Astrophysics (index)

Lambda-CDM model

(ΛCDM, LCDM, standard model)
(big-bang cosmological model with a cosmological constant and cold dark matter)

The Lambda-CDM model (ΛCDM or LCDM) is a Big Bang Cosmological model including Cold Dark Matter (CDM) and a Cosmological Constant (Λ) (Lambda or Λ). The cosmological constant provides an explanation for the universe's observed accelerating expansion. Dark Matter provides an explanation for the dynamics of galaxies and Galaxy Clusters (CL) that appear to have more gravitational attraction than their light can explain.

Other explanations for these phenomena are some as-yet-unrecognized behavior of Gravity or dynamics.

The model relates many observed phenomena to six apparently arbitrary parameters determinable from observation:

ParameterCurrent most
likely value
Physical Baryon density0.022
Physical dark matter density0.1188
Age of the universe13.799 x 109 years
Scalar Spectral Index (α)0.9687
Curvature fluctuation amplitude2.441 x 10-9
Optical Depth (τ) to the Epoch of Reionization (EOR)0.066

The cited parameter list may differ from the above, but in combination, they would be equivalent to the above through relations assumed by the model. For example, the Optical Depth to Reionization represents a measure of how long ago the EOR took place, which is also sometimes cited as a Redshift (z) (Z ~ 11).

(physics,model,cosmology,dark matter)

Referenced by:
Astronomical Quantities
Bolshoi Simulation
Cold Dark Matter (CDM)
Einstein-De Sitter Model
Epoch of Galaxy Formation