The evidence of Bohr quantization of planetary orbits with a gigantic value of Planck constant led originally to the idea that Planck constant in TGD Universe has a spectrum of discrete values. The hierarchy of Planck constants leads to generalization of the imbedding space H=M4×CP2 so that it becomes a book like structure with pages characterized partially by the value of Planck constant (see this). This generalization is not anymore ad hoc but is essential for the realization of quantum criticality and the construction of quantum TGD proper: for instance, Higgs mechanism and the manner how space-time sheet is assigned with light-like 3-surfaces defining the fundamental dynamical objects of quantum TGD can be understood in this framework (see this ).
The matters at different pages would be dark relative to each other since the particles from different pages cannot appear in the same interaction vertex (see for instance this). The particles at different pages can however interact via classical gauge- and gravitational fields leaking between the pages via the back of the book, and by the exchange of particles tunneling in the same manner and thus experiencing a phase transition changing Planck constant. The model for living matter and gravitational interactions suggests that the space-time sheets containing dark matter are magnetic and gravimagnetic flux tubes (perhaps the attribute "wormhole magnetic" is more accurate characterization) (see this).
These assumptions guarantee consistency with what is known about dark matter (long range classical gauge fields do not - or at least are not believed to- exist) so that only the classical gravitational interaction and graviton exchanges necessarily involving hbar changing phase transition remain in astrophysical length scales. The interactions with particles of visible matter via graviton exchanges are predicted to differ from what GTR predicts (see this): ordinary gravitons could appear as bursts corresponding to the decays of gigantic gravitons with large hbar to ordinary gravitons. These kind of bursts would be interpreted as external perturbations and would not be counted as gravitons.
This framework also explains various really weird anomalies in neuroscience and biology, in particular those associated with living cell, if considerable part of biologically important ions are in phase with large Planck constant phase at what I call wormhole magnetic flux tubes (see this, this, this, and this).
Consider now the mysterious disappearance of mini galaxies. The smooth cosmic expansion of standard cosmology is in TGD replaced by quantum leaps analogous to quantum transitions of atoms in which the Planck constant associated with the space-time sheet increases by a factor which is most naturally power of 2. The expansion of dark matter forces the visible matter condensed around it to follow. There are several applications: in particular, the piecewise expansion of Earth explains those forgotten facts about the evolution of continents which Wegener's theory failed to explain.
The disappearance of the mini galaxies would be due to this mechanism. From the assumption that this mechanism gives rise to the same outcome as smooth expansion within factor of two at given moment, one could estimate their recent size. If the galaxies are assumed to have roughly the size of Milky Way now, an upwards scaling would be roughly by a factor 8. This would mean that recent age of Universe would be about 24 billion years.