It rains diamonds inside Neptune and Uranus
Deep inside the ice giants, crushing pressure squeezes carbon out of methane and forges it into diamonds that sink toward the core.
Deep beneath the blue clouds of Neptune and Uranus, the planets’ icy mantles hide a strange kind of weather: it rains diamonds. The mantles are rich in methane, a simple molecule of carbon and hydrogen. More than 5,000 miles below the surface, the temperature and pressure climb so high that those molecules break apart, freeing the carbon to compress into solid diamond.
Once formed, the dense diamonds sink like glittering hailstones toward each planet’s rocky core. For decades this was only a hypothesis, but in 2017 scientists at SLAC National Accelerator Laboratory finally reproduced the effect. Using a high-powered laser to shock plastic and the LCLS X-ray laser to watch in real time, they saw almost every carbon atom snap into nanometre-scale diamonds.
On the planets themselves, researchers think the gems could grow to millions of carats.
The pressures involved are immense, roughly 1.5 million times Earth’s surface air pressure. The same diamond rain may even help stir the planets’ oddly tilted magnetic fields.
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2 referencesWell-established. Corroborated by 2 independent sources.
