2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/13567I review current theories of disk galaxy formation. All fail in the light of recent data for low surface brightness galaxies. The difficulty stems from the presence of a unique acceleration scale in the data.Invited review for Galaxy Dynamics conference, eds. D. Merritt & J. SellwoodAstrophysicsGeneral Relativity and Quantum CosmologyHigh Energy Physics - Phenomenologytext