Risa Wechsler is the Director of the Kavli Institute for Particle Astrophysics and Cosmology and an Professor of Physics at Stanford and the SLAC National Accelerator Laboratory. Her work explores questions about our existence on the largest scales. She is currently playing a leading role in mapping out tens of billions of galaxies over the last 13 billion years using large sky surveys. Her research uses these surveys combined with large numerical simulations of the universe to learn how galaxies form and to understand the nature of dark matter and dark energy. Wechsler is a Fellow of the American Physical Society as well as a former NASA Hubble Fellow, and has written about and discussed science in numerous public venues including TED, Teen Vogue, and the BBC.