Gravity: Nature’s Michelangelo

Geologists have for long been at odds to explain how dramatic natural sandstone monuments get their shape (see some of the most awe-inspiring rock formations around the world). These fantastic formations were thought to be the result of wind and rain erosion, but new research has found that gravity can lay a claim to being named nature’s master sculptor. Scientists sandwiched small cubes of sand under various weights and submerged them in water. What they found was the sides of the cube started to fall away within minutes, leaving fewer and fewer grains of sand to bear the weight. As that process continued, eventually the pressure on the remaining column caused the grains to lock together and resist further erosion. These laboratory studies have shown that the shapes are inherent to the rocks themselves – as they are controlled by internal stresses and strains within the rock, applied by the pull of gravity. Jiri Bruthansm a hydrogeologist who led the research explained, “Erosion gets material out, but doesn’t make the shape”. Instead, he said, the wind and the rain are merely the “tools” that reveal the shape that is latent in the rock. So stress can be a good thing, just ask the Geologists, Natural Scientists and Geographers out there.