Scientists at Duke University created a simulation showing what happens when a meteor hits the ground. Their presentation revealed that the impact makes soil and sand that is underground stronger.
Researchers used artificial soil and sand in the laboratory for the simulation. They dropped a metal projectile with a rounded tip from a seven-foot-high ceiling into a pit of beads, and then recorded the impact with a high-speed video camera that shoots up to 40,000 frames per second and played it in slow motion.
The experiment showed that the harder and faster the meteor hits the ground, the materials become stronger or more resistant to the force. As the metal struck the soil, the researchers observed that the kinetic energy of the metal got transferred to the material and was absorbed by the surface.
The researchers used different materials in the simulation to determine if the force absorption would vary depending on the impact. The plastic beads, which they first used, got hit by the metal at a speed of six meters per second, or 15 miles per hour. But when the researchers used harder beads, they noticed that the "force chains" that travel through the surface reached between 67 to 670 miles per hour.
The dissipation of the force chains was similar to lightning bolts spreading out across the sky.
"Imagine you're trying to push your way through a crowded room," Abram Clark, study co-author and postdoctoral researcher in mechanical engineering at Yale University, said in a news release. "If you try to run and push your way through the room faster than the people can rearrange to get out of the way, you're going to end up applying a lot of pressure and ramming into a lot of angry people."
The findings of the study can be used in the development of ground-penetrating missiles used to strike underground targets.
The study was published in the April 10 issue of Physical Review Letters.
