Understanding The Universe – With Guest Dr. Katherine Freese (Part 1)
John P. Millis, PhD for redOrbit.com – Your Universe Online
What do we really know about the Universe? A century ago, astronomers would have said that we lived in a static Universe, and all of the visible matter was contained in a galaxy we call the Milky Way. Those fuzzy spiral “nebulae” out there? Strange to be sure, but they are contained within our little corner of the cosmos.
Of course, an astronomer named Edwin Hubble, the namesake for the famed NASA telescope, changed all that. He calculated that some of those fizzy spiral nebulae were not nebulae at all, but rather whole other galaxies. Not only that, but they were all running away from us in an ever expanding Universe that was much larger than anyone had ever imagined.
This changed everything. Over the last century we have continued to be surprised by what we find in the cosmos, with ever-stranger wrinkles that challenge us to re-think our physical picture of the Universe.
To explore how we arrived at this point – what we know, or don’t yet know, about the Universe – I am joined by Dr. Katherine Freese, a professor of theoretical physics from the University of Michigan, and an expert in the field of cosmology. In this first episode of the three part series, we will take a look at how our understanding has changed over the last hundred years, and what we think might be on the horizon.
Dr. Freese is the George E. Uhlenbeck Professor of Physics at the University of Michigan, and the Associate Director of the Michigan Center for Theoretical Physics. She works on a wide range of topics in theoretical cosmology and astroparticle physics. She has been working to identify the dark matter and dark energy that permeate the universe as well as to build a successful model for the early universe immediately after the Big Bang. She has shown that most of the mass in galaxies does not consist of ordinary stellar material, and has proposed ways to look for alternatives such as supersymmetric particles. Currently there is a great deal of excitement about possible detections of these particles. Recently she has proposed Dark Stars as the first stars to form in the Universe.
Professor Freese has also been working on inflation, an early expansion phase which led to our inhabitable universe. Her Natural Inflation model is the theoretically best-motivated variant of inflation; it uses axionic particles to provide the required flat potentials to drive the expansion. In 2013, observations made by the European Space Agency’s Planck Satellite show that the framework of natural inflation matches the data. Freese also studies cosmology of extra dimensions, in which our three-dimensional universe is embedded in higher dimensions.