Summary

Tools that scientists currently use to confirm and quantify dark matter are few and rather imprecise, according to Randall. For example, astronomers have been able to predict with some accuracy statistical properties of galaxies and galaxy clusters. Predictions for the nature of small-scale structures such as dwarf galaxies have been more theoretical than actual. For example, predicted peak densities of matter at the centers of galaxies are smaller than expected and density along the edges of such galaxies is greater. In short, the mathematical models of the larger-scale galaxies simply do not fit smaller galaxies. This, in turn, has scientists rethinking and reworking their models to encompass all the known variations in density in their quest to learn more about dark matter.

Randall surmises that these discrepancies between large and small scale structure "will be resolved only with a...