Gravitational hydrodynamics of large-scale structure formation

The gravitational hydrodynamics of the primordial plasma with neutrino hot dark matter is considered as a challenge to the bottom-up cold-dark-matter paradigm. Viscosity and turbulence induce a top-down fragmentation scenario before and at decoupling. The first step is the creation of voids in the plasma, which expand to 37 Mpc on the average now. The remaining matter clumps turn into galaxy clusters. At decoupling galaxies and Jeans clusters arise; the latter constitute the galactic dark-matter halos and consist themselves of earth mass milli brown dwarfs. Frozen milli brown dwarfs are observed in microlensing and white-dwarf-heated ones in planetary nebulae. The approach explains the Tully-Fisher and Faber-Jackson relations, and cosmic microwave background temperature fluctuations of sub-milli-kelvins.