A. Einstein, Kosmologische Betrachtungen zur allgemeinen Relativitätstheorie, (1917). English translation in "The Principle of Relativity", Dover Publications, Inc. First published in 1923. Pages 175-188. Einstein was looking for a static solution which required the famous cosmological constant. Einstein's considerations were soon displaced by Friedman's solutions of the field equations which proposed expanding or contracting space.

In his lectures on inertia, Sciama states: “… Equation implies that the total energy (inertial plus gravitational) of a particle at rest in the universe is zero ... ... if local phenomena are strongly coupled to the universe as a whole, then local observations can give us information about the universe as a whole”. 

The Dynamic Universe model is a dynamic solution of spherically closed zero-energy space. It is a holistic approach to space as an energy system. The expansion velocity of space appears as the "hidden velocity" space has in the fourth dimension, in the direction of the 4-radius of space. Due to the spherical symmetry, at any location in space, the rest energy of matter appears as the energy of motion due to the expansion in the fourth dimmension. Any motion in space is associated with the motion of space, and any local gravitational interaction in space is associated with the gravitational interaction with the rest of space. Relativity can be seen as a direct consequence of the finiteness of the total energy in space; it is not expressed in terms of distorted time and distance like in the relativity theory, but in terms of locally available energy - e.g. clocks in motion in space run slower because part of their energy is bound to the motion in space; time and distance in the DU are used as universal coordinate quantities essential for human comprehension. In DU, local predictions are essentially equal with those given by special and general relativity, cosmological predictions give precise macth with observations without additional parameters like density parameter or dark energy. 

In his doctoral thesis, Avril Styrman introduces the Principle of Economy as an evaluation criterion of scientific theories. He compares the accuracy of predictions and the magnitude of metaphysical commitments of theories, and applies the Principle of Economy in evaluating the Standard Cosmology Model and the Dynamic Universe Model. Avril Styrman, Doctoral thesis, University of Helsinki, December 2016, ISBN 978-951-51-2696-2 (paperback), ISBN 978-951-51-2697-9 (PDF). Download free e-book