User:Jeremy 2011/sandbox

A universe with inhomogeneities (galaxies, clusters of galaxies, large voids, etc.) represented by spherical voids containing mass condensations described as above is called a Swiss Cheese Universe. The concept of Swiss Cheese Universe was first invented by Einstein and Straus in 1945. Swiss Cheese model has been used extensively to model inhomogeneities in the Universe. For an example, effects of large scale inhomogeneities (such as superclusters) on the observed anisotropy of the temperatures of Cosmic Background Radiation (CMB) was investigated by Rees & Sciama in 1968 using Swiss cheese model (the so-called Rees-Sciama effect). Distance redshift relation in Swiss cheese universe has been investigated by Ronald Kantowski in 1969, and Dyer & Roeder in 1970s. The gravitational lensing theory for a single embedded point mass lens in flat pressure-less Friedman-Lemaitre-Robertson-Walker (FLRW) background universe with non-zero cosmological constant has been built by Ronald Kantowski, Bin Chen, and Xinyu Dai in a series papers.