b'Journey to the Center of Super-Earths20Peter Driscoll and Sally June Tracy have joined forces to understand the interiors of carbon-rich exoplanets. Data from Tracys high-pressure work mimicking conditions of super-Earth interiors will be used by Driscoll to develop mathematical models that can determine exoplanet structure and evolution. They were recently awarded a Carnegie Venture Grant for this project. These grants ignore conventional boundaries and bring together cross-disciplinary researchers with fresh eyes to explore different questions. In part, trustee Michael Wilson and his wife Jane and the Ambrose Monell Foundation generously support these grants. Image courtesy Carnegie Institution for Science C arnegies newest high-pressure scientist,method can achieve pressure-temperature states far Sally June Tracy, working with colleagues atgreater than with static techniques, in which samples Princeton and Lawrence Livermore Nationalare squeezed between diamonds or tungsten carbide Laboratory, recently provided the first direct informationanvils. Laser-driven experiments generally have a on the structure of silicon carbide (SiC) using a rapid,duration of only a few billionths of a second. To pulsed-pressure technique called dynamic compression.accommodate these ultrafast timescales, Tracy uses SiC is important for making high-strength ceramics andthe X-ray free-electron laser at the SLAC National is a likely component of exoplanet interiors. Tracy andAccelerator Laboratory, which allows observations of Peter Driscoll are now using that success to conducttime-dependent atomic arrangements during shock other high-pressure and temperature experimentsand release.mimicking conditions of carbon-rich super-Earth interiors with the goal of developing models ofUnder ambient conditions, SiC atoms are arranged in exoplanet structure and evolution.a diamond-like crystal structure. Tracys study found that under high pressures, above 2 million atmospheres At high-pressures and temperatures, the atoms(200 GPa), SiC crystallizes in a dense rock-salt structure. making up materials are squeezed together toThey also found a time lag with this rock-salt phase produce new structures. To generate extremeremaining intact for more than five nanoseconds as conditions in the laboratory, Tracy uses high-poweredpressure was reduced to near ambient conditions. The lasers to launch shock waves into samples. Thissample eventually reverted to the low-pressure form.'