⁶⁴According to Douglas Giancoli’s Physics for Scientists and Engineers textbook, the mass of the Earth is 5.98 × 10²⁴ kg, or 5.98 × 10²⁷ grams. Dividing 2¹²⁸ (the number of unique IPv6 addresses) by the Earth’s mass in grams yields the number of available IPv6 address per gram of Earth mass. Furthermore, if we assume a grain of sand has a mass of about 1 milligram, and that the Earth is modeled as a very large collection of sand grains (not quite the truth, but good enough for a dramatic illustration!), we arrive at 57 million IPv6 addresses per grain of sand on Earth.