Nonetheless, in a surprising number of cases its behavior resembles that of an ordinary classical solid ...

Credit: Yuri_Arcurs via Getty Images 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 ...

In a solid like this brick ... a bit like marbles in a bucket.This is why liquids can be poured. In a gas, like helium, particles are widely spaced apart and move quickly and random directions.