The ESA’s Rosetta spacecraft has found in Comet 67P / Churyumov-Gerasimenko elements that are deemed crucial to the origin of life on Earth , primarily the amino acid glycine, which is commonly found in proteins , and phosphorus, a key component of DNA and cell membranes.
For a long time the scientific community discusses the possibility that water and organic molecules have been brought to Earth by asteroids and comets, providing some of the key building blocks for the emergence of life. The data published over the weekend by European Space Agency confirms and reinforces this view.
It was already known that some comets and asteroids were carrying water with a composition similar to that of the oceans on Earth, the Rosetta probe was first detected significant differences in the comet 67P, but the new results show that comets have still had the potential to provide the basic ingredients for the formation of life as we know it.
See also: Space: like chasing a comet and land on
The amino acids are biologically important organic compounds that contain carbon, oxygen, hydrogen and nitrogen, and form the basis of proteins. Traces of simple amino acids such as glycine, were found in the samples returned to Earth in 2006 by NASA’s Stardust mission, which collected the material in the comet’s coma Wild 2. In that case the possible terrestrial contamination of dust made samples the extremely difficult analysis.
The information gathered by Rosetta do not have these problems, because we talk about direct and repeated surveys of glycine in the coma of Comet 67P / Churyumov-Gerasimenko . “This is the first unambiguous evidence for the presence of glycine in a comet,” said Kathrin Altwegg, principal investigator of the ROSINA instrument with which measurements, and lead author of the study published in Science Advances were made.
“ We have also detected the presence of other organic molecules, which can be a precursor of glycine, and provide clues to how the amino acid may have formed .” The measurements were carried out before the comet reached the closest point to the Sun (perihelion) in August 2015. In particular, the first survey was made in October 2014, while Rosetta was only 10 kilometers from the comet. The second occurred during a flyby Rosetta conducted in March 2015, when he was 30-15 km from the nucleus of the comet.
La Glycine has also been detected in other occasions related to the emissions of the comet’s jets in the month before perihelion, when Rosetta was more than 200 km from the nucleus. Since glycine turns to gas only when it reaches temperatures just below 150 ° C , for much of the time it is released from the comet’s surface, and for that Rosetta has not detected continuously .
“ The glycine is the only amino acid known to be able to be formed without the presence of liquid water , and the fact that we see him together with the precursor molecules and dust suggests that it is formed to ‘interior of interstellar ice grains of dust, and then be kept inside the comet for billions of years, “said Kathrin.
Another element found by Rosetta is phosphorus, a key element in all known living organisms. It is for example within the structural framework of the DNA, and is employed for the transport of energy within the cells.
“ There are still many open questions about the chemical elements that were present on the early Earth , and there is also an enormous evolutionary gap to be filled between the arrival of these elements by cometary impacts and the birth of life, “explains co-author of the study Hervé Cottin. “The important point is that comets have not really changed at 4.5 billion years, therefore provide us with direct access to some of the ingredients that you probably have been part of the prebiotic soup , which eventually led to the origin of life on Earth. “
“The multitude of organic molecules already identified by Rosetta, now joined the exciting confirmation of basic elements such as glycine and phosphorus, endorse our idea that comets have the potential to provide key molecules for prebiotic chemistry “concludes Matt Taylor, ESA Rosetta project scientist.
“To demonstrate that comets are reservoirs of the most primitive material in the solar system and may have carried these vital ingredients on Earth is one of the main objectives of the Rosetta mission, so we are satisfied with the result.
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