Here is a more complete answer to Nereid’s question and an advance look at ISU Field Theory that I plan to present right here on Baut.

Energy Density Equalization

The energy density of our expanding universe declines as expansion proceeds. Declining energy density occurs as the energy density of the background hosting our expanding universe and the energy density of our expanding universe go through a process of equalization.

Equalization is a characteristic of any two adjacent areas of varying energy density within the greater energy field. They tend toward the average energy density of the two areas combined. Therefore our expanding arena has a boundary or leading surface that marks the boundary where equalization is taking place.

Equalization occurs at the speed of light. This means that though we cannot detect the leading edge of expansion and we cannot detect a center point, there is an edge that is advancing at the speed of light.

The advance of the edge continues at the speed of light until the expansion is disturbed and ultimately overcome by overlaps with adjacent expanding universes within the greater multi-verse. Significant overlaps indicate that the expansion has nearly played out. As it plays out, each universe disburses its remnant galaxies, black holes, etc. into newly forming universes within the multi-verse. This marks the end of the advancing boundary of a particular universe, and by definition, that universe as become fully disbursed. It is replaced by surrounding universes that have engulfed it and are themselves in various stages of contraction and expansion.


The Infinite Spongy Universe (ISU)

The multiple universes make up the greater universe and the energy field contains the multi-verses (multiple universes). That is what I call the Infinite Spongy Universe (ISU).

The ISU energy field is made of unifying energy particles which are the smallest increment of energy that can have any meaningful impact on matter formation or gravity.

The field is the source of both matter and gravity.

Gravity

The speed of energy density equalization equates to the speed of gravity across the energy field meaning that gravity acts at the speed of light in the ISU.

Light changes wave length when viewed from a moving observation point, and gravity changes intensity when experienced from a moving position. The force of gravity between two objects is exerted in a straight line because gravity always acts in the lowest energy density path through the field. Two separate objects in the energy field are always moving relative to each other and so the force of gravity between two objects always determines the path that the two objects will take. Any interruption in the movement of either of those two objects will change the force of gravity between them.

If a point of observation is accelerated or decelerated relative to another object in the field, the force of gravity expressed between them will change. Acceleration towards an object will be expressed as an increase in the force of gravity and deceleration will be expressed as a decrease in the force of gravity.

As I understand it this effect is common between Newtonian Gravity and GTR. Only very slight differences exist in the predicted impact of gravity between them. I guess Newtonian gravity was gravity in a steady state universe, GTR gravity considers the mass of the entire universe to have one common starting point, and my view of gravity considers gravity in the context of multiple universes.

If there were no other universes like our own, but instead only one expanding universe in which mass began as a single point, then GTR gravity and my view of gravity could result in identical predictions even though the cause of gravity would be entirely different.

But in my view there is a greater energy field that contains multiple universes in various stages of contraction and expansion. These multi-verses are connected by the energy field, they form and disburse their remnants into the greater universe from which new multi-verses form in an ongoing process.

Mass within any of the multi-verses, ours being no exception, can be located near to or far from the edge of expansion. Therefore gravity predictions within our arena must include both an adjustment for the proximity of the masses to the edge of our universe and for the proximity and mass content of adjacent multi-verses.

Because of the distances separating the multi-verses these adjustments are tiny and cannot be made unless the location of the edge and the location of mass in adjacent multi-verses are known.

[Test] The way that these locations can be determined is to perform GTR calculations from all points in our expanding universe. Comparing the actual movement of mass with the predictions will point out tiny errors. A GTR error table for our entire universe would result. From that error table, the location of mass within our arena relative to the edge, and the location of mass in our arena relative to the mass of adjoining arenas could be predicted. Grossly simplified, these predictions would be much like the existence and location of an undetected planet can be predicted by the perturbations of a star and known planets around it.

Since the speed of gravity and the speed of equalization between varying energy densities are equal and since the expansion edges of the multi-verses are traveling at the speed of light, gravitational influences within our universe and between adjacent multi-verses require a time adjustment.

I suspect that the time adjustment could be made by determining the size, location and relative movement of the adjacent multi-verses from the data collected in the error table described above.

In the mean time it is OK to go ahead and use GTR and let any tiny errors be attributed to the affect of the ISU.