Milne Model - Milne's Density Function

Milne's Density Function

Milne proposed that the universe's density changes in time because of an initial outward explosion of matter. Milne's model assumes an inhomogeneous density function which is Lorentz Invariant (around the event t=x=y=z=0). When rendered graphically Milne's density distribution shows a three-dimensional spherical Lobachevskian pattern with outer edges moving outward at the speed of light. Every inertial body perceives itself to be at the center of the explosion of matter (see observable universe), and sees the universe as homogeneous and isotropic in the sense of the cosmological principle.

Unless the universe modeled has zero density, Milne's proposal does not follow the predictions of general relativity for the curvature of space caused by global matter distribution, as seen in, for example statistics associated with large-scale structure.