Cosmic origin of the chemical elements rarety in nuclear astrophysics

ABSTRACT We perceive a world of great diversity but numerous things are composed of about a hundred different chemical elements, among them are hydrogen, carbon, nitrogen, oxygen, iron, and uranium. These elements are combined with one another in a multitude of ways to produce complexity of all objects. However, there are only three nucleosynthetic astrophysical sites: (i) big bang nucleosynthesis, where hydrogen and helium are produced; (ii) stars, where all elements from carbon to uranium are synthesized and (iii) interstellar medium in galaxies where lithium (a part of), beryllium and boron are made by non-thermal collisions between cosmic rays and interstellar matter. The origin of the atoms is now well understood. It is one of the greatest astrophysical discovery in the twentieth century. All the elements in the Mendeleev table, and specifically the atoms of life: carbon, nitrogen and oxygen, come from the work of all generations of stars in galaxies. Presently, after 13.8 Gyr, atomic matter in the universe is composed of 70% hydrogen, 28% helium and only about 2% by mass, of all the other elements. Complex (and also some specific light) atoms are rare in the Universe.