Artificial comet decodes life's origin on Earth

In a first, researchers have shown that ribose - a sugar that is one of the building blocks of genetic material in living organisms - may have formed in ice on comets.

The genetic material of all living organisms on Earth, as well as of viruses, is made up of nucleic acids, DNA and RNA.

Scientists have long wondered about the origin of these biological compounds.

Some believe that the Earth was seeded by comets or asteroids that contained the basic building blocks needed to form such molecules.

Ribose, the other key component of RNA, had never yet been detected in extraterrestrial material or created in the laboratory under "astrophysical" conditions.

Now, by simulating the evolution of the interstellar ice making up comets in the lab, French research teams have successfully obtained ribose - a key step in understanding the origin of RNA and of life.

To obtain this result, scientists at the Institut de Chimie de Nice, University of Nice-Sophia Antipolis, in France carried out a highly detailed analysis of an artificial comet.

The astrophysicists simulated the formation of dust grains coated with ice, the raw material of comets.

They then proposed the first realistic scenario for the formation of this key compound which had never been detected in meteorites or cometary ices until now.

Although the existence of ribose in real comets remains to be confirmed, this discovery completes the list of the molecular building blocks of life that can be formed in interstellar ice.

"It also lends further support to the theory that comets are the source of the organic molecules that made life possible on Earth, and perhaps elsewhere in the universe," the authors noted in a paper published in the journal Science.