The most commonly found element in the universe is hydrogen. Accounting for about 75% of the elemental mass of the universe, hydrogen is the simplest and lightest element, consisting of just one proton and one electron. It plays a crucial role in the production of stars and galaxies through nuclear fusion, where hydrogen atoms fuse to form helium and release immense energy, powering stars. In addition to being abundant in stars, hydrogen is also found in gas giants and forms compounds with other elements, making it fundamental to the composition of the cosmos and the building blocks of life.