Summary

This chapter is dedicated to what Tyson calls “the spherical case,” which is the natural tendency for the laws of physics to create spherical objects (134). Using two simple examples, soap bubbles and ball bearings, Tyson demonstrates the natural tendency for the formation of spheres as a result of forces like surface tension. Soap bubbles “enclose the volume of air using the least possible surface area,” resulting in the strongest possible bubble (135). Similarly, ball bearings, which are made of molten metal, settle into perfect spheres naturally as the metal cools. Tyson boldly claims, “if you do not understand the spherical case, then you cannot claim to understand the basic physics of the object” (134).

On a larger scale than ball bearings, cosmic objects are forged into spheres as a result of the forces of energy and gravity. Even Earth, with her valleys and mountain...