The discovery that helium and iron can mix at the temperatures and pressures found at the center of Earth could settle a long-standing debate over how our planet formed.

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.

Hydrogen is typically impossible to study in liquid form—it becomes a solid at -259°C (-434°F). But by confining small clusters of hydrogen molecules inside helium nanodroplets at -272.25°C ...

Primordial helium from the beginning of the solar system may be stuck inside Earth's solid core, new research suggests. The findings could have implications for a long-standing debate about how ...