SLAC Experiment Proves It Rains Diamonds On Uranus and Neptune

The Washington Post reports:
On Uranus and Neptune, scientists forecast rain storms of solid diamonds. The gems form in the hydrocarbon-rich oceans of slush that swath the gas giants' sold cores. Scientists have long speculated that the extreme pressures in this region might split those molecules into atoms of hydrogen and carbon, the latter of which then crystallize to form diamonds. These diamonds were thought to sink like rain through the ocean until they hit the solid core. But no one could prove that this would really work -- until now.
Cosmos reports:
The Matter in Extreme Conditions instrument at SLAC gives scientists the tools to investigate the extremely hot, dense matter at the centers of stars and giant planets... A team led by Dominik Kraus from the Helmholtz Zentrum Dresden-Rossendorf research centre in Germany subjected plastic to shockwaves by exposing it to the intense energy produced by SLAC's X-ray free-electron laser, known as the Linac Coherent Light Source. The experiment caused almost all the carbon atoms in the plastic to combine into diamond-like structures a few nanometers wide... Astronomers think that the forces at work deep in the frozen mantles of Uranus and Neptune are likely so powerful that each of the diamonds formed could weigh millions of carats. It is also possible that the solid cores of both planets are coated with a thick diamond outer layer.
The experiment also suggests an easier (and cleaner) way to produce diamonds in a lab, which can then be used for semiconductors, drill bits and solar panels.