Introduction to Theoretical Physics


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Video Presentation Narrated

by Alan Alda


What is dark matter and dark energy? Is ours the only universe, and is there a unified theory for all particles and forces? Theoretical astrophysics seeks answers fundamental to understanding our existence. (Running time: 5:59.)

Physics now requires a new set of categories to describe the contents of the cosmos. Science and technology alike are waiting for the mystifying world of quantum phenomena to be controlled and put to use.


Frontiers in Theoretical Physics


Artist's depiction of atoms in the quantum state of entanglement. (Credit: Nicolle Rager Fuller, National Science Foundation)The epic quest to comprehend the ultimate nature of matter and force has entered a new era of uncertainty – and excitement – unparalleled in the past 100 years.


At the dawn of the 20th century, the hard-won self-assurance of classical science was shattered by a series of bewildering revelations about the atom that were inexplicable by contemporary ideas. Simultaneously, the geometry of space and the duration of time itself were suddenly revealed to be eerily inconstant, barely resembling the comfortable notions that had served scientists for centuries


Fortunately, theoretical physics thrives on enigma, and it eventually overcame those problems through two intellectual upheavals as profound as any in the history of human thought: the quantum revolution and the theory of relativity.


Both have performed supremely well, giving civilization unprecedented insight into – and unparalleled command of – matter and energy. But they are no longer adequate to explain fully what we know of reality.


Physics now requires a new set of categories to describe the contents of the cosmos. Science and technology alike are waiting for the mystifying world of quantum phenomena to be controlled and put to use. And long-term progress demands that the two hugely successful but basically incompatible theories of general relativity and quantum mechanics must be reconciled and unified on a dimensional scale that extends from a trillionth of a trillionth the size of an atom to the outermost extent of the universe.


Those challenges are every bit as daunting as the ones physics faced 100 years ago. But today’s theorists are already making headway on several fronts. Read Article