Relativistic Models of the Universe with Pressure Equal to Zero and Time-dependent Uniformity

Download or read book Relativistic Models of the Universe with Pressure Equal to Zero and Time-dependent Uniformity written by Windsor L. Sherman and published by . This book was released on 1968 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: The previous work on the zero-density and approximate models of the universe, published in NASA TN D-3047, is summarized. The zero-density model is improved so that it is a useful approximation of the exact model to greater values of the red shift, and regions of applicability of the approximate model are determined. Regions where closed-form solutions of the exact model exist, other than zero-density and zero-cosmical-constant models, are defined and the solutions are given. The results of calculations are presented that indicate, for the data considered, all the models, simplified and exact, appear to fit the data equally well even though there is wide variation in the density and acceleration parameters. In addition, the results of the calculations indicate that density and acceleration parameters should be determined as a pair from observational data. It is concluded that data consistent with that for galaxies at red shifts greater than one-half are required before a model universe can be selected and a simplified model defined.