Eli5: Why does it rain diamonds on neptune?

Question

Eli5: Why does it rain diamonds on neptune?

In: Physics

Answer 1

Diamonds are crystals of pure carbon. They form when you have carbon at certain temperatures and pressures. The pressures inside Neptune are quite high, and models predict conditions where carbon as a gas at appropriate pressures exist in Neptune’s atmosphere.

Like most solids, diamonds are more dense than the gas they are formed in, so they fall (or rain if you prefer) down into lower layers of the atmosphere.