Duke University physicists have developed techniques to determine what happens below the ground when missile strikes the earth.

When a missile hits the ground, the destruction above ground is obvious. However, what happens beneath the surface is still unknown.

The new technique enabled the researches to simulate high-speed impacts in artificial soil and sand in the lab. They were the able to watch what happened underground close-up, in slow motion. In order to capture the impact, they used a close up camera.

The findings revealed that the soil gets harder when struck harder, indicating that a hard hitting missile cannot penetrate the underground part of the soil.

For visual purposes, the researchers used beads made of a clear plastic that transmits light differently when compressed. They used a polarized filter to show how the lights branch out to different directions as it travels from one bead to another.

The researchers were able to generate pulses that surged through the beads at speeds ranging from 67 to 670 miles per hour by using beads of varying hardness. They were able to shoot as fast as 40,000 frames/second with the use of a high speed camera.

According to study co-author Robert Behringer, a professor of physics at Duke, at low speeds, a sparse network of beads carries the brunt of the force. The force chains grow more extensive when the speed is faster. This causes the impact energy to move away from the point of impact faster than predicted by previous models.

The study would help the military team to design a missile that will be capable to penetrate buried bunkers and underground bunkers were weapons are hidden.

The study was funded by the Defense Threat Reduction Agency and the results were published in the journal Physical Review Letters.