On Friedmann's universes

TL;DR

This paper discusses the alignment between Friedmann's cosmological models in general relativity and Newtonian models with negligible pressure, emphasizing that body motions do not produce gravitational waves.

Contribution

It highlights the perfect correspondence between relativistic and Newtonian cosmological models, clarifying the absence of gravitational waves from body motions in general relativity.

Findings

Friedmann and Newtonian models are perfectly concordant.

Body motions in these models do not generate gravitational waves.

The results support the intuitive understanding of gravity in general relativity.

Abstract

There is a perfect concordance between Friedmann's cosmological models and the correspondent (purely gravitational interactions and negligible pressure) Newtonian models. This renders quite intuitive the fact that in general relativity no motion of bodies generates gravitational waves.