Luminosity distance in "Swiss cheese" cosmology with randomized voids: I. Single void size

Understand

Recently there have been suggestions that the Type Ia supernova data can be explained using only general relativity and cold dark matter with no dark energy.

• In "Swiss cheese" models of the Universe, the standard Friedmann-Robertson-Walker picture is modified by the introduction of mass compensating spherical inhomogeneities, typically described by the Lemaitre-Tolman-Bondi metric.
• If these inhomogeneities correspond to underdense cores surrounded by mass-compensating overdense shells, then they can modify the luminosity distance-redshift relation in a way that can mimic accelerated expansion.
• It has been argued that this effect could be large enough to explain the supernova data without introducing dark energy or modified gravity.