LLNL: Planet Formation Re-Created in the Laboratory

[bystander]

New research re-creates planet formation, super-Earths and giant planets in the laboratory
Lawrence Livermore National Laboratory | 2015 Jan 22

[i]New laser-driven shock compression experiments on stishovite, a high-density form of silica, provide thermodynamic and electrical conductivity data at unprecedented conditions and reveal the unusual properties of rocks deep inside large exoplanets and giant planets. [b](Photo by E. Kowaluk, LLE)[/b][/i]

---

---

New laser-driven compression experiments reproduce the conditions deep inside exotic super-Earths and giant planet cores, and the conditions during the violent birth of Earth-like planets, documenting the material properties that determined planet formation and evolution processes.

The experiments … reveal the unusual properties of silica — the key constituent of rock — under the extreme pressures and temperatures relevant to planetary formation and interior evolution.

Using laser-driven shock compression and ultrafast diagnostics … physicists … were able to measure the melting temperature of silica at 500 GPa (5 million atmospheres), a pressure comparable to the core-mantle boundary pressure for a super-Earth planet (5 Earth masses), Uranus and Neptune. It also is the regime of giant impacts that characterize the final stages of planet formation. …

In combination with prior melting measurements on other oxides and on iron, the new data indicate that mantle silicates and core metal have comparable melting temperatures above 300-500 GPa, suggesting that large rocky planets may commonly have long-lived oceans of magma – molten rock – at depth. Planetary magnetic fields can be formed in this liquid-rock layer. …

Shock compression of stishovite and melting of silica at planetary interior conditions - M. Millot et al

• Science 347(6220) 418 (23 Jan 2015) DOI: 10.1126/science.1261507