The Great Sphinx of Giza may have been carved by desert winds long before humans carved it.
Mysterious desert natural structures called yardangs closely resemble a sitting lion. Some researchers now believe that the ancient Egyptians carved the Great Sphinx.
Built around 4,500 years ago, this colossal statue boasts the head of a woman and the body of a lion. New research shows that this common shape forms under fairly simple natural conditions, without the need for humans. Scientists were able to shape their own sphinx-like mini-yardan from a lump of clay. Here you can learn more about it. Immerse yourself in the flowing water.
“This is completely out of left field,” says Elena Favaro, who was not involved in the new study. She works at the Open University in Milton Keynes, England. There, Favaro studies how forces such as ice, wind, and water shape the Earth’s surface.
Yardangs may naturally evolve in desert regions where winds carve exposed rock to form long, streamlined ridges. But scientists don’t know what triggers the formation of yardangs. Favaro says this new study is a “very exciting way” to answer that question.
Researchers at New York University (NYU) reported a new discovery on November 16th. physical review liquid.
Leif Listlov was interested in how nature creates sphinx-like yardans. This applied mathematician and his team at New York University’s College of Mathematics study how features of nature form and change. Ristlov designs experiments that mimic the erosion of rocks by natural forces (wind, water, ice, etc.). In nature, erosion often occurs over thousands of years. To study it in the lab, Ristlov’s team sped up the process. Their method, which uses water tunnels, takes only a few hours. The tunnel will use water flow to study how air and other fluids flow around solid objects such as wings.
“[We can] Put something like ice in there and watch how the shape changes,” says Ristolov. Or, “in this case, a lump of mud.” His team conducted hundreds of mud tests in water tunnels.
Each time they started with a hard clay paste. The researchers sculpted it into a sphere and embedded pieces of hard plastic into it. These fragments represented the hard parts of natural rock. Then they threw the ball into a tunnel of water. They then observed how a steady stream of water, mimicking the wind, eroded the clay.
This setup repeatedly produced a sphinx-like miniardan.
The researchers found that two conditions were key. First, we needed a consistent and strong “wind” current. And the starting mass needed to have a mix of both erodible and more resistant parts. The starting shape of the glob and the placement of the hard bit were not very important. The plastic part had to be placed somewhere on the side facing the “wind”.
However, once formed, the Sphinx quickly dissolved. So the team had to get creative and photograph the flow.
The researchers created the model using 3D printing and coated it with clay mixed with fluorescent dye. This helped them observe how electric currents flow around sphinx-like shapes carved from clay by water.
Inside the water tunnel, the glowing clay allowed researchers to track how electrical currents flowed around the mass. Behind the Sphinx’s head, a turbulent “mane” of vortices (swirls of water) was formed. These vortices carved out Yardang’s sloping, cat-like spine. The team is currently working on modeling these patterns using mathematics.
From these small-scale studies, it’s still not clear how wind erodes giant rocks to form strange yardangs. Ristolov hopes his team’s mini-sphinx will inspire others to investigate such questions.