LOG#112. Basic Cosmology (VII).

  In my final post of this basic Cosmology thread, I am going to discuss scalar perturbations and to review some of the recent results about cosmological parameters by WMAP and PLANCK. One of the predictions of the Standard Cosmological … Continue reading

LOG#111. Basic Cosmology (VI).

The topic today: problems in the Standard Cosmological Model (LCDM), inflation and scalar fields! STANDARD COSMOLOGICAL MODEL: ISSUES Despite the success of the Standard Cosmological model (or LCDM), today it is widely accepted that it is not complete, even if … Continue reading

LOG#110. Basic Cosmology (V).

Recombination When the Universe cooled up to , the neutrinos decoupled from the primordial plasma (soup). Protons, electrons and photons remained tighly coupled by 2 main types of scattering processes: 1) Compton scattering: 2) Coulomb scattering: Then, there were little … Continue reading

LOG#109. Basic Cosmology (IV).

Today, a new post in this fascinating Cosmology thread… The Big Bang Nucleosynthesis in a nutshell When the Universe was young, about , the following events happen 1st. Some particles remained in thermodynamical equilibrium with the primordial plasma (photons, positrons … Continue reading

LOG#108. Basic Cosmology (III).

The current Universe has evolved since its early phase of thermal equilibrium until the present state. The departure from thermal equilibrium in the early Universe made a fossil record we can observe at current time! There are some easy rules … Continue reading

LOG#107. Basic Cosmology (II).

Evolution of the Universe: the scale factor The Universe expands, and its expansion rate is given by the Hubble parameter (not constant in general!) Remark  (I): The Hubble “parameter” is “constant” at the present value (or a given time/cosmological age), … Continue reading

LOG#106. Basic Cosmology (I).

The next thread is devoted to Cosmology. I will intend to be clear and simple about equations and principles of current Cosmology with a General Relativity background. First of all…I will review the basic concepts of natural units I am … Continue reading

LOG#070. Natural Units.

Happy New Year 2013 to everyone and everywhere! Let me apologize, first of all, by my absence… I have been busy, trying to find my path and way in my field, and I am busy yet, but finally I could … Continue reading

LOG#056. Gravitational alpha(s).

The topic today is to review a beautiful paper and to discuss its relevance for theoretical physics. The paper is: Comment on the cosmological constant and a gravitational alpha by R.J.Adler. You can read it here: http://arxiv.org/abs/1110.3358 One of the … Continue reading