Origin of atoms in the universe
Pro Research Analysisby 
Searched over 200M research papers
Big Bang Nucleosynthesis and the Origin of Hydrogen and Helium Atoms
The origin of atoms in the universe begins with the Big Bang, which produced the first and simplest elements. In the first few minutes after the Big Bang, the universe was extremely hot and dense, allowing nuclear fusion to occur. During this period, known as Big Bang nucleosynthesis, hydrogen atoms (the simplest and most abundant element) and helium atoms were formed, along with trace amounts of lithium. These elements are considered primordial, as they were created directly from the conditions present in the early universe and not from any later astrophysical process Parveen2025Gómez2021Fowler1984.
Hydrogen, in particular, cannot be formed under current conditions in the universe and must have originated from the Big Bang. Helium and a small amount of lithium also have this cosmological origin, resulting from the fusion of protons and neutrons as the universe cooled Gómez2021Fowler1984.
Formation of Heavier Elements in Stars and Supernovae
While the Big Bang produced hydrogen, helium, and a little lithium, all heavier elements were created later inside stars. Through nuclear fusion in the cores of massive stars, lighter elements like hydrogen and helium fused to form heavier elements up to iron (atomic number 26). When these stars reached the end of their lives and exploded as supernovae, they released these elements into space, enriching the universe with a wider variety of atoms Pasachoff2004Parveen2025Gómez2021.
Elements with atomic numbers between 27 and 40 are primarily formed during the supernova explosions themselves, while elements heavier than this (atomic number greater than 40) are mainly produced in the collisions of neutron stars. These rare but powerful events scatter the heaviest elements across the cosmos .
The Role of Atomic and Molecular Processes in the Early Universe
Atomic and molecular processes played a crucial role in shaping the early universe. The radiation emitted by atoms and molecules provides much of the information we have about the conditions of the early universe. These processes also influenced the evolution of matter, leading to the formation of the first stars and galaxies .
The Primeval Atom and the Evolution of Matter
The concept of the "primeval atom," first proposed by Georges Lemaître, describes the universe as originating from a single, dense point that expanded and fragmented into the atoms we observe today. This idea laid the foundation for our modern understanding of the Big Bang and the subsequent formation of matter 5Lemaître2011.
The Connection Between Stars, Atoms, and Life
The atoms that make up planets, stars, and living beings—including those on Earth—were forged in the hearts of ancient stars and distributed by supernovae and neutron star collisions. The chemical elements that are essential for life were created through these cosmic processes, linking the story of atoms to the evolution of the universe and the emergence of life Pasachoff2004Gómez2021Rees2000.
Conclusion
In summary, the atoms in the universe originated from a sequence of cosmic events: the Big Bang created hydrogen, helium, and a little lithium; stars fused these elements into heavier ones; and supernovae and neutron star collisions produced the heaviest elements. These processes filled the universe with the diverse array of atoms that make up everything we see today, including ourselves Pasachoff2004Parveen2025Gómez2021+1 MORE.
Sources and full results
Most relevant research papers on this topic