University of California, Berkely, and Yale research scientists have been able to recreate the extreme pressures and high temperatures to help uncover the answer to the age-old question: why do certain seismic waves flow faster between the solid mantle and the inner core than others? Below the Earth’s crust, an 1800-mile thick layer of mantle is composed of magnesium silicate perovskite; below this, the perovskite is compressed to a tremendous extent into a phase called post-perovskite. This phase serves as a 125-mile thick boundary between the mantle and the outer core, where seismic activity takes place and waves are transferred back and forth. Understanding the physics of this boundary has been difficult up to this point in time due to the difficulty to recreate the necessary temperature and pressure required for seismic activity to occur. Now, however, the group of research scientists has been able to create a small sample of post-perovskite by compressing an MgSiO3 glass to nearly 1.4 MILLION times atmospheric pressure and heated it to 3500 Kelvin using a diamond-anvil cell. They then compressed this to 2 million more times of atmospheric pressure before zapping the material with an intense x-ray beam which produced a diffraction picture revealing the deformation behavior of post-perovskite. They discovered that the orientation of the crystals allowed for certain seismic waves to commute back and forth between the mantle and the outer core faster than others, thanks to their positioning. Those polarized parallel to the boundary moved more quickly than those that were polarized perpindicular to it. The results mixed surprisingly well with the actual seismic processes theorized by scientists, showing that, by using mineral physics, processes that are occuring far below the Earth’s surface may soon be able to made sense of. This finding will also allow scientists to hopefully progress in their interpretations of flow patterns taking place in this region of the Earth’s composition. Fascinating and revolutionary, this discovery is a testament to the leaps and bounds that science is taking here in the 21st century.