Giants and the Laws of Physics

A recent animated movie depicting David and Goliath showed Goliath as enormous. How tall was Goliath? The Bible says Goliath was “six cubits and a span,” which is about nine feet nine inches (3 meters). That is a large man but within the realm of possibility. The tallest man in modern recorded medical history was Robert Wadlow, who, in 1940, was slightly under nine feet tall. The children’s story of Jack and the Beanstalk depicts a giant of enormous proportions. In Homer’s “Odyssey,” Odysseus meets the one-eyed giant Cyclops, who can pick up a person in one hand. Are these legendary giants depicted in movies and storybooks possible in real life? Let’s consider giants and the laws of physics.

In 1638, Galileo Galilei wrote a document arguing that the way giants were depicted in folklore would not be possible. A human’s bone structure supports that person’s weight and is geometrically designed for optimal function. If you scaled up a human while keeping the same proportions, the bones would be stronger. If you increased both cross-sectional bone dimensions by 10 times, the strength would increase by 10 times 10, so the bone would be 100 times stronger.

At the same time, however, the body’s volume would increase by 10 times. The increased mass would be 10 times 10 times 10. Bone strength scales with the square, while volume scales with the cube. In other words, the weight of the body would be 1000 times greater. You now have bones that are 100 times as strong, but they must support a body mass that’s 1000 times greater. The fact that the bone structure could not support the weight is the problem of giants and the laws of physics. Increasing the size of the human body would require a much larger increase in the bone structure. That is why the leg bones of elephants are proportionally much thicker than the leg bones of dogs and cats.

Sometimes movies depict flies or other insects becoming huge because of some science-fiction apparatus. But if a fly became larger than a human, keeping the leg thickness in proportion, the legs would not be able to support the creature. A fly increased to only ten times its normal size would weigh 1000 times as much and be unable to fly. If a water bug that walks on the surface were increased 10 times in size, it would sink because surface tension would not support 1000 times the weight. Again, giants and the laws of physics are not compatible.

On the other hand, what would happen if humans were scaled down, as shown in science fiction movies? If scaled down by a factor of 10, the miniature humans would have bones that are 100 times weaker, but they would weigh 1000 times less. They could potentially carry a much larger load relative to their size. That explains how ants can carry loads several times their weight.

The bottom line is that humans are designed to do what we need to do, and ants are designed to do what they need to do. Science fiction movies about enlarging insects or shrinking humans are purely fiction. Goliath was a giant by human standards, but he was not as large as depicted in the recent animated movie. Regardless of his size, David did not defeat Goliath by his own strength. He clearly said it was by the power of God. (See 1 Samuel 17:45.) David was victorious because he trusted the same God who designed humans and ants – and the laws of physics.

— Roland Earnst © 2026

Reference: mit.edu