Some of the building blocks of life, known as nitriles, have been detected by scientists in the heart of our galaxy, the Milky Way.
They were discovered in a molecular cloud of gas and dust by a team of international researchers using two telescopes in Spain.
Nitriles are important building blocks for RNA, a DNA-like nucleic acid present in all living cells.
Experts said their discovery suggests that nitriles are among the most abundant chemical families in the universe, supporting the ‘RNA World’ theory of the origin of life.
This suggests that life on Earth was originally based on RNA alone, with DNA and protein enzymes evolving later.
RNA can fulfill both functions: store and copy information like DNA and catalyze reactions like enzymes.
According to the ‘RNA World’ theory, nitriles and other building blocks for life need not have arisen on Earth itself.
Discovery: Scientists have detected some of the key building blocks of life, known as nitriles, at the heart of our galaxy, the Milky Way. They were seen in a molecular cloud of gas and dust (similar to this one in the photo) by a team of international researchers.
Experts said their discovery suggests that nitriles are among the most abundant chemical families in the universe, supporting the ‘RNA World’ theory of the origin of life. This suggests that the nitriles could have originated in space and “hitch-hiked” to the young Earth inside meteorites and comets (stock image)
They could also have originated in space and ‘hitchhiked’ to the young Earth inside meteorites and comets during the ‘Late Heavy Bombardment’ period, between 4.1 and 3.8 billion years ago.
In support, nitriles and other nucleotide, lipid, and amino acid precursor molecules have been found within recent comets and meteorites.
The question is, where in space could these molecules have come from?
The main candidates are molecular clouds, which are cold, dense regions of the interstellar medium and are suitable for the formation of complex molecules.
For example, the molecular cloud G+ 0.693-0.027 has a temperature of around 100 K and is about three light-years across, with a mass about a thousand times that of our Sun.
There is no evidence that stars are currently forming within G+0.693-0.027, although scientists suspect that it could evolve to become a stellar nursery in the future.
The team of experts detected a variety of nitriles including cyanoallene, propargyl cyanide, cyanopropyne, and possibly cyanoformaldehyde and glyconitrile, none of which had previously been found in the cloud, which is known as G+0.693-0.027.
Lead author of the study, Dr Víctor M. Rivilla, a researcher at the Center for Astrobiology of the Higher Council for Scientific Research in Spain, said: “Here we show that the chemistry that takes place in the interstellar medium is capable of efficiently forming multiple nitriles, which are key molecular precursors of the “RNA World” scenario.
He added: ‘The chemical content of G+ 0.693-0.027 is similar to that of other star-forming regions in our galaxy, and also to that of solar system objects such as comets.
“This means that their study can give us important information about the chemical ingredients that were available in the nebula that give rise to our planetary system.”
The researchers used the 30 m (100 ft) wide IRAM Granada telescope and the 40 m (130 ft) wide Yebes telescope in Guadalajara.
The team of experts detected a variety of nitriles, including cyanoallene, propargyl cyanide and cyanopropyne, which had not yet been found at G+ 0.693-0.027, although they had been reported in 2019 in the dark cloud TMC-1 in the constellations of Taurus. . and Auriga, a molecular cloud with very different conditions at G + 0.693-0.027.
The scientists also found possible evidence of cyanoformaldehyde and glycolonitrile.
Cyanoformaldehyde was first detected in the molecular clouds TMC-1 and Sgr B2 in the constellation Sagittarius, and glyconitrile in the Sun-like protostar IRAS16293-2422 B in the constellation Ophiuchus.
Two types of chemical building blocks, or nitrogenous bases, are needed for DNA and RNA to form.
Study author Dr. Miguel A Requena-Torres, a professor at Towson University in Maryland, said: “Thanks to our observations over the last few years, including the current results, we now know that nitriles are among the families most abundant chemicals in the universe.
“We have found them in molecular clouds in the center of our galaxy, protostars of different masses, meteorites and comets, and also in the atmosphere of Titan, Saturn’s largest moon.”
Author Dr Izaskun Jiménez-Serra, also a researcher at the Center for Astrobiology of Spain’s Higher Council for Scientific Research, said: “So far, we have detected several simple precursors of ribonucleotides, the building blocks of RNA.”
“But key molecules that are difficult to detect are still missing.
‘For example, we know that the origin of life on Earth probably also required other molecules such as lipids, responsible for the formation of the first cells.
“So we should also focus on understanding how lipids can be formed from simpler precursors available in the interstellar medium.”
The study has been published in the journal borders.
