Science Café Fort Collins — September 10, 2008

Location	Starry Night Espresso Cafe 112 South South College Street
Led by	Dr. Gavin Polhemus, Physics Instructor, Poudre School District
Topic:	The New Story of Our Universe

Over the past ten years new observations have revealed surprising details about how we got here, what is out there, and where it is all going.

For much of the last century we have known the basic story of our universe—It began in a fiery explosion about 10 to 20 billion years ago and has been expanding and cooling ever since. Recent observations by the Hubble Space Telescope, the Wilkinson Microwave Anisotropy Probe and others have added amazing detail to this story, revealing how tiny variations in the density of the early universe seeded the formation of stars, galaxies, and the large scale structure that we see around us today. New players—dark matter and dark energy—have joined the cosmic cast. These dark ingredients are far more abundant that ordinary matter and dominate the story line of our universe. We now know that our universe is 13.7 billion years old and its expansion is accelerating without an end, headed toward a cold, dark, empty expanse. We have also seen tantalizing clues about the earliest moments of the Big Bang, revealing a possible mechanism for the creation of the energy and mass of which we are made.

We are living in the golden age of cosmology. Join in the discovery as Dr. Polhemus shows how science is answering some of the greatest questions of all time.

Meet Dr. Gavin Polhemus

Gavin Polhemus’ research has focused on black holes and string theory. He began studying string theory as an undergraduate at Stanford University, and went on to earn a Ph.D. in Physics from the University of Chicago in 1999. His early research addressed quantum mechanical aspects of black holes in string theory. These models used properties of D-branes, extended objects in string theory, to predict the thermodynamic properties of black holes in higher dimensions. He also studied spin effects in particle scattering in an eleven dimensional extension of string theory called matrix-theory. His most recent work has been done as a member of the JILA institute at the University of Colorado. In collaboration with Colin Wallace and Prof. Andrew Hamilton, he has been examining the implications of heating processes deep inside ultra-massive black holes like the one at the center of our galaxy. These processes produce so much entropy that they strain our current understanding of how information about what happens inside a black hole is encoded in the outgoing Hawking radiation produced when the black hole decays.

Dr. Polhemus lives in Fort Collins and teaches advanced physics courses at Poudre High School.