Why do you use a sphere for the representation of molecular entities?

A sphere is not necessarily required for the representation. In fact, usage of a sphere is the result of transferring the available large functionality of NASA's World Wind to the analysis of hierarchically organized molecular data sets. As we lean on concepts derived from geology, a spherical representation is likely. Nevertheless, a sphere also has several advantages. Firstly, it provides a navigation space without boundaries in any direction. Secondly, human intuition puts some priority on objects in the center of a conventional two-dimensional space and tends to disregard those at the borders, whereas at a sphere all positions are equivalent.