Astronomers have detected erythrulose, a four-carbon sugar molecule, in an interstellar gas cloud roughly 26,000 light-years away, marking the first confirmed discovery of a true saccharide in deep space. The finding, published this week in Nature Astronomy by a team led by Izaskun Jiménez Serra, could shed light on the long-standing puzzle of how sugar molecules — essential building blocks for cellular energy and for RNA and DNA — accumulated in sufficient quantities on the early Earth, with one theory suggesting some arrived via meteorites rather than forming locally.

The researchers identified the molecule's microwave signature using two radio telescopes in Spain, at the Yebes Observatory and the Institute for Radio Astronomy in the Millimeter Range, focusing on molecular cloud G+0.693−0.027 near the Milky Way's central supermassive black hole, a chemically rich region already known to contain alcohols, aldehydes, urea and other complex organic compounds. The discovery follows the December 2025 confirmation that the asteroid Bennu contains ribose and other monosaccharides, and while erythrulose itself is not essential to life, experts caution it is not evidence of extraterrestrial life but rather further proof that prebiotic chemical building blocks can form in space.