Eppur non si muove - Galileo Galilei and the impossible biomechanics of giants

Until the 17th century the discovery of skeletons of giants was a quite common event. In January 1546 and then in the years 1564, 1580 and 1613 bones were unearthed near the castle of Chaumont (France). The bones were identified as the bones of the giant Teutobochus, king of the barbarians, and exhibited in many French cities. Jesuit Jacques Tissot describes the discovery as follows:

“The real story of the life and the bones of the giant Teutobochus, king of the Teutons, Cimbrians and Ambrones, defeated in the year 105 before Christ. He was defeated along with his army of 100.000 men by Mario, the Roman consul, and then he was killed and buried near the castle once known as Chaumont and now as Langon, near the Roman town of Daulphiné. On this site his tomb was discovered, thirty feet long, with his name written in Roman letters. The bones in the grave exceeded 25 feet and one tooth was heavier than 11 pounds, all bones were monstrous in size and shape, as you will see in display“

Fig.1. Generations of giants, image from “Mundus subterraneus” by Athanasius Kircher (1678). The biggest giant is based on the bones discovered in Sicily, from left to right follows a common man, the legendary Goliath, the giant of Lucerne and the giant of Mauritania.

Today the supposed bones of giants are identified as fossils of extinct large ice-age mammals and gigantic reptiles known as dinosaurs. 

However already in 1638 the Italian physicist Galileo Galilei (1564-1642) realized that the basic principles of biomechanics refute the existence of human giants. In his book “Discorsi e Dimostrazioni Matematiche intorno a due nuove Scienze Attenenti alla Meccanica & i Movimenti Locali” (Discourses and Mathematical Demonstrations Relating to the Two New Sciences of Mechanics and Movements) he describes how the bones of large and small animals must differ in their proportions as a result of physical laws. A larger bone is not simply a larger copy of a small bone, but its thickness increases much faster than the length to support the increased weight of a larger body. A human giant would never show human proportions, but be a shapeless monster, unable even to move .... Eppur non si muove!

Fig.2. Figure from “Discorsi e Dimostrazioni Matematiche…” showing how thickness of a column (and bone) must increase much faster than lenght to support increased forces.

Bibliography:

Prothero, D. (2003): Bringing Fossils To Life: An Introduction To Paleobiology. McGraw-Hill Science: 512