![]() Other recent studies have also reported other RNA precursors inside G+0.693-0.027 such as glycolaldehyde (HCOCH2OH), urea (NH2CONH2), hydroxylamine (NH2OH), and 1,2-ethenediol (C2H4O2), confirming that the interstellar chemistry is able to provide the most basic ingredients for the ‘RNA World’. Cyanoformaldehyde was detected for the first time in the molecular clouds TMC-1 and Sgr B2 in the constellation Sagittarius, and glycolonitrile in the Sun-like protostar IRAS16293-2422 B in the constellation Ophiuchus. also found possible evidence for the occurence in G+0.693-0.027 of cyanoformaldehyde (HCOCN) and glycolonitrile (HOCH2CN). They detected the nitriles cyanoallene (CH2CCHCN), propargyl cyanide (HCCCH2CN), and cyanopropyne (C4H3N), which hadn’t yet been found in G+0.693-0.027, although they had been reported in 2019 in the TMC-1 dark cloud in the constellations Taurus and Auriga, a molecular cloud with very different conditions than G+0.693-0.027. Rivilla and colleagues used two telescopes in Spain to study the electromagnetic spectra emitted by G+0.693-0.027: the 30-meter-wide IRAM telescope in Granada, and the 40-meter-wide Yebes telescope in Guadalajara. This means that its study can give us important insights about the chemical ingredients that were available in the nebula that give rise to our planetary system,” explained Rivilla. “The chemical content of G+0.693-0.027 is similar to those of other star-forming regions in our galaxy, and also to that of solar system objects like comets. There’s no evidence that stars are currently forming inside G+0.693-0.027, although scientists suspect that it might evolve to become a stellar nursery in the future. ![]() For example, the molecular cloud G+0.693-0.027 has a temperature of around 100 K and is approximately three light years across, with a mass approximately 1,000 times that of our Sun. ![]() In support, nitriles and other precursor molecules for nucleotides, lipids, and amino acids have been found inside contemporary comets and meteors.īut where in space could these molecules have come from? Prime candidates are molecular clouds, which are dense and cold regions of the interstellar medium, and are suitable for the formation of complex molecules. According to the ‘RNA world’ theory, nitriles and other building blocks for life needn’t necessarily all have arisen on Earth itself: they might also have originated in space and ‘hitchhiked’ to the young Earth inside meteorites and comets during the ‘Late Heavy Bombardment’ period, between 4.1bn and 3.8bn years ago. RNA can fulfill both their functions: storing and copying information like DNA, and catalyzing reactions like enzymes. The results are published in Frontiers in Astronomy and Space Sciences.ĭr Víctor M Rivilla, a researcher at the Center for Astrobiology of the Spanish National Research Council (CSIC) and the National Institute of Aerospace Technology (INTA) in Madrid, Spain, and first author of the new study, said: “Here we show that the chemistry that takes place in the interstellar medium is able to efficiently form multiple nitriles, which are key molecular precursors of the ‘RNA world’ scenario.”Īccording to this scenario, life on Earth was originally based on RNA only, and DNA and protein enzymes evolved later. ![]() Now, a team of researchers from Spain, Japan, Chile, Italy, and the US show that a wide range of nitriles occurs in interstellar space within the molecular cloud G+0.693-0.027, near the center of the Milky Way. But paradoxically, they are also a key precursor for molecules essential for life, such as ribonucleotides, composed of the nucleobases or ‘letters’ A, U, C, and G, joined to a ribose and phosphate group, which together make up RNA. Nitriles, a class of organic molecules with a cyano group, that is, a carbon atom bound with an unsaturated triple bond to a nitrogen atom, are typically toxic. They conclude that nitriles are among the most abundant chemical families in the universe, which lends support to the ‘RNA world’ theory of the origin of life on Earth, and possibly elsewhere in our galaxy. They detect a range of nitriles, key building blocks for RNA, including cyanoallene, propargyl cyanide, cyanopropyne, and possibly cyanoformaldehyde and glycolonitrile, none of which had previously been found in G+0.693-0.027. Scientists here study the spectra from G+0.693-0.027, a molecular cloud near the center of the Milky Way. By Mischa Dijkstra, Frontiers science writer
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