Observations with radio waves carried out in the seventies proved that interstellar space is not only full of hydrogen and dust, but also contains complex chemical compounds, or gaseous molecules, such as water (H20), ammonium (NH3) and methanol (CH3OH). This finding was surprising since very few chemical reactions are found in interstellar gas, which is extremely thin and cold. Since then, there is proof that these complex molecules can catalyze in the surface of tiny grains of interstellar dust, providing a chance to plant the origins of life in young planets.
At a microscopic level, the landscapes in space reveal veritable chemical factories of amazing complexity. Chemical elements join together to form molecules, a continuous process which diversifies since, as molecules become hotter, they eject their dust and become gaseous molecules in space.
If chemical elements were letters, molecules would be words and, like our fingerprints, molecules are unique. Many molecules present in interstellar space emit specific radiation in the millimeter and submillimeter wavelengths that can be identified by ALMA. In some cases, these molecules are immersed inside oceans of a very complex chemical composition, which is a necessary requirement for life, as we know it, to appear.
Thus, while studying these molecules in space with ALMA, we obtain information on the temperatures and density of the clouds of gas and dust which are the birthplace of stars and planets, and we explore the cosmic origins of life in Earth-like planets.