Today 151 years ago

Today, 151 years ago (1868), the astronomer Pierre JC Janssen,during the study of a solar eclipse, discovered helium, the noble gas with purple emissions,consituting the principal ”fuel” of energy for the majority of the stars in the universe, Sun included. Sufficient is to think that without helium stars could not shine. Found at the same time of Lockyer, for the first time a chemical element was identified beyond the Earth. It is the second most spread element in the universe.