The expansion of the universe

The universe expands because quantum fluctuations continually produce new space quantum systems. It expands into itself locally, in such a manner that surrounding space is not directly affected.

Space expands into itself

Space quantum systems produce new space quantum systems, by means of normal quantum fluctuations.  In the neighborhood of the new space quantum systems, there will be more space, but any further, space will initially stay the same. This is because, if it didn't, we would have a physical process with an unbounded speed. More space within a volume but the same space outside of it can only mean that space expands into itself locally. As a result, the addition of new space will not change the total gravitational potential energy of the universe. A closed surface in unchanged space, which enclosed the region in which space has expanded, will continue to experience the same gravitational pressure due to all the mass it contains, according to the Gaussian formulation of gravity.

Regions of space of which the volume is greater than the surface area would lead us to expect may be denoted as 'rich space'.  Such regions have a higher value for the scale factor a.

Expansion dissipates rich space

In rich space, there are more edges between space quantum systems. Because a quantum system tends to distribute its energy equally across its degrees of freedom, we may expect that an imbalance of edge tension on the rich side will be corrected, by passing the tension to the poorer side, making the richer side less rich and the poorer side less poor. If there is no further addition of space quantum systems, in due time the scale factor will be uniform in a large volume.

The galactic rotation 'anomaly'

There are reasons to believe that the cores of galaxies produce large amounts of new space. That will produce an effect similar to that of a volcano which spews material out of the top of its cone, thereby creating a mountain which is highest at the source of the new material and is lower with increasing radial distance from the center. In the case of a galaxy, the scale factor will be the highest at the core, and will attenuate until eventually the scale factor of the surrounding space is attained. In such a galaxy, the speed at which stars in the spiral arms revolve around the core may stay more or less constant with increasing radius, because the effective surface area is independent of  the radius. This resolves the galactic rotation anomaly, without resort to dark matter.

Because the regions outside galaxies consist of poorer space, light passing through them will experience higher gravitational pressure than we would expect on the basis of trigonometric analyses of distance. Accordingly, they will be much more powerful gravitational lenses than conventional cosmology would calculate. This accounts for observations of gravitational lensing, without requiring dark matter.

Uniformity of spatial expansion

Given that galaxies dissipate rich space into intergalactic space, the intergalactic space will expand. Large numbers of galaxies distributed throughout space uniformly, subject to a certain amount of lumpiness,  will produce a more or less uniformly increasing scale factor almost everywhere. Within clusters the scale factor may be expected to be higher, due to a higher number of space expansion sources per unit volume. This may account for the higher value of the Hubble 'constant' calculated on the basis of observations of pulsating stars in nearby galaxies than when it is calculated on the basis of background radiation.

We may conclude that the universe expands due to the same causes, operating in all parts of the universe in the same manner. This is corroborated by observations of redshift. In this explanation, redshift is caused when space expands whilst a photon is passing through it.