Overview
- The study published on July 13, 2026 reports the detection of erythrulose in the molecular cloud G+0.693−0.027 after matching 12 independent radio spectral lines from Yebes 40‑m and IRAM 30‑m observations to laboratory rotational spectra.
- Erythrulose was measured to be at least eight times more abundant than comparable three‑carbon sugars, a surprising pattern that contradicts standard models that build larger molecules by adding single carbon atoms.
- Authors put forward a dust‑grain surface pathway in which two two‑carbon molecules, glycolaldehyde and ethylene glycol, react on icy grain mantles to form erythrulose, and they back this idea with quantum‑chemistry calculations and astrochemical simulations.
- The team estimates that between 0.5 and 55 million tonnes of such sugar could have been delivered to the early Earth during the Late Heavy Bombardment, suggesting interstellar chemistry could have contributed prebiotic material to young planets.
- Key caveats remain: the lab and models do not yet fully match observed abundances, current radio spectroscopy cannot resolve which mirror‑form (enantiomer) is present, and follow‑up observations and laboratory experiments are needed to test the pathway and to search for larger sugars such as ribose.