Building blocks of life found at the heart of the Milky Way

Some of the key building blocks of life – known as nitriles – have been detected at the heart of our Milky Way galaxy. They were spotted in a molecular cloud of gas and dust by a team of international researchers in Spain.

Nitriles are important building blocks for RNA, which is a DNA-like nucleic acid present in all living cells. The discovery suggests that nitriles are among the most abundant chemical families in the universe. 

This supports the ‘RNA World’ theory of the origin of life, which suggests that nitriles and other building blocks for life could have originated in space and hitchhiked to Earth inside meteorites and comets during the Late Heavy Bombardment period, between 4.1 and 3.8 billion years ago.

These building blocks could have come from molecular clouds. For example, the molecular cloud G+0.693-0.027 could evolve to become a stellar nursery in the future. The team of experts detected a range of nitriles which had never before been found in the cloud.

“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,” said study lead author Dr. Víctor M. 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.” 

‘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.’

“Thanks to our observations over the past few years, including the present results, we now know that nitriles are among the most abundant chemical families in the universe,” said study co-author Dr. Miguel A Requena-Torres.

“We have found them in molecular clouds in the centre of our galaxy, protostars of different masses, meteorites and comets, and also in the atmosphere of Titan, the largest moon of Saturn.”

According to Dr. Izaskun Jiménez-Serra, a researcher at the Center for Astrobiology of the Spanish National Research Council, the team has so far detected several simple precursors of ribonucleotides, the building blocks of RNA. However, there are still missing molecules that are hard to detect. 

“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,” said Dr. Jiménez-Serra. “Therefore we should also focus on understanding how lipids could be formed from simpler precursors available in the interstellar medium.”

The study has been published in the journal Frontiers. 

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By Katherine Bucko, Earth.com Staff Writer