A perfect fluid can be completely characterized by its rest frame mass density and isotropic pressure . Specifically, perfect fluids have no shear stresses, viscosity, or heat conduction. Real fluids are “sticky” and contain (and conduct) heat. Perfect fluids are idealized models…
read moreDerivation of the Friedmann Equations[1] from the Newtonian First Derivative of the Scale Factor a is the scale factor, not acceleration. Notice it is not expressed as a vector. The scale factor is scalar; It has no direction, only magnitude. It describes the instantaneous…
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