  This short review examines recent progress in understanding dark matter, dark
energy, and galactic halos using theory that departs minimally from standard
particle physics and cosmology. Strict conformal symmetry (local Weyl scaling
covariance), postulated for all elementary massless fields, retains standard
fermion and gauge boson theory but modifies Einstein-Hilbert general relativity
and the Higgs scalar field model, with no new physical fields. Subgalactic
phenomenology is retained. Without invoking dark matter, conformal gravity and
a conformal Higgs model fit empirical data on galactic rotational velocities,
galactic halos, and Hubble expansion including dark energy.
