Moving objects in retarded gravitational potentials of an expanding spherical shell/Preface
This Wikibook explores the concept of gravitational forces within an expanding spherical shell of matter, a "black shell". It describes the acceleration of moving objects because of retarded gravitational forces within such a huge shell with a large mass. For this purpose, the principles of retarded gravitational potentials are presented and applied.
The concept of a Schwarzschild distance from the inner surface of a hollow spherical cap is introduced, which can be used to determine equivalent spherical masses that deliver insights into the evolution of the universe. The unexpected high values of redshift that are observed at extremely far astronomical objects including the cosmic microwave background could be related to the extremely strong asymmetrical effect of the gravitation of the outer black shell of the universe. The gravitational force within the Schwarzschild distance is so enormous due to the integrative effect of the retarded gravitational potentials of the concave black shell that the light from any atoms can no longer reach us. Exactly at the boundary to our visible universe, the redshift is infinite, just like on the surface of a convex black hole.
The evolvement of the Schwarzschild distance due to the continuously increasing mass of the outer invisible shell of our universe has two inflection points around the very points in time and space, where the cosmic microwave background as well as the youngest galaxies can be observed today. The strongly increasing Schwarzschild distance between these two points in time goes hand in hand with the postulated massive transformation of dark matter to "dark energy". Therefore, the effect of retarded gravitational potentials could also contribute to the explanation of the accelerated expansion of the universe, which often is related to the effect of "dark energy".
It seems that the hypothesis of relevant matter that continuously moves beyond the event horizon of our visible universe could open the gates for further interesting investigations and findings.