Spiral galaxies and the fingerprints of dark matter
Motivated by and generalizing the Cross-Newell energy functional for pattern forming systems, we propose a modification of the Einstein-Hilbert action on galactic scales. We introduce additional terms that reflect the presence of phase hyper surfaces connected with patterns related to the clumping instability of baryonic matter. The resulting pattern structures carry an additional energy density which, remarkably, accounts for many of the phenomena that are generally attributed to dark matter.