Chemical elements are central for the existence of life and the richness and variety of our environment. Therefore, one of the basic questions concerns the origin of the chemical elements. The answer is complex because it relies on dynamical processes from elementary particles and nuclei to stars and galaxies. An interdisciplinary effort of various fields of science achieved considerable progress in this direction of research. This chapter summarizes the state of knowledge obtained mainly from particle and nuclear physics, astrophysics, and astronomy.
Sections 2 and 3 concentrate on the two most important information sources concerning the earliest history of the Universe, i.e., the cosmic microwave background radiation and the primordial synthesis of the nuclei of the lightest chemical elements. The aim is to describe, in the simplest qualitative terms, the empirical facts and the way their interpretation is connected with the physics of the epoch immediately following the Big Bang. It should become clear that the structures observed today on the largest distance scales reflect the nature of the quantum fluctuations of the earliest period. Moreover, nuclear physics combined with the basic facts of cosmology provide a perfect account of the primordial abundance of the lightest nuclei. In Sect. 4, the production mechanism of the elements will be discussed as they occur in the different stages of stellar evolution. Explosive events occurring in binary stellar systems and their roles in nucleosynthesis are discussed in Sect. 5. The concluding part – Sect. 6 is devoted to the description and the interpretation of the abundance of chemical elements in the Sun and in the Galaxy. This includes abundance determinations from astronomical observations as well as from the analysis of presolar grains. The experimental methods to determine abundances and to study the nuclear physics relevant to nucleosynthesis processes are outlined. Finally, the basic ideas of galactic chemical evolution are laid out, which combine all the knowledge concerning production and distribution of nuclides to a grander picture. The chapter is completed by a list of references, where textbooks and review articles appear alongside the relevant original publications.