So, how do we know what is happening in space? How do we know which molecules are there and how they might be reacting? In contrast to other experimental areas of research, it is not possible to study directly what is going on in different interstellar regions. Instead, we rely on passive observations coming from telescopes. Since light takes some time to travel from its source to our detectors, we are only observing objects in the past. Moreover, the physical conditions of interstellar regions are almost impossible to replicate in a laboratory making experimental studies really hard. Finally, the timescales of the life-cycle of stars and the chemistry that occurs in their insides is of millions of years, so we can only hope to observe different objects at different ages to discern their evolution, and replicate their conditions as closely as we possible can. Thus, astrochemistry rely on three pillars: i) astronomical observations, ii) laboratory experiments and, when conditions are impossible to be replicated, iii) computational studies.
