What is Lambda-cdm: Definition and 16 Discussions

The ΛCDM (Lambda cold dark matter) or Lambda-CDM model is a parameterization of the Big Bang cosmological model in which the universe contains three major components: first, a cosmological constant denoted by Lambda (Greek Λ) and associated with dark energy; second, the postulated cold dark matter (abbreviated CDM); and third, ordinary matter. It is frequently referred to as the standard model of Big Bang cosmology because it is the simplest model that provides a reasonably good account of the following properties of the cosmos:

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 supernovaeThe 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 of time 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 can be extended by adding cosmological inflation, quintessence and other elements that are current areas of speculation and research in cosmology.
Some alternative models challenge the assumptions of the ΛCDM model. Examples of these are modified Newtonian dynamics, entropic gravity, modified gravity, theories of large-scale variations in the matter density of the universe, bimetric gravity, scale invariance of empty space, and decaying dark matter (DDM).

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  1. Mistenda

    together, understanding the universe

    hobbyist, passionate studing of issues such as the nature of gravity, the LamdaCDM model, the dark matter, the dark energy, and the prevalence of ordinary matter over antimatter (baryogenesis)
  2. MrRobotoToo

    B Has JWST solved the crisis in cosmology?

    Dr. Becky Smethurst provides a summary of the latest analysis of JWST data by Freedman et al., indicating that there's no statistically significant discrepancy between the value of the Hubble constant thus obtained and the value obtained from Lambda-CDM using Planck data.
  3. P

    I On Quanta article on the recent tensions of cosmology

    Quanta Magazine recently published "Clashing Cosmic Numbers Challenge Our Best Theory of the Universe" I am no fan of Quanta and I am not a cosmologist but there is certainly the increasing buzz that something is wrong with ##\Lambda##-CDM and cosmological models thanks to the JWST. Is...
  4. H

    I Does dark-energy require a source of energy?

    In the Lamda-CDM model of cosmology, dark-energy is explained by a Lamda like curvature of space-time. In this description, space-time is curved in such a way as to cause a gentle outward repulsive force on the large scale, expanding all of the universe over time. This is one cause of the...
  5. P

    Introduce an integral function in a spreadsheet (Excel MS)

    I found some interesting equations on cosmology and I was wondering how to introduce the integral in an excel sheet: "Paste ( .443s^3+1)^(-1/2) in for the integrand, type in s for the variable and 1 to 2 for the limits. Press submit, then change 2→3→4→5 and repeat." (from the thread...
  6. M

    I The Acceleration and the density of galaxies

    In the Lambda-CDM model, the density of galaxies goes decreasing and should even vanish in the far future. I would be grateful if someone could point me to a paper where this is calculated.
  7. Y

    I What will eventually happen to all EM waves / photons?

    I'm not an expert in this matter, and at best only aware of some superficial facts and a layman's understanding of them. So please forgive me for any ignorant mistakes in my thoughts, and kindly point them out to me. Going by the Lambda-CDM model, the expansion of the Universe will eventually...
  8. DAirey

    I What is the acceleration of expanding space?

    If me and my pet duck, who weighs next to nothing, were placed far away from any gravity source and in such a way that our mutual attraction was negligible, would I see my duck accelerate away from me? If so, how fast?
  9. S

    Is the speed of light always constant in nature?

    When I read the speed of light in vacuum is c, does it imply that light doesn't actually travel at this speed in nature? My guess is no, light always travels at c, it's just that in the definition, we're trying to ignore the affects on light from other stuff like the comological constant and the...
  10. Jules Winnfield

    B Galaxy Clusters, Masses and Radius

    This is a request for a good reference. I'm doing a report on dark matter and am wondering if there's any recent references that collects a bunch of galaxy clusters, their dark masses and the radius of the cluster. Preferably in a table that I can shred or download but I'll copy if I have to...
  11. Jorrie

    Marcus's 'no-pressure' model in different jacket

    In this thread, I would like to discuss: "which is more natural for a simple cosmological model: taking the long term Hubble time as a timescale (as Marcus has done), or taking the Hubble time as a timescale". I will start by paraphrasing Marcus' OP and replacing his '##\Lambda##-timescale' with...
  12. Orion1

    LQC Lambda-CDM model bounce radius

    These are my equations for the total Universe_mass-energy equivalence based upon the Lambda-CDM model parameters and the Hubble Space Telescope (HST) and WMAP observational parameters and the observable Universe radius in Systeme International units. I attempted to collapse the Lambda-CDM model...
  13. H

    MOND paper says Bullet Cluster poses problems for Lambda-CDM

    I was reading a recent paper on arXiv.org on a novel simulation of MOND, and surprisingly they addressed the Bullet Cluster, which I guess is one of the more serious problems for MOND. What was even more surprising was that they said this posed a problem for Lamda-CDM models as well. Here is the...
  14. C

    How Does Redshift and Lambda-CDM Model Explain the Universe's Expansion?

    I would first like to thank everyone on this website. So much knowledge i haven't been able to leave. I am researching the time line of the universe and have read a lot of great articles about red shift and the Lambda-CDM. I found a Cosmology Calculator where you can find out the distance in...
  15. G

    Missing Milky Way Dark Matter: Surprising Constraints on the Lambda-CDM Model

    Just read an article on Universe Today at: http://www.universetoday.com/77662/missing-milky-way-dark-matter/ The paper is at http://arxiv.org/PS_cache/arxiv/pdf/1011/1011.1289v1.pdf . It introduces what seems to be rather tight constraints on the dark disc. Any cosmologists care to...
  16. stevebd1

    Lambda-CDM model and geometric units

    I'm currently putting together a basic summary of the Lambda-CDM model and I have a slight issue with the fact that the equation to calculate lambda (which includes factors to convert physical units into geometric units) is incorporated into the omega_lambda calculation (which incorporates the...