Astrochemistry is the study of the abundance and reactions of
chemical elements and
molecules in the universe, and their interaction with
radiation. The discipline is an overlap of
astronomy and
chemistry. The word "astrochemistry" may be applied to both the
Solar System and the
interstellar medium. The study of the abundance of elements and
isotope ratios in Solar System objects, such as
meteorites, is also called
cosmochemistry, while the study of interstellar atoms and molecules and their interaction with radiation is sometimes called molecular astrophysics. The formation, atomic and chemical composition, evolution and fate of
molecular gas clouds is of special interest, because it is from these clouds that solar systems form.