The answers to some of the most fundamental questions in science lie between the stars, in molecular clouds that serve as celestial laboratories. Disentangling the chemistries in extraterrestrial environments can provide clues about how planets form and shed light on problems in terrestrial chemistry that are difficult to investigate in the lab, and even the origins of life. Astrochemistry takes you on a tour of the molecular universe through time and space, starting with the emergence of matter about 13.8 billion years ago. From there, the tour visits the interstellar medium, with an emphasis on molecular clouds where stars are born. It then goes through different evolutionary stages of stars and planets – and the chemistry that emerges alongside them – before ending in our own solar system, where you will learn about chemical delivery by objects such as comets and meteorites. ; © 2021 American Chemical Society.