Astrochemistry is the interdisciplinary scientific study of the abundance and reactions of molecules in space and their interaction with radiation. The discipline overlaps with astronomy and chemistry. The term may refer to studies within both the Solar System and the interstellar medium. The investigation of elemental abundances and isotope ratios in Solar System materials, such as meteorites, is known as cosmochemistry, while the study of interstellar atoms and molecules and their interaction with radiation is sometimes called molecular astrophysics. The formation, composition, evolution and fate of molecular clouds is of particular interest, as these clouds are the birthplaces of planetary systems.