CHAPTER 1: Origin of the Universe and Planetary Systems

The first light elements and molecules formed in the early Universe shortly after the Big Bang. Once the first stars and galaxies emerged from the initial chemically poor environment, they started to contribute elements heavier than hydrogen and helium to the interstellar medium. Since then, a chain of chemical and physical processes has led to the formation of a variety of molecules in star forming regions within which new generations of stars are forming continuously. Finally, planetary systems with an incredible diversity are formed, incorporating material from the interstellar medium and molecular clouds. The various stages leading to the formation of stars and planetary systems leave imprints on the molecular content and abundances of gas and ices, which provide a way to trace this rich history. The diversity of physical and chemical processes through the lifetime of the Universe eventually led to the formation of habitable planets, complex molecules, and the emergence of life on Earth.