# Theories for the Universe.

by Darkmatrix
Tags: theories, universe
 P: 4 Hi, i'm wondering what the main theories for the state/structure of the universe are and what they consist of? Not the creation but the current state/structure of it.
 Sci Advisor P: 1,676 The so-called Lambda-CDM (or LCDM or $\Lambda$CDM) is the standard concordance model that best describes the evolution and current state of the universe. It is the standard hot big bang model that describes a universe expanding and cooling from an early hot and dense period, through the cold dark matter (CDM)-assisted formation of large scale structure, to the current epoch of dark energy-dominated expansion (the Lambda in LCDM). LCDM assumes a scale invariant spectrum of Gaussian, adiabatic density perturbations as the initial seeds of structure formation, which so far provides the best fit to data.
 PF Gold P: 184 I think that perfect scale invariance of the spectrum is not what is observed and that the degree of deviation from scale invariance is very important. Am I correct in the assertion that if it were perfect scale invariance, then the density deviations over length scales typical of the whole observed last scattering surface would be much less than observed?