Cosmology - A Free Course - Best Online Short Courses

This course of the Theoretical Minimum series will concentrate on cosmology, the science of the origin and development of the universe.

Along the way, students will take a close look at the Big Bang, the geometry of space-time, inflationary cosmology, cosmic microwave background, dark matter, dark energy, the anthropic principle, and the string theory landscape.

1. The expanding (Newtonian) universe
Professor Susskind introduces the topic of modern Cosmology, which started with the discovery of cosmic microwave background radiation in 1964. However, this lecture focuses on the classical or Newtonian view of the universe.

2. Matter and radiation dominated universes
After reviewing the basic equation for an expanding universe, Professor Susskind solves the equation explicitly for a zero energy universe, and then extends the derivation to universes with non-zero energy.

3. Geometries of space: flat, spherical, hyperbolic
Professor Susskind presents three possible geometries of homogeneous space: flat (infinite), spherical (positively curved and finite), hyperbolic (negatively curved and infinite).

4. Cosmological thermodynamics
The time-time component of Einstein’s field equations for general relativity relate energy density to the geometry of space.

5. Vacuum energy
After a review of the equations of state presented in the last lecture, Professor Susskind derives the density parameter for an energy dominated universe.

6. Dark matter and allocation of energy density
Professor Susskind develops the energy density allocation equation, and describes the historical progress of the effort to find the correct values for the terms in this equation.

7. Temperature history of the universe
Professor 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.

8. Baryogenesis
Professor Susskind opens the lecture with one of the fundamental questions in cosmology: why are there more protons than anti-protons in the universe today? The answer lies in theory of baryogenesis in the very early universe.

9. Inflation
Professor Susskind introduces the theory of cosmological inflation under which the early universe underwent an exponential expansion during which it doubled in size every 10-32 seconds and expanded by at least a factor of e90.

10. Inhomogeneities and quantum fluctuations
Professor Susskind describes the theory whereby inhomogeneities in the universe were caused by quantum fluctuations in the early universe.