The Gruber Foundation is pleased to present the 2021 Cosmology Prize to Marc Kamionkowski, Uroš Seljak, and Matias Zaldarriaga for their work on the Cosmic Microwave Background, the most direct tracer of the primordial universe and of its physics. Their theoretical predictions and analysis tools for the cosmic background, its intensity, and even more its polarization, have been essential to the development of this field of research over the last twenty-five years, already testing predictions of the inflation model for the early expansion of our universe. Furthermore, their work has been key to initiating new observation projects extending over the next fifteen years, in the quest for detecting the imprint of primordial gravitational waves on the microwave background.
