Katherine J. Mack (born 1 May 1981) is a theoretical cosmologist who holds the Hawking Chair in Cosmology and Science Communication at Perimeter Institute. Her academic research investigates dark matter, vacuum decay and the epoch of reionisation. Mack is also a popular science communicator who participates in social media and regularly writes for Scientific American, Slate, Sky & Telescope, Time and Cosmos. Early life and education Mack became interested in science as a child and built solar-powered cars out of Lego blocks. Her mother is a fan of science fiction, and encouraged Mack to watch Star Trek and Star Wars. Her grandfather was a student at Caltech and worked on the Apollo 11 mission. She became more interested in spacetime and the Big Bang after attending talks by scientists such as Stephen Hawking. Mack attended California Institute of Technology, and appeared as an extra in the opening credits of the 2001 American comedy film Legally Blonde when they filmed on campus. She received her undergraduate degree in physics in 2003. Mack obtained her PhD in astrophysics from Princeton University in 2009. Her thesis on the early universe was supervised by Paul Steinhardt. Research and career After earning her doctorate, Mack joined the University of Cambridge as a Science and Technology Facilities Council (STFC) postdoctoral research fellow at the Kavli Institute for Cosmology. Later in 2012, Mack was a Discovery Early Career Researcher Award (DECRA) Fellow at the University of Melbourne. Mack was involved with the construction of the dark matter detector SABRE. In January 2018, Mack became an Assistant Professor and a member of university's Leadership in Public Science Cluster in the Department of Physics at North Carolina State University. She joined the Perimeter Institute for Theoretical Physics in June 2022, as the inaugural Hawking Chair in Cosmology and Science Communication. The Canadian multidisciplinary research organization CIFAR named her one of the CIFAR Azrieli Global Scholars in 2022. Mack works at the intersection between fundamental physics and astrophysics. Her research considers dark matter, vacuum decay, the formation of galaxies, observable tracers of cosmic evolution and the Epoch of Reionisation. Mack has described dark matter as one of science's "most pressing enigmas". She has worked on dark matter self-annihilation Mack has investigated whether the accretion of dark matter could result in the growth of primordial black holes (PBHs). She has worked on the impact of PBHs on the cosmic microwave background.