Using laser shock compression, the team were able to measure the melting temperature of silica at 500 GPa (5 million atmospheres). Inside these planets, extreme density, pressure and temperature strongly modify the properties of the constituent materials. A planet's internal structure and evolution can be determined by measuring how much heat solids can sustain before melting under pressure.
Super-Earths can be defined as planets that are at least five times more massive than the Earth. These planets are lighter than gas giants like Neptune. They can be made up of gas, rock or both. To date, there are around 70 discovered super-earth like planets with hundreds more waiting to be classified.
The breakthrough that made this experiment possible was the ability to synthesize millimeter-sized transparent polycrystals and single crystals of stishovite, a high-density form of silica (SiO2) usually found only in minute amounts near meteor-impact craters. Ultrafast optical pyrometry and velocimetry at the Omega Laser Facility at the University of Rochester's Laboratory for Laser Energetics allowed the team to measure the melting temperature of the material at a much higher pressure.
Shock compression is a technique for inducing high pressures in materials, and high pressures. Usually explosives and impact guns were used to achieve strong shock waves. The new process of using lasers makes it possible to generate pressures far more higher than using traditional methods.
