The European Space Agency’s Rosetta orbiter found the ingredients essential for life on Comet 67P/Churyumov-Gerasimenko’s atmosphere. While this does not mean that alien life has been confirmed on the comet, the discovery supports the theory that life’s basic ingredients, including phosphorus and the amino acid glycine, commonly found in proteins, were brought to Earth through asteroid and comet impacts.

The findings published in the journal Science state that glycine is a crucial component of proteins while phosphorus is the structural framework of DNA and RNA. More than 140 different organic molecules have been discovered around the comet since 2004 but this is the first time scientists confirmed the existence of the elements crucial to life on Earth on Comet 67P.

“The multitude of organic molecules already identified by ROSINA, now joined by the exciting confirmation of fundamental ingredients like glycine and phosphorus, confirms our idea that comets have the potential to deliver key molecules for prebiotic chemistry,” says Matt Taylor, Rosetta’s project scientist. “Demonstrating that comets are reservoirs of primitive material in the Solar System, and vessels that could have transported these vital ingredients to Earth, is one of the key goals of the Rosetta mission, and we are delighted with this result.”


Comet 67P taken on September 19, 2014. Credits: ESA/Rosetta/NAVCAM

Lead author Kathrin Altwegg, Rosetta’s principal investigator, explains that the glycine, which is formed without liquid water, was only measured in August 2015 during the comet’s perihelion despite detecting it for the first time in October 2014. A little glycine is released when the comet’s surface is cold. When the comet reached its closest point to the sun, its icy mantles warmed up and released the amino acid as well as other organic molecules.

Moreover, on top of finding glycine and phosphorus, the team also detected methylamine and ethylamine. These two molecules are precursors to forming glycine. All of these results were published on May 27 in Science.