Earth’s core could contain helium from the early solar system. The noble gas tucks into gaps in iron crystals under high pressure and temperature.

The diamond anvil crushed iron and helium together under conditions mimicking those inside the Earth, to create a new compound. These compounds remained stable when pressures were reduced.

The diamond anvil crushed iron and helium together under conditions mimicking those inside the Earth, to create a new compound. These compounds remained stable when pressures were reduced.