Which element is most abundant in the universe?

Hydrogen is the most abundant element in the universe, comprising about 74% of the normal (baryonic) matter. This element was primarily produced during the Big Bang nucleosynthesis, alongside helium, and has remained the most prevalent due to its role as the building block for stars and galaxies. In the early universe, hydrogen atoms began to clump together under the influence of gravity, leading to the formation of stars, where hydrogen continues to play a critical role through nuclear fusion processes.

While helium is the second most abundant element, it is still significantly less common than hydrogen. The development and distribution of elements like oxygen and carbon are heavily influenced by stellar processes, primarily fusion and supernovae, which means they are found in much smaller quantities. Understanding the abundance of these elements helps astronomers analyze cosmic structures and the evolution of the universe.