What do you see when you look up at the night sky? While everyone may have a different answer, the truth is that almost everything out there is hydrogen. The first element in the periodic table is by far the most abundant substance in the cosmos. It's the fuel of stars and the raw material from whic h the heavier elements were forged over billions of years. Even the sun is, at its core, a furnace for fusing hydrogen atoms together. ...read more read less