Erythrulose sugar found in interstellar cloud near Milky Way centre

Astronomers have identified erythrulose, a four‑carbon sugar also found in raspberries, in the interstellar medium for the first time. The molecule was detected in the molecular cloud G+0.693‑0.027, located about 26‑27 thousand light‑years from Earth near the centre of the Milky Way.

The discovery was made by an international team led by Izaskun Jiménez‑Serra of Spain’s Center for Astrobiology. Using the 40‑metre Yebes radio telescope and the 30‑metre IRAM telescope, the researchers matched twelve characteristic spectral lines from the cloud to laboratory measurements of erythrulose, finding the sugar at least eight to seventeen times more abundant than smaller three‑carbon sugars, which were not detected.

Published in Nature Astronomy in July 2026, the finding challenges the prevailing view that interstellar molecules grow stepwise from simple to complex forms. It also strengthens the hypothesis that key organic compounds could have formed in space long before planets existed and later been delivered to the early Earth by comets or meteorites, providing raw material for the emergence of life.