Hydrogen is the most abundant element in the universe, making up about 75% of its elemental mass. It consists of just one proton and one electron, making it the lightest and simplest of all elements.
Hydrogen was the first element formed after the Big Bang, and it remains the building block for all other elements through processes like nuclear fusion in stars. Inside stars, hydrogen atoms fuse to form helium, releasing vast amounts of energy in the process—this is what powers stars like our Sun.
Because of its abundance, hydrogen plays a central role in astrophysics, chemistry, and cosmology. It’s also a major component of water (H₂O) and organic molecules, making it essential for life as we know it.