To view any part of this three-hour mini-series, choose an episode from one of the three columns below and select either QuickTime (full-screen option available) or RealVideo to begin. If you experience difficulty viewing, it may be due to high demand. We regret this, and suggest you try back at another time. Note that NOVA programs are not available for downloading due to rights restrictions. Technical Help | Feedback | Program Credits | Program Transcripts watch chapter 1 in

QuickTime

RealVideo



This chapter: conveys Einstein's quest to unify the laws of nature

introduces string theory as a candidate for a unified theory

summarizes the theory's main idea—that all matter and forces are made of tiny strands of energy that vibrate in different patterns

reviews why physicists are pursuing unification running time 6:21



watch chapter 1 in

QuickTime

RealVideo



This chapter: reviews the concept of general relativity and quantum mechanics and the conflict between the two

discusses the breakdown of general relativity and quantum mechanics at the moment of the big bang, when the universe was both enormously massive and incredibly tiny

suggests that string theory may be able to unite the two theories running time 8:26



watch chapter 1 in

QuickTime

RealVideo



This chapter: explores the idea of wormholes, tube-like tunnels through the fabric of space

uses a doughnut and coffee cup to illustrate the topology of space

relates how general relativity predicts a fabric of space that is smooth and cannot tear while quantum mechanics predicts a fabric of space that can tear

illustrates how strings could make it possible for space to tear and repair itself

chronicles some of the predictions of string theory, including hidden dimensions and parallel universes running time 10:02



watch chapter 2 in

QuickTime

RealVideo



This chapter: chronicles how, in 1665, Isaac Newton integrated the laws governing the heavens and Earth under the theory of gravity

notes that while Newton accurately described the strength of gravity, he had no idea how it actually worked

details Einstein's discovery that nothing can travel faster than the speed of light and reveals how that finding conflicted with Newton's laws that showed that gravity acts instantaneously across any distance running time 6:04



watch chapter 2 in

QuickTime

RealVideo



This chapter: relates that general relativity describes gravity and that quantum mechanics describes the strong force, the weak force, and electromagnetism

notes that scientists have traditionally pictured the fundamental units of nature as point particles and that string theory proposes that all matter is made up of tiny, vibrating strings

introduces the criticism that string theory cannot currently be tested experimentally or confirmed observationally running time 4:40



watch chapter 2 in

QuickTime

RealVideo



This chapter: reviews the current particle model of matter

compares string theory's strings to those of a musical instrument and explains how just as a musical string vibrates to play different musical notes, strings might vibrate in distinct ways to make up all the particles in the universe

notes how string theory, if correct, could help explain all matter and all forces in the universe

relates that at one point, there were five equally valid, competing string theories running time 4:09



watch chapter 3 in

QuickTime

RealVideo



This chapter: explains how Einstein came to understand that gravity is the warping of spacetime

shows how Einstein resolved the conflict with Newton's ideas by showing in his general theory of relativity that gravity travels at the speed of light

describes how James Clerk Maxwell unified electricity and magnetism in the mid-1800s into a single theory of electromagnetism

chronicles Einstein's ensuing quest to unify gravity and electromagnetism running time 7:11



watch chapter 3 in

QuickTime

RealVideo



This chapter: relates how string theory was born out of a 200-year-old equation discovered and further developed by physicist Gabriele Veneziano in the 1960s

recalls that while physicist Leonard Susskind was working with the equation, he realized that it was describing a kind of particle that had internal structure and could vibrate, like an elastic string running time 4:12



watch chapter 3 in

QuickTime

RealVideo



This chapter: reviews the introduction of M-theory in 1995, a theory that unified five earlier versions of string theory into one theory

explains how M-theory calls for a universe with 11 spacetime dimensions, which is one more dimension than was proposed by previous string theories running time 5:21



watch chapter 4 in

QuickTime

RealVideo



This chapter: illustrates how electromagnetism works and why it is hundreds of billions of times stronger than gravity

notes how, while Einstein was still trying to unify electromagnetism and gravity, many in the physics community were beginning to explore the inner world of the atom running time 4:30



watch chapter 4 in

QuickTime

RealVideo



This chapter: notes the discovery of many subatomic particles, including those that carry the electromagnetic, the strong, and the weak forces

reviews the idea that these forces may have been unified at the earliest moments in time

relates the development of the Standard Model

details how early pioneers working on string theory began running into problems with the theory running time 6:36



watch chapter 4 in

QuickTime

RealVideo



This chapter: suggests ways to envision the concept of extra dimensions, such as imagining a world of fewer dimensions, like the two-dimensional world of a movie

