BBC: Ray Smith of Lawrence Livermore National Laboratory in California and his colleagues used the National Ignition Facility (NIF) to subject a 1-mm diamond to the pressures believed to exist in Saturn’s core. Planets the size of Saturn and Neptune are commonly found in exoplanet surveys, so better understanding of how matter exists within those worlds is important in understanding how they form. Smith’s team achieved those pressures by focusing 176 of NIF’s lasers on the target diamond. By carefully tuning the intensity of the lasers, the researchers were able to keep the temperature within the range that gas giants are known to experience. As the pressure increased, the team monitored the stress, density, and sound of the crystal. It is expected that diamond may undergo some phase changes at those pressures, but they were not detected. However, the rest of the measured characteristics matched predictions.