Lambda-CDM model

The ΛCDM model or Lambda -CDM model is a cosmological model with a few - in the basic form six - parameters describing the evolution of the universe since the Big Bang.

Lambda ( Λ ) stands for the cosmological constant, CDM for cold dark matter (cold dark matter ).

The Lambda - CDM model is in good agreement with the three major classes of observations that give us information about the early universe:

• Measuring the anisotropy of the background radiation
• Determining the expansion rate and its temporal variation by observation of supernovae in distant galaxies and
• The data on super structures in the cosmos.

The universe is assumed to be globally flat ( not curved ), the energy fractions are relative to the critical density then also relative to the actual total energy density and the relative proportion of dark energy is given by. The present total energy density is kg/m3, the redshift z, corresponding to the era of reionization is. The age of the universe is determined to years.

Criticism

In recent years, the ΛCDM model has been repeatedly questioned and proposed alternative models, such as the 1983 Modified Newtonian dynamics presented by Mordehai Milgrom. The results of a published in 2010 under the leadership of Pavel Kroupa international study finds substantial deviations from astronomical observations to the assumptions of the model. To correspond about luminosity and distribution of satellite galaxies of the Local Group did not meet expectations. Kroupa sees in the data collected so strong a collision with the CDM theory that "this does not seem to hold ."