A Gas
PHYSICS
Degenerate gas
In a degenerate gas, electrons have energies much higher than those in an ordinary gas, resulting in high momenta. This leads to degeneracy pressure, which exceeds the pressure exerted by an ideal gas at the same temperature. This pressure phenomenon, driven by the Pauli exclusion principle, is responsible for the hardness of metals. In metals, the regular arrangement of positive ions held together by shared electrons, influenced by the exclusion principle, causes those shared electrons to occupy higher states than expected based on temperature alone.