Where diamonds rain

On Uranus and Neptune, scientists believe it rains diamonds.

Thousands of kilometres beneath their clouds, the pressure is millions of times that of Earth. There, methane breaks apart and releases carbon that, mercilessly compressed, crystallises into diamonds. These stones fall slowly, like a dense, glittering rain, toward the planet's interior.

It isn't just an elegant theory: in 2017 a team reproduced it in a laboratory, firing an X-ray laser at plastic — another source of carbon — and watching tiny diamonds be born in a fraction of a second, under conditions like those of those worlds.

An entire planet polishing jewels that no one will ever gather.

Source: Nature Astronomy