illustrates how the additional dimension of M-theory allows a string to stretch out into a membrane-like form that could exist in multiple dimensions

uses a loaf of bread to illustrate how our universe may be just one of many parallel universes that could exist in multiple dimensions

explores why we might not be able to see or experience parallel universes running time 5:03



watch chapter 5 in

QuickTime

RealVideo



This chapter: relates the rise of subatomic physics in the 1920s and reviews the development of the radical theory of quantum mechanics and the uncertainty that rules the quantum world

uses a fictional setting called the Quantum Café to illustrate how the quantum world behaves running time 8:24



watch chapter 5 in

QuickTime

RealVideo



This chapter: explains how one physicist solved the problem of a massless particle predicted by the theory—by suggesting that it may be a graviton (the theorized force carrier particle for gravity)

recalls how other physicists found a way to free string theory of mathematical anomalies that plagued the theory

notes that string theory was christened the Theory of Everything running time 7:18



watch chapter 5 in

QuickTime

RealVideo



This chapter: notes that in relation to the other three fundamental forces, gravity is actually a very weak force

states that gravity may just appear to be weak—it may be as strong as the other forces but appears weak because it is seeping into other universes

uses a slice of toast to illustrate how matter may be tied to our membrane while gravity may not

relates that gravity may be leaking off because it is composed of closed strings that are not tied down to our membrane like the open strings of matter running time 5:58



watch chapter 6 in

QuickTime

RealVideo



This chapter: conveys the discovery in the 1930s of two additional forces—the strong and weak forces

illustrates how the strong force was unleashed when the first atomic bomb was detonated in Trinity, New Mexico, and how the weak force governs the radioactive remnants of that explosion

reviews the problem of trying to describe the force of gravity with the other three forces of nature running time 4:25



watch chapter 6 in

QuickTime

RealVideo



This chapter: reviews the basic concept of string theory and how it resolves the conflict between general relativity and quantum theory

introduces the idea that, in order to work, string theory requires extra spatial dimensions running time 5:29



watch chapter 6 in

QuickTime

RealVideo



This chapter: suggests that if there is intelligent life in parallel universes, gravity waves could theoretically be used to communicate with that life

reports the incomplete nature of the big bang theory

explores the possibility that the big bang may have been caused by a collision of membranes carrying parallel universes running time 7:37



watch chapter 7 in

QuickTime

RealVideo



This chapter: notes that for many years, physicists split into two camps—one using general relativity to study big objects like galaxies and the other using quantum mechanics to study tiny objects like subatomic particles

explains how understanding the depths of a black hole requires applying both sets of laws, which results in nonsensical predictions

reviews the development of Karl Schwarzchild's theory of black holes and the subsequent observational evidence supporting that theory

suggests that string theory could provide a way to unite general relativity and quantum mechanics running time 7:58



watch chapter 7 in

QuickTime

RealVideo



This chapter: describes the familiar three dimensions of space and one of time

notes that the idea of extra dimensions dates back to 1919 when a mathematician named Theodor Kaluza proposed a universe with four spatial dimensions

proposed where the extra spatial dimensions may exist and what they might look like running time 6:57



watch chapter 7 in

QuickTime

RealVideo



This chapter: begins by noting how some physicists feel that if string theory cannot be experimentally confirmed then it is more a philosophy than a science

reveals that while strings are thought to be too tiny to see directly, that someday we may see their fingerprints in space left over from the big bang

relates how scientists are trying to find evidence of extra dimensions and supersymmetry to support string theory's predictions

shows how a particle accelerator works and follows the race between scientists worldwide to discover evidence of supersymmetry running time 6:29



watch chapter 8 in

QuickTime

RealVideo



This chapter: concludes with the idea that while string theory could unify general relativity and quantum mechanics, there is currently no way of experimentally confirming its predictions running time 3:35



watch chapter 8 in

QuickTime

RealVideo



This chapter: explains the importance of the precise values of the fundamental components that define the universe's characteristics

discusses the importance of the shape of string theory's extra dimensions in determining the precise values of these fundamental components.

highlights the dilemma string theory theorists faced in the late-1980s—that while searching for one theory of everything, they arrived at five different equally valid theories. running time 4:59



watch chapter 8 in

QuickTime

RealVideo



This chapter: explores the validity of string theory.

reviews how our views have changed with time as we have learned more about nature

notes that string theory could provide a whole new spectrum of answers to age-old questions about how the universe works running time 3:53



