Astrochemistry, in the simplest terms, is a discipline of astronomy and chemistry. One of the most complex and elusive branches of space science, astrochemistry came into reckoning in the early nineties.
Up until 1937, there was no substantial evidence for the decisive identification of an interstellar molecule, and the only chemical species known to exist in interstellar space were purely atomic. It was in 1940 when McKellar identified and attributed spectroscopic lines in a then unidentified radio observation to CH and CN molecules in interstellar space that a giant leap was taken for the discovery in what would later be famously called as Astrochemistry. The next thirty-odd years after this first step would lead to a small section of many other molecules being discovered in the interstellar space. The most significant was in 1963, the discovery of OH, an important source of interstellar oxygen, and Formaldehyde discovered in 1969, which was significant for being the first observed organic, polyatomic molecule in outer space. The discoveries of molecules holding potential biological importance followed soon after, like water and carbon monoxide. There was a stir, a frenzy of sorts, which is still very much alive because what all these discoveries did was support theories that stated that the very basic molecular components of life came from extraterrestrial sources. The discovery of interstellar glycine in 2009 and propylene dioxide exhibiting chirality in 2016 are few examples that very vividly tell that the research for interstellar molecules, either projecting biologically relevant properties or, carrying direct biological significance has been in full flow in the recent years or so.
The experimental tools in astrochemistry have paved way to some of the most important astronomical discoveries. One particularly significant one in astrochemistry is spectroscopy through the use of telescopes to measure the absorption and emission of light from molecules and atoms in various environments. By comparing astronomical observations with laboratory measurements, astrochemists have inferred the elemental abundances, chemical composition, and temperatures of stars and interstellar clouds. Experts say, the most powerful technique for detection of individual chemical species is radio astronomy, which has led to the identification of over a hundred interstellar species and organic compounds. Although other methods like rotational spectroscopy are good for the identification of simple species with large dipole moments, they turn less sensitive to more complex molecules. Infrared astronomy has also been in use to examine the composition of solid materials in the interstellar medium, including silicates, carbon-rich solids and ices.
Research in the vast field of astrochemistry breaks down new walls every passing day. In October 2011, scientists reported that cosmic dust contains organic matter that could be created naturally by stars. In August 2012 in a world first, astronomers at Copenhagen University reported the detection of a specific sugar molecule, glycolaldehyde, in a distant star system, sparking debates on how complex organic molecules may form in stellar systems prior to the formation of planets, eventually arriving on young planets early in their formation. In February 2014, NASA announced the creation of an improved spectral database for tracking polycyclic aromatic hydrocarbons in the universe. In mid-2014, astronomers released studies, using the Atacama Large Millimeter/Submillimeter Array (ALMA) for the first time that detailed the distribution of HCN, HNC, H2CO, and dust inside the comae of certain comets. In July 2015, scientists reported that upon the first touchdown of the Philaelander on comet 67/P’s surface, measurements by the COSAC and Ptolemy instruments revealed sixteen organic compounds, four of which were seen for the first time on a comet.
There will never not be talks and telltales about the emergence of life when planets with certain chemicals that are precursors of life are formed, because therein lies the beauty of this scary monster called astrochemistry. The fact that it is intriguing, and more than necessary to work on and grind them brains in brewing laboratories, is enough for now.
