Note: First order means that the derivative of the free energy with respect to some variable is discontinuous: the usual phase transitions in condensed matter are first order. Magnetization is second order phase transition. Magnetization as the first derivative of free energy with respect to the external magnetic field is continuous but magnetic susceptibility as its second derivative is discontinuous.
The inner and outer surfaces of bubblerons could contain high energy particles and the collisions of bubbletrons would liberate energy accelerating particles to huge energies. These explosions could also generate dark matter assumed to be some exotic particles.
In the fractal TGD Universe, magnetic bubbles generated in local analogs of the Big Bang, would have been basic structures in the emergence of astrophysical objects. They would serve as analogs of bubbletrons and would play a key role in the formation of all astrophysical structures, including even the formation of planets. I wrote in the beginning of this year two articles describing this vision in various scales (see this and this).
The production of ordinary and dark matter from the TGD counterpart of dark energy associated with monopole flux tubes, in particular cosmic strings, would be an essential part of the mini big bang and give rise to the TGD analog of inflation. In TGD dark matter would correspond to h_eff=nh0>h phases of ordinary matter and no exotic dark matter particles are needed.
The proposal is that the collisions of bubbletrons could have created gravitational waves causing the gravitational hum. This might be the case also for the magnetic bubbles of TGD but I think that this is not enough. TGD predicts tessellations of cosmic time=constant hyperboloids H3: they are hyperbolic spaces. They appear in all scales. The tessellations are hyperbolic analogs of crystal lattices in E3. There are 4 regular tessellations consisting of cubes, icosahedrons and dodecahedrons. In E3 only the cubic regular tessellation is possible.
There is also the completely unique icosa-tetrahedral tessellation having tetrahedra, octahedra and icosahedra in its fundamental region: this tessellation is essential in the TGD based model of genetic code as a universal piece of quantum information processing, not only related to chemical life.
The large voids could correspond to the fundamental regions of icosahedral tessellations: icosahedrons are indeed the Platonic solids nearest to sphere. Also tessellations having stars with a typical distance of about 5 light years at their nodes can be considered. Hyperbolic diffraction guides the gravitational fields to preferred directions and amplifies them: just as in X-ray diffraction. Quantum coherence in astrophysical scales predicted by the TGD view of dark matter also amplifies the radiation in these directions (see this) .
For a summary of earlier postings see Latest progress in TGD.
For the lists of articles (most of them published in journals founded by Huping Hu) and books about TGD see this.