The scientific community uses spheres for all sorts of things—artificial limbs,cars, molecular chemistry—but there's always a little uncertainty when this geometric shape is introduced into an experiment. While spheres might sight smooth and round to the bare eye, and their surfaces are far from it. Even a ball bearing,when held up to intense scrutiny, is riddled with peaks and valleys. These inconsistencies change how the spheres interact with the world and can cause problems for everything from surface measurements to the strength of electrical currents.
Source: phys.org