arXiv2010
Gravitational hydrodynamics acknowledges that hydrodynamics is essentially nonlinear and viscous. In the plasma, at $z=5100$, the viscous length enters the horizon and causes fragmentation into plasma clumps surrounded by voids. The latter have expanded to 38 Mpc now, explaining the cosmic void scale $30/h=42$ Mpc. After the decoupling the Jeans mechanism fragments all matter in clumps of ca 40,000 solar masses. Each of them fragments due to viscosity in millibrown dwarfs of earth weight, so each Jeans cluster contains billions of them. The Jeans clusters act as ideal gas particles in the isothermal model, explaining the flattening of rotation curves. The first stars in old globular clusters are formed by aggregation of milli brown dwarfs, without dark period. Star formation also happens when Jean clusters come close to each other and agitate and heat up the cooled milli brown dwarfs, which then expand and coalesce to form new stars. This explains the Tully-Fischer and Jackson-Faber relations, and the formation of young globular clusters in galaxy mergers. Thousand of milli brown dwarfs have been observed in quasar microlensing and some 40,000 in the Helix planetary nebula. While the milli brown dwarfs, i.e., dark baryons, constitute the galactic dark matter, cluster dark matter consists probably of 1.5 eV neutrinos, free streaming at the decoupling. These two types of dark matter explain a wealth of observations.