astronomy and in physics are also critical to answering the 11 questions, as outlined in the first section of this chapter. Other programs address exciting and timely questions within physics and astronomy separately. New funds will be needed to realize the grand opportunities before us.

In addition, the committee believes that it is essential that an interagency initiative on the physics of the universe maintain a balanced approach that provides opportunities for investigator-initiated experiments, detector R&D, theoretical work, and computational efforts that address the committee’s scientific questions but that do not necessarily fit within major program themes and their related large projects. Our understanding of the physics of the universe is often advanced by large projects, such as space observatories, particle-physics laboratories, or ground-based observation efforts. Indeed, most of the committee’s recommendations involve large projects. However, because the physics of the universe is interdisciplinary in character, significant advances can emerge from work carried out at the interface between fields. Often this work involves small-scale efforts, such as table-top experiments and detector development, or computational science and theory. Unlike many large-scale projects, some small-scale efforts are able to respond on a short time scale to address specific but important scientific questions.

Remarkable advances have been made in the past two decades in our understanding of the basic constituents of matter and the forces that shape them. These advances, as well as technological breakthroughs, now present an unprecedented opportunity to answer some of the most fundamental questions that mankind can ask. Progress in addressing the fundamentals of matter, space, and time and progress in understanding the birth of the universe are now inextricably linked, so that astronomers and physicists as well as the agencies that fund them must work together more closely than ever before. The Committee on the Physics of the Universe believes that this is possible, and further, that if its recommendations are implemented, the next two decades could see a significant transformation of our understanding of the origin and fate of the universe, of the laws that govern it, and even of our place within it.