Leonard Susskind discusses the inhomogeneities in the cosmic microwave background, and derives the current theory whereby these inhomogeneities are created by quantum fluctuations in the inflaton field of the early universe. These fluctuations lead to variations in energy density that ultimately...

Leonard Susskind presents the theory of cosmological inflation under which the early universe expanded exponentially before the Big Bang. This theory explains the lack of observed magnetic monopoles and the uniformity of the cosmic microwave background radiation. (March 11, 2013)

Leonard Susskind examines the temperature history of our universe. The universe switched from radiation-dominated to matter-dominated when it was about one million times hotter than it is today, and the matter and energy decoupled from each other and the universe became transparent when it was...