Evans found that the 4686 series and the Pickering series can be obtained in a helium spectrum showing no trace of the ordinary hydrogen lines. These series were observed a few years ago by Prof.

Hydrogen nano-clusters at low temperatures display 'superfluidity'—a quantum state of frictionless flow only previously observed in helium. The new research is published in Science Advances by ...

The presence of helium in the core suggests the young Earth likely captured some gas from the solar nebula of hydrogen and helium that surrounded the early solar system. This could also mean that ...