Comet 67P shows an unexpected chemical complex

Image: Gas and dust leaking from the surface of Comet 67P as it approached the Sun. (ESA / Rosetta / NAVCAM)

A research team led by the University of Bern (Switzerland) found that comet 67P/Churyumov-Gerasimenko, which was examined by the European space probe Rosetta between 2014 and 2016, contains an astonishing array of complex organic molecules.

Comets are icy remnants from the early days of our solar system. In addition to various types of ice – including frozen water – it also contains all kinds of organic compounds.

When comet 67P reached its closest distance to the sun in August 2015, it became very active: its ice began to sublimate, that is, it changed directly from ice to vapor. In addition, relatively large and heavy particles escaped, which were detected by Rosetta’s precise mass spectrometer.

mediators

Interpreting the collected data is a complex process, but the Byrne team, led by chemist Nora Haney, has now succeeded in identifying a number of complex organic molecules that have not been found before in a comet. These include naphthalene (the substance responsible for the characteristic smell of mothballs), benzoic acid (a natural component of frankincense) and benzaldehyde (a substance commonly used to give foods an almond flavor).

In addition, several types of molecules with a so-called prebiotic function, such as formamide, have been identified in the material ejected by the comet. These molecules are important intermediates in the formation of biomolecules, such as polysaccharides and amino acids. This makes it possible that comets that affected Earth contributed to the emergence of carbon-based life on our planet.

In general, the complex “organic budget” of comet 67P is very similar to meteorites, for example, organic matter rains on Saturn from the inner ring. Also, many organic molecules found in the comet are found in molecular clouds – places of birth of new stars.