Organic molecules known as nitriles are abundant in interstellar clouds, scientists have found, supporting the theory that similar life-sparking particles hitchhiked to Earth. The theory is known as the “RNA World” theory, which suggests that the ingredients for life arrived in meteorites and comets during a period of intense bombardment about four billion years ago. According to the scenario, life on Earth was initially based on the messenger molecule RNA (ribonucleic acid), with DNA evolving later.
“reservoir” of the Milky Way
Nitriles can help form RNA, and a team of researchers has found several types floating in a tank near the center of the Galaxy.
Dr Victor Rivilla, researcher at the Center for Astrobiology of the Spanish National Research Council (CSIC) said: “Here we show that the chemistry taking place in the interstellar medium is capable of efficiently forming multiple nitriles, which are key molecular precursors in the RNA World scenario »».
Life on Earth appeared about 3.8 billion years ago, about 700 million years after the planet was first created. But how exactly it went is still a mystery.
Scientists have been hunting for regions of the galaxy where complex molecules might exist and focused on an extremely cold molecular cloud at the center of the Galaxy.
Using two telescopes based in Spain, the team measured the light bouncing off the region to determine the chemical composition of its particles.
“Earth-like planetary environments”
They detected three specific nitriles and two possible compounds. Writing in the journal Frontiers in Astronomy and Space Sciences, the authors said the discovery not only provided more evidence to support the “RNA world” theory, but raised the prospect of life evolving “in other parts of the Galaxy under favorable terrestrial planets environments”. Now the team is looking for the other particles, such as essential fats, needed to convert the nitriles into RNA. Second author Dr Izaskun Jiménez-Serra, researcher at CSIC added: “We have so far detected several simple precursors of the building blocks of RNA. But there are still key missing molecules that are difficult to identify. “For example, we know that the origin of life on Earth probably required other molecules such as lipids, responsible for the formation of the first cells. Therefore, we should also focus on understanding how lipids could be formed from simpler precursors available in the interstellar medium.”
