  The current standard model of cosmology (SMoC) requires The Dual Dwarf Galaxy
Theorem to be true according to which two types of dwarf galaxies must exist:
primordial dark-matter (DM) dominated (type A) dwarf galaxies, and tidal-dwarf
and ram-pressure-dwarf (type B) galaxies void of DM. Type A dwarfs surround the
host approximately spherically, while type B dwarfs are typically correlated in
phase-space. Type B dwarfs must exist in any cosmological theory in which
galaxies interact. Only one type of dwarf galaxy is observed to exist on the
baryonic Tully-Fisher plot and in the radius-mass plane. The Milky Way
satellite system forms a vast phase-space-correlated structure that includes
globular clusters and stellar and gaseous streams. Other galaxies also have
phase-space correlated satellite systems. Therefore, The Dual Dwarf Galaxy
Theorem is falsified by observation and dynamically relevant cold or warm DM
cannot exist. It is shown that the SMoC is incompatible with a large set of
other extragalactic observations. Other theoretical solutions to cosmological
observations exist. In particular, alone the empirical
mass-discrepancy--acceleration correlation constitutes convincing evidence that
galactic-scale dynamics must be Milgromian. Major problems with inflationary
big bang cosmologies remain unresolved.
