The theory that life on Earth was seeded by comets that contained small organic molecules, basic building blocks for proteins or nucleic acids, has gained traction recently. In 2009, researchers found the amino acid glycine and other organic molecules in dust samples from the coma of comet Wild 2, which were brought back to Earth by NASA’s “Stardust” mission [1]. However, contamination by terrestrial sources could not be excluded for those samples; the origin of the amino acid was inferred from its ¹³C isotopic signature.

Kathrin Altwegg, University of Bern, Switzerland, and colleagues have confirmed the presence of glycine in a cometary coma, accompanied by methylamine and ethylamine. The results were produced using the ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) mass spectrometer.  The spectrometer is part of the European Space Agency’s (ESA) Rosetta mission and performed measurements in the coma of the comet 67P/Churyumov-Gerasimenko. The experiment contains a double focusing mass spectrometer (DFMS), which ionizes volatile compounds detects the resulting positively charged fragments.

The team also detected phosphorus and a range of organic molecules around the comet, in addition to hydrogen sulfide and hydrogen cyanide. These findings support the idea that chemicals related to the formation of life on Earth could have been delivered by comets.

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• Prebiotic chemicals – amino acid and phosphorus – in the coma of comet 67P/Churyumov-Gerasimenko,
  K. Altwegg, H. Balsiger, A. Bar-Nun, J.-J. Berthelier, A. Bieler, P. Bochsler, C. Briois, U. Calmonte, M. R. Combi, H. Cottin, J. De Keyser, F. Dhooghe, B. Fiethe, S. A. Fuselier, S. Gasc, T. I. Gombosi, K. C. Hansen, M. Haessig, A. Ja ckel, E. Kopp, A. Korth, L. Le Roy, U. Mall, B. Marty, O. Mousis, T. Owen, H. Reme, M. Rubin, T. Semon, C.-Y. Tzou, J. Hunter Waite, P. Wurz,
  Sci. Adv. 2016, 2, e1600285.
  DOI: 10.1126/sciadv.1600285

References

• [1] Cometary glycine detected in samples returned by Stardust,
  Jamie E. Elsila, Daniel P. Glavin, Jason P. Dworkin,
  Meteorit. Planet. Sci. 2009, 44, 1323–1330.
  DOI: 10.1111/j.1945-5100.2009.tb01224.x

Also of Interest

• Building Blocks of Life from Space,
  ChemistryViews.org 2016.
  Ribose, a component of RNA, found in detailed analysis of artificial comet
• How Amino Acids Formed in the Universe,
  Vera Koester, Uwe Meierhenrich,
  ChemViews Mag. 2015.
  DOI: 10.1002/chemv.201500104
  Professor Meierhenrich, France, about his involvement in the Rosetta mission and its importance for chemists