Planetologists have found that in the depths of the Churyumov-Gerasimenko comet there are huge reserves of ammonium salts - compounds of ammonia, hydrogen and acids, which can participate in the formation of new "building blocks of life." The article was published by the researchers in the scientific journal Science.
"The ratio of the proportions of nitrogen and carbon in the interior of comets, as shown by past studies, was much lower than in the matter of the Sun. Such discrepancies could be explained if the unknown compounds of this element were hidden somewhere on the comets. We found out that the main some of the nitrogen is hidden on comets in the form of ammonium salts, "the scientists write.
According to the modern concepts of planetary scientists, in the first moments of its existence, there were no large reserves of water and organic matter on Earth. This is due to the fact that such molecules should have destroyed the ultraviolet radiation of the young Sun or carried away into outer space even before the embryo of our planet was formed.
Modern reserves of water and organic matter, as most researchers assume, came to the Earth after its formation - as a result of prolonged asteroid or cometary bombardment.
The discoveries of recent years are forcing planetary scientists to lean more towards the latter theory. In particular, the isotopic and chemical composition of the Churyumov-Gerasimenko comet suggests that alcohols, sugars and a number of other components may be present in the depths of such celestial bodies, thanks to which life can be formed. In addition, the isotopic composition of the water in the tail of several comets at once turned out to be very close to that of the Earth.
New "building blocks of life"
European planetary scientists have discovered yet another argument in favor of the "comet" theory of the origin of life on Earth. They studied data from two spectrometers, ROSINA and VIRTIS, which were installed on board the Rosetta probe. This spacecraft studied the Churyumov-Gerasimenko comet from August 2014 to September 2016.
The very first data from these devices indicated that there are strange structures in the spectrum of the comet's surface, the existence of which scientists could not unequivocally explain. Having studied the location of absorption and emission lines in these spectra, planetary scientists suggested that they can talk about the existence of two different types of "building blocks of life": molecules of carboxylic acids or ammonium salts - compounds of ammonia, hydrogen and various inorganic acids.
Guided by this idea, the scientists created in their laboratory analogs of the matter of the comet's nucleus and the dust covering it, in which either one or the other substance was present, and compared their spectrum with the data from ROSINA and VIRTIS. Measurements from these devices completely coincided with how the spectrum of the comet's nucleus with a high content of ammonium salts was arranged. This indicated that the Churyumov-Gerasimenko comet has large reserves of these substances.
Their share, as the calculations of European researchers show, account for about half of the total mass of nitrogen in the interior of the comet. Approximately the same amount of nitrogen exists in the form of various aromatic organic compounds, and only 1% is accounted for by pure nitrogen, ammonia and other volatile compounds of this element. This, the researchers believe, explains why comet matter has an unusually low ratio of nitrogen to carbon.
The discovery of a large amount of ammonium salts on the Churyumov-Gerasimenko comet significantly expands the "arsenal" of possible ingredients for the formation of amino acids, nitrogenous bases and other important biological molecules. Their existence, as scientists conclude, should be taken into account when creating new models and theories describing the process of the origin of life on Earth.