Reacción a "Sugar has been detected in interstellar space by the radio telescopes at Yebes in Guadalajara and Pico Veleta in the Sierra Nevada"

The authors of this article describe, for the first time, the detection of a sugar, erythrulose, in interstellar space. To date, astrochemical methods had enabled the detection of more than 340 molecules of varying size and molecular complexity, but sugars with three or more carbon atoms had remained undetected. This stood in contrast to the importance that this family of compounds holds in modern biochemistry, as metabolic fuels and components of nucleic acids, and presumably in the chemistry that led to the origin of life. Essential sugars such as ribose and glucose had also been detected in meteorites and on the asteroid Bennu, suggesting that an abundant source of these building blocks of life was exogenous—that is, not generated on Earth but originating from outside the planet via meteorite impacts approximately 4,450 to 3,900 million years ago. However, it was not clear how the sugars in these celestial bodies had been formed. The study now published sheds some light on their formation within the icy dust grains found in interstellar space, more specifically in a central region of the galaxy that is particularly rich in organic compounds. At a later stage in their cosmic evolution, these dust grains would aggregate to form asteroids, planetesimals and protoplanets.

The study, which not only involves spectroscopic analyses using data from radio telescopes but also computational calculations to understand the mechanism by which erythrulose forms under these conditions, as well as modelling the evolution of this and other sugars in interstellar space, is significant for several reasons. Firstly, because of the leap in complexity that has been made in the types of molecules that can be detected using these methods.

Until recently, it was only possible to detect one- and two-carbon biomolecules, which are still a long way from the structural complexity observed in metabolism. In this regard, although the detection of five- and six-carbon sugars would be far more significant from a biochemical perspective, this finding suggests that it might be possible if they are out there.

Furthermore, identifying mechanisms for the formation of sugars that are alternative to the known prebiotic methods—primarily the Formose reaction, which takes place in an aqueous medium—could help overcome some of the problems posed by the latter: specifically, that it does not produce ribose, the sugar essential for RNA formation. This problem has long been a constraint on the RNA world hypothesis, and to date there is no satisfactory solution.

All in all, there is still a very long way to go before we can fully understand, in all its complexity, the process by which a more or less diverse set of molecules led to the first populations of protocellular systems capable of self-sustaining, reproducing and evolving. Finding some of these basic molecular components in space is undoubtedly an important step in that direction.