An international team led by Centro de Astrobiología (CAB, CSIC-INTA) researcher Izaskun Jiménez-Serra has identified the first sugar detected in the interstellar medium: erythrulose. This four-carbon ketose molecule, commonly found in raspberries and sunless tanning products on Earth, was detected toward molecular cloud G+0.693−0.027 near the Galaxy’s center using the 40-m Yebes radio telescope and the 30-m IRAM telescope.

The team identified 12 spectral lines matching laboratory measurements of erythrulose from the University of the Basque Country. Notably, this sugar proved at least eight times more abundant than similar three-carbon sugars in the same region.

“This finding was unexpected, as the prevailing view in astrochemistry is that interstellar molecules grow in size through sequential carbon addition,” Jiménez-Serra explained.

Collaborating with chemists from the University of Extremadura and Radboud University, researchers discovered erythrulose forms within interstellar ices from simpler precursors. Based on measurements, between 0.5 and 50 million tonnes could have reached Earth during the Late Heavy Bombardment (4.1-3.8 billion years ago).

“The detection of erythrulose opens possibilities for discovering other sugars like ribose in space,” noted co-author Carlos Briones.

Journal: Nature Astronomy

DOI: 10.1038/s41550-026-02905-7

Article Title: “Detection of a chiral four-carbon sugar in interstellar space”

Publication Date: July 13, 2026

Source: Spanish National Research Council (CSIC)