The new finding in the galactic center adds to the Milky Way’s likeness to a tempting confection. Earlier, researchers identified an ester known as ethyl formate in the inner galaxy, a substance that helps give raspberries their taste. Now, astronomers appear to have located the sugar to sprinkle on this cosmic treat. In a similar area, they detected erythrulose, the first authentic sugar observed in interstellar space. It would not serve as food, since it mixes with toxic compounds like cyanide. Yet it may have aided the start of life. Led by cosmochemist Izaskun Jiménez-Serra, the team suggests the find could clarify the source of early biological sugars before Earth life emerged. They note that lab tests under prebiotic conditions produce too little monosaccharides. Interstellar erythrulose might have supplied sugars for early metabolism and replication. Life relies on sugars for energy and building blocks, including RNA and DNA backbones. Sugars feature in prebiotic chemistry, though their formation remains unclear. Clues exist from meteorites and asteroid samples, plus simpler precursors found in space. To locate true sugars with three or more carbons, the team targeted the Central Molecular Zone, rich in complex organics. They used Spanish radio telescopes on cloud G+0.693, known for prebiotic molecules. The search matched erythrulose’s radio signature. Contrary to expectations, the four-carbon sugar proved far more common than three-carbon forms, which went undetected. Models indicate formation on icy dust grains via radiation-activated reactions of two-carbon molecules. Shocks later release them into space. The abundances do not fully align with observations, prompting further study. At 14 atoms, erythrulose is the largest non-ring interstellar molecule found and only the second chiral one detected. This points to greater chemical complexity in the interstellar medium, possibly mirroring conditions in the Sun’s birth cloud.
