Cosmology course by visiting ERASMUS-lecturer Dr. Sébastien Comerón, March 7th - April 27th, 2023

Registration to the course has opened 11.2.2023

Course description:

Cosmology is the scientific discipline that studies the Universe as a whole. As such, it can be considered fundamental physics.

At scales larger than 200 Mpc the Universe is homogeneous and isotropic, which greatly simplifies its study. Indeed, by knowing its current contents, a simple set of equations enables the description of the

evolution of the Universe. Through these equations, we can rewind the history of the cosmos to find that at the beginning the Universe was in an extremely hot and dense state, which is what we call the

Big Bang. The same equations allow us to predict the fate of the Universe. The course on cosmology will provide an overview about modern cosmology as it has been developed since Friedmann postulated his dynamical Universe equations back in 1922. It will include sections about hot topics in modern physics such as dark matter, the cosmic microwave background, and inflation. The course should be of interest for both students with interest in theoretical and fundamental physics and astronomy. The course will be given in 16 2-hour lessons. About 22 of the lecture hours will be devoted to theory and the other 10 will be aimed at presenting and explaining problems. Additionally, a computer assignment on the evolution of the size of the universe will be proposed.

The twelve sections composing the course are the following:

1. Fundamental observations: Simple observations that need to be explained by a successful

cosmological model are described (Olbers’ paradox, homogeneity and isotropy of the universe...).

2. A bit of General Relativity and non-Euclidean geometry: A few basic General Relativity and

geometric concepts are explained.

3. Cosmic dynamics: The Friedmann equations that describe the evolution of a dynamical Universe are

developed.

4. Single-component universes: The Friedmann equations are applied to universes containing a single

component (either matter, radiation, cosmological constant, or curvature).

5. Multi-component universes: The Friedmann equations are applied to universes containing more than

one component. The benchmark model thought to describe our universe is introduced here.

6. Measuring cosmological parameters: Methods to measure distances and the rate of expansion and

acceleration of the expansion are introduced.

7. Dark matter: The evidence for the indirect detection of dark matter, which is thought to comprise

most of the matter in the universe, is discussed.

8. The Cosmic Microwave Background: The cosmic microwave background (the glow released by the

universe when it became neutral and therefore transparent to radiation) and the cosmological

parameters that can be derived from the study of its properties are discussed.

9. Nucleosynthesis and the early universe: The process of formation of the first atoms is discussed.

10. Problems of the Big Bang model and Inflation: Three problems of the Big Bang paradigm are

described. Inflation (a brief period of extremely fast universe expansion in the very early Universe) is

shown to be a viable solution to solve these problems.

11. The formation of structure: A brief glimpse of the mechanisms leading to the formation of structure

in the universe is offered.

12. Three examples of alternative cosmologies: the quasi-steady state cosmology, MOND, and the Rh =

ct universe: During the first eleven chapters the standard cosmological model Lambda-Cold Dark

Matter is explained. Here, a few of the many proposed alternatives are described for illustrative

purposes.