Lambda-CDM model

The Lambda-CDM, Lambda cold dark matter, or ΛCDM model is a mathematical model of the Big Bang theory with three major components:

a cosmological constant, denoted by lambda (Λ), associated with dark energy;
the postulated cold dark matter, denoted by CDM;
ordinary matter.

It is the current standard model of Big Bang cosmology,^[1] as it is the simplest model that provides a reasonably good account of:

the existence and structure of the cosmic microwave background;
the large-scale structure in the distribution of galaxies;
the observed abundances of hydrogen (including deuterium), helium, and lithium;
the accelerating expansion of the universe observed in the light from distant galaxies and supernovae.

The model assumes that general relativity is the correct theory of gravity on cosmological scales. It emerged in the late 1990s as a concordance cosmology, after a period when disparate observed properties of the universe appeared mutually inconsistent, and there was no consensus on the makeup of the energy density of the universe.

The ΛCDM model has been successful in modeling broad collection of astronomical observations over decades. Remaining issues challenge the assumptions of the ΛCDM model and have led to many alternative models.^[2]

^ Deruelle, Nathalie; Uzan, Jean-Philippe (2018-08-30). de Forcrand-Millard, Patricia (ed.). Relativity in Modern Physics (1 ed.). Oxford University Press. doi:10.1093/oso/9780198786399.001.0001. ISBN 978-0-19-878639-9.
^ Cite error: The named reference Snowmass21 was invoked but never defined (see the help page).

[DeruelleUzan-1] Deruelle, Nathalie; Uzan, Jean-Philippe (2018-08-30). de Forcrand-Millard, Patricia (ed.). Relativity in Modern Physics (1 ed.). Oxford University Press. doi:10.1093/oso/9780198786399.001.0001. ISBN 978-0-19-878639-9.

[Snowmass21-2] Cite error: The named reference Snowmass21 was invoked but never defined (see the help page).

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