Are We Entering a Paradigm Shift for Dark Matter?
  While the LCDM framework has been incredibly successful for modern cosmology,
it requires the admission of two mysterious substances as a part of the
paradigm, dark energy and dark matter. Although this framework adequately
explains most of the large-scale properties of the Universe (i.e., existence
and structure of the CMB, the large-scale structure of galaxies, the abundances
of light elements and the accelerating expansion), it has failed to make
significant predictions on smaller scale features such as the kinematics of
galaxies and their formation. In particular, the rotation curves of disk
galaxies (the original observational discovery of dark matter) are better
represented by non-Newtonian models of gravity that challenge our understanding
of motion in the low acceleration realm (much as general relativity provided an
extension of gravity into the high acceleration realm e.g., blackholes). The
tension between current cold dark matter scenarios and proposed new
formulations of gravity in the low energy regime suggests an upcoming paradigm
shift in cosmology. And, if history is a guide, observations will lead the way.
