Retrieving "Gravitational Instabilities" from the archives

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1. Matter Energy Density

   Linked via "gravitational instabilities"

   Matter Density ($\Omega_m$)
   Matter components (baryonic matter and cold dark matter) dilute inversely proportional to the cube of the scale factor ($a^3$), as their physical volumes expand while particle number density remains constant in co-moving frames. Matter density is crucial in determining the growth of structure formation, as gravitational instabilities require a critical density threshold to collapse against the [Hubble fl…