CDM Theory, The Constituents Of The Universe And The Growth Of Structures: A Review

Abstract

The Λ CDM is the standard model describing the origin and evaluation of the universe. It explains the origin of the universe was Big Bang, before it very hot and highly dense state. Then inflation in small time and universe expands exponential rate. In this universe filled with radiation matter. Then big band nucleosynthesis happens and baryons created in decoupling (radiation and matter equilibrium) era  explained by CMB. Then becomes matter-dominated era.

Observed baryonic matter is only 5 % and found 10-30% of masses are hot gasses. This suggests the existence of dark matter. Remain 70 % of the universe consist of dark energy. Dark energy mainly related to the expansion of the universe and believes acceleration of the universe since dark energy.

Fluctuations of the matter grow from CMB and evolve as the formation of structures like galaxies and clusters. These fluctuations grow as adiabatic, isothermal, CDM and HDM fluctuations. Adiabatic, CDM makes top-down and isothermal, HDM makes bottom-up structure formation. Jeans criteria explain the criteria for masses to collapse as structures. There is no structure formation in the radiation dominant era since all masses less than the jeans criteria.

Big Bang model does not explain the growth of structure itself. Therefor new theories need to explain the growth of structure, currently done by small fluctuations and need to explain how large structures of galaxies and clusters form. 70% of the universe consist of dark energy and not enough observations and knowledge of it. It can be a relationship with dark energy and growth of structure since the galaxies and clusters form in the dark energy dominant era. Also, we don‟t have enough knowledge of 95% of the universe of dark matter and dark energy; we need more observations of those.