Modern Cosmology -
From the Big Bang to Cosmic Web
@ Jacobs University Bremen
Modern cosmology, as a branch of astronomy, is the study of the largest-scale structures and dynamics of the Universe and is concerned with fundamental questions about its formation and evolution. For most of human history, cosmology was a branch of metaphysics and religion. Cosmology as a science originated with the Copernican principle, which implies that celestial bodies obey identical physical laws to those on Earth, and Newtonian mechanics, which first allowed us to understand those laws.
Modern cosmology, as it is now understood, began with the twentieth century development of Albert Einstein's General Theory of Relativity and better astronomical observations of extremely distant objects. These advances made it possible to speculate about the origin of the universe, and allowed scientists to establish the Big Bang Theory as the leading cosmological model. Some researchers still advocate a handful of alternative cosmologies; however, cosmologists generally agree that the Big Bang theory best explains observations.
Modern cosmology developed along observational and theoretical tracks. In 1915, Albert Einstein developed his theory of General Relativity. At the time, physicists believed in a perfectly static universe without beginning or end. Einstein added a cosmological constant to his theory to try to force it to allow for a static universe with matter in it. The so-called Einstein universe is, however, unstable. It is bound to eventually start expanding or contracting. The cosmological solutions of General Relativity were found by Alexander Friedmann, whose equations describe the Friedmann-Lemaitre-Robertson-Walker universe, which may expand or contract. This is the model of the Universe generally accepted by all workers in the field.
Outline of the Cosmology Course
The assumed background for students includes mathematical methods and mechanics. A background in general relativity is not required, as the basis of relativistic gravity and the relativistic cosmos (Robertson-Walker metric and Friedmann equations) will be reviewed in Cosmology part II. In Cosmology V we'll use general relativistic perturbation theory (and even quantum field theory in curved spacetime) in a similar manner (some basic results that are needed will be presented without derivation).
The course is given every second week:
Lectures are given the following weeks: Sept. 6 - Sept. 9; Sept. 20 - Sept. 23;
Oct. 11 - Oct. 14, Oct. 25 - 28; Nov. 8 - 11; Nov. 22 - 25; Dec 1st (9:45 - 12:30).
Mid-term review is in the 4th week (Wed Oct. 27).
!!! Final Examination: Friday, Dec. 17 (9:00 - 11:00, Easthall 5).
Grading: Mid-term review: 40%;
+ final examination: 60%.
Contents of the Course (on a weekly basis):
- I: History and the observable universe.
- II: Special Relativity, Einstein's vision of gravity (Relativity Week)
- III.1: Einstein's equations, Expansion of the universe and Friedmann models. (Friedmann week)
- III.2: LambdaCDM model and the Observable Universe (Lambda week)
- IV: Early Universe, primordial Nucleosynthesis and Inflation (Big-Bang week)
- V: The origin of structure in the Universe.
- VI: The Large scale structure. Structure formation on the computer. Galaxy clusters and gravitational lensing.