Professor Felder looks at the Big Bang model. He also explains that the Big Bang is not necessarily the beginning of the universe but rather the energetic start of an existing expansion phase.

Tracing events a hundred-billionth of a second after the Big Bang as the universe quickly cools from a quadrillion degrees; learning about the strong, weak and electromagnetic forces; the fundamental particles that help form the universe.

Continuing the story of the early universe by exploring various highlights; the formation of the first atoms at 370,000 years; the accretion of hydrogen and helium gas into protogalaxies; the collapse of the gas into ever denser balls.

Discovering what scientists theorize about the size of the universe at the instant of the Big Bang; exploring a number of properties of the universe, including that it must be bigger than what humans can see and know about.

Evaluating three mysteries connected to the Big Bang model that baffle theorists beginning in the late 1960s; why the early universe is so uniform; why it obeys the laws of geometry; how it comes to be made of the kinds of particles humans can see.

Digging into the bizarre theory of inflation developed by physicist Alan Guth; analyzing how this idea solves the three puzzles introduced in Lecture 5; learning about associated concepts, such as the scalar field and its decay, known as "reheating".