Image of The Cosmic Cocktail book cover

Public Lecture: The Dark Side of the Universe

Katherine Freese, Jeff and Gail Kodosky Endowed Chair in Physics, The University of Texas at Austin

The ordinary atoms that make up the known universe, from our bodies and the air we breathe to the planets and stars, constitute only 5% of all matter and energy in the Cosmos. The remaining 95% is made up of a recipe of 25% dark matter and 70% dark energy, both nonluminous components whose nature remains a mystery. This talk will start with the evidence for the existence of the ‘dark side’ of the Universe and describe the hunt to understand its nature. The bulk of the mass in the Universe is thought to consist of a new kind of particle, such as Weakly Interacting Massive Particles (WIMPs) or axions. Billions of them pass through our bodies every second without our even realizing it, yet their gravitational pull is capable of whirling stars and gas at breakneck speeds around the centers of galaxies, and bending light from distant bright objects. This talk presents various approaches in searching for these particles: in underground laboratories, satellites in space, the particle accelerator at CERN in Geneva, tracks in ancient rocks, and even DNA. The presentation also addresses Dark Stars, the idea for powering early stars with dark matter heating instead of fusion, and concludes with the question of the Dark Energy that is driving accelerated expansion of the Cosmos today.

This lecture provides an overview of the cosmic cocktail that makes up our Universe.