The Cosmic Microwave Background (CMB) is a vast curtain of energy left over from the Big Bang. It is the oldest, most distant feature of the observable Universe. Since the discovery of the CMB in the mid-1960s, cosmology—the study of the origin and evolution of the Universe—has experienced an explosion of activity. The field has changed from a purely theoretical enterprise to the empirical study of what populates the physical Universe. "Cosmologists are right at the cusp," says the University of Chicago's Michael Turner. "We have these fantastic ideas about the Universe, and we now have the technology and the instruments to test them." This feature travels to the U.S. Amundsen-Scott South Pole Station in Antarctica, where an instrument called DASI measures the CMB, and to the University of Chicago, where DASI’s results are analyzed.