came together, and will highlight some of the current questions, challenges, and exciting opportunities which lie ahead.