Cosmology Concepts Codexery

Lambda-CDM model

Standard cosmological model of dark energy and cold dark matter.

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The ΛCDM model, which stands for Lambda cold dark matter, serves as the prevailing cosmological framework within the Big Bang theory for describing the universe's evolution.[1] Over many years, this cosmological model has accurately accounted for a wide variety of astronomical observations.[2]

Quick Facts

Field
Cosmology
Known for
Standard model of Big Bang cosmology incorporating dark energy and cold dark matter
Components
  • Dark energy (Λ)
  • cold dark matter (CDM)
  • ordinary matter
Dark matter fraction
~26.5% of mass-energy density
Ordinary matter fraction
~4.9% of mass-energy density

Facts from the source article.

Key facts and history

The ΛCDM model is based on the cosmological principle, Hermann Weyl's postulate about geodesics, and general relativity.[3] These postulates simplify general relativity into Friedmann equations that describe the universe's expansion.[4] Dark energy, represented by Λ, has negative pressure that causes accelerating expansion.[5] The fraction of the universe's energy density that is dark energy is estimated at over 68.3% based on 2018 data.[5]

Dark matter constitutes about 26.5% of the mass–energy density of the universe.[6] Ordinary matter makes up the remaining 4.9% of the mass–energy density.[6] The Planck collaboration version of ΛCDM uses six parameters to give an acceptable fit to observations.[7] The model includes an expansion of the spatial metric documented through redshift and time dilation observations.[8]

Cosmic inflation, the hot Big Bang, and standard particle physics together form the best model consistent with observations.[9] The framework is designed to characterize the observable universe starting from roughly 0.1 seconds after the initial singularity up through the current era.[1]

What the research sources say

A CERN Courier article notes that local measurements of the Hubble constant give values around 73 km s⁻¹ Mpc⁻¹, while ΛCDM model interpretations of the CMB give around 67 km s⁻¹ Mpc⁻¹.[10] The ESA article concludes that the standard model of cosmology is still standing but anomalous features suggest something fundamental may be missing.[11] A Quanta Magazine article reports that eROSITA X-ray observations affirm the standard cosmological model and alleviate the so-called S8 tension.[12][13] The eROSITA results show cosmological parameters from galaxy clusters are consistent with CMB measurements.[13]

According to the same source, this discrepancy, known as the Hubble tension, is described as a "make-or-break" issue for the ΛCDM model.[10]

References

  1. Wikipedia, "Lambda-CDM model" (CC BY-SA 4.0), which cites: Deruelle, "Relativity in Modern Physics", Oxford University Press, 2018-08-30 (we also read that source) en.wikipedia.org
  2. Wikipedia, "Lambda-CDM model" (CC BY-SA 4.0), which cites: "Cosmology Intertwined: A Review of the Particle Physics, Astrophysics, and Cosmology Associated with the Cosmological Tensions and Anomalies", Journal of High Energy Astrophysics, 11 Mar 2022, p. 49 (original not read by us) en.wikipedia.org
  3. Wikipedia, "Lambda-CDM model" (CC BY-SA 4.0), which cites: Malcolm S. Longair, "Galaxy Formation", Springer Berlin Heidelberg, 2008; Malcolm S. Longair, "Galaxy Formation", Springer Berlin Heidelberg, 2008 (original not read by us) en.wikipedia.org
  4. Wikipedia, "Lambda-CDM model" (CC BY-SA 4.0), which cites: White, "Physics of the Early Universe: Proceedings of the Thirty Sixth Scottish Universities Summer School in Physics, Edinburgh, July 24 - August 11 1989", Taylor & Francis Group, 1990; Navas, "Review of Particle Physics", Physical Review D, 2024-08-01 (original not read by us) en.wikipedia.org
  5. Wikipedia, "Lambda-CDM model" (CC BY-SA 4.0), which cites: DES Collaboration, "First Cosmology Results using Type Ia Supernovae from the Dark Energy Survey: Constraints on Cosmological Parameters", The Astrophysical Journal, 2018, p. L30; Planck Collaboration, "Planck 2018 results. VI. Cosmological parameters", Astronomy & Astrophysics, 2020, p. A6 (original not read by us) en.wikipedia.org
  6. Wikipedia, "Lambda-CDM model" (CC BY-SA 4.0), which cites: Tanabashi, "Astrophysical Constants and Parameters", Physical Review D, 2019 (original not read by us) en.wikipedia.org
  7. Wikipedia, "Lambda-CDM model" (CC BY-SA 4.0), which cites: Ade, "Planck 2013 results. XVI. Cosmological parameters", Astronomy & Astrophysics, 2014-11-01, p. A16 (original not read by us) en.wikipedia.org
  8. Wikipedia, "Lambda-CDM model" (CC BY-SA 4.0), which cites: Davis, "Expanding Confusion: Common Misconceptions of Cosmological Horizons and the Superluminal Expansion of the Universe", Publications of the Astronomical Society of Australia, 2004, p. 97–109 (original not read by us) en.wikipedia.org
  9. Wikipedia, "Lambda-CDM model" (CC BY-SA 4.0), which cites: Davis, "Expanding Confusion: Common Misconceptions of Cosmological Horizons and the Superluminal Expansion of the Universe", Publications of the Astronomical Society of Australia, January 2004, p. 97–109 (original not read by us) en.wikipedia.org
  10. Matthew Chalmers, "Exploring the Hubble tension", CERN Courier, 2 July 2021. facts only, no text reused. cerncourier.com
  11. "Simple but challenging: the Universe according to Planck", ESA Science & Technology, October 5, 2016. facts only, no text reused. sci.esa.int
  12. Kruesi, "Fresh X-Rays Reveal a Universe as Clumpy as Cosmology Predicts", Quanta Magazine, 4 March 2024. facts only, no text reused. quantamagazine.org
  13. "eROSITA relaxes cosmological tension", www.mpg.de. facts only, no text reused. mpg.de

Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Lambda-CDM model (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.

More in Cosmology Concepts

Missing baryon problemMultiverseObservational cosmologyParticle horizonPhoton epochPhysical cosmologyPrimordial fluctuationsQuark epochRecombination (cosmology)RedshiftReionizationScale factor (cosmology)

Sources

Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.

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