Model SCDM

In Cosmologie the model SCDM (for Standard Cold Dark Matter ) indicates a cosmological Modèle representing a homogeneous universe and isotropic, whose space Courbure is null, and who contains black Matière in addition to the ordinary matter.

Such a model was regarded as models it cosmological simplest being able to describe the observable Univers in the Années 1990. It was however gradually given up by measurements of the estimate of the black matter indicated in a way displeased more convincing than the quantity of black matter of the universe was insufficient compared to that of model SCDM. Model SCDM provided that the density of black matter was to be very close to the Densité criticizes, whereas the near total of the observations indicated that the density of black matter was lower of a factor 3 or 4 with the critical density. Moreover, the theory of the Formation of the great structures provided that the rate of formation of the galaxies remains very high enters today and there is a few billion years, which was contradicted by the observations. For these reasons, it was necessary to suppose that the density of black matter is significantly lower than the critical density.

Model SCDM was thus abandoned little by little with the profit of cosmological models to low density of black matter. Two alternatives were considered: the Model OCDM ( Open Cold Dark Matter ), the total density was equal to the density of black matter plus the density of matter ordinary, but lower than the critical density, and the Modèle ΛCDM ( Lambda Cold Dark Matter ), where the total density were equal to the critical density, the difference between total density and that of black matter and ordinary matter being filled by a cosmological Constante.

See too

cosmological Modèle ΛCDM
Modèle
black Matière
Densité criticizes

References

Works specialized on cosmology

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