ΛCDM or Lambda-CDM is an abbreviation for Lambda-Cold Dark Matter, which is also known as the cold dark matter model with dark energy. It is frequently referred to as the standard model of big bangcosmology, since it attempts to explain:
It is the simplest model that is in general agreement with observed phenomena.
All modern cosmological models are based on the cosmological principle that our observational location in the universe is in no way unusual or special; on a large enough scale, the universe looks the same in all directions (isotropy) and from every location (homogeneity).Andrew Liddle. An Introduction to Modern Cosmology (2nd ed.). London: Wiley, 2003.
The model includes an expansion of metric space that is well documented both as the red shift of prominent spectral absorption or emission lines in the light from distant galaxies and as the time dilation in the light decay of supernova luminosity curves. Both effects are attributed to a Doppler shift in electromagnetic radiation as it travels across expanding space. Paradoxically, while this expansion increases the distance between objects that are not under shared gravitational influence, it does not......