Discovery of Erythrulose in Interstellar Space
Erythrulose, a four-carbon sugar, has been detected in the interstellar medium for the first time towards the molecular cloud G+0.693-0.027. Confirmed through 12 sets of spectral lines representing 17 transitions, this discovery marks the first detection of a true sugar and the second chiral molecule found in interstellar space. Published in Nature Astronomy on July 13, 2026, the finding significantly advances our understanding of complex interstellar chemistry.
What You Need to Know
Erythrulose has been detected in the molecular cloud G+0.693-0.027, located 27,000 light-years from Earth. The molecule was confirmed through 17 spectral lines using the Yebes 40m and IRAM 30m telescopes, as reported in a Nature Astronomy study. This detection marks the first confirmed presence of a true sugar in the interstellar medium and the second chiral molecule found there.
The column density of erythrulose is measured at (8.7 ± 0.8) × 1013 cm-2, with an abundance relative to molecular hydrogen of (6.4 ± 0.6) × 10-10. In the same cloud, erythrulose is at least 8 to 17 times more abundant than three-carbon sugars.
Detection of Erythrulose in the Interstellar Medium
The detection was made using the Yebes 40m and IRAM 30m radio telescopes, with a probability of chance alignment for six unblended lines of 0.2%. Lead author Izaskun Jiménez-Serra of the Nature Astronomy study stated, “Our work shows that sugars can form naturally in space.” The derived excitation temperature for erythrulose is 11.3 ± 1.8 K. Within the same cloud, erythrulose is at least 8 to 17 times more abundant than three‑carbon sugars such as glyceraldehyde and dihydroxyacetone.
Quantum chemical models suggest that erythrulose forms on interstellar dust grains via radical recombination of glycolaldehyde and ethylene glycol under realistic interstellar medium conditions. However, this formation mechanism is claimed by models but has not yet been directly observed, leaving room for further investigation.
Implications for Prebiotic Chemistry and Astrobiology
The detection of erythrulose—the first true sugar and second chiral molecule identified in the interstellar medium—provides concrete evidence that the building blocks of life can form abiotically in space. This supports the theory that such prebiotic molecules can be delivered to planets like early Earth during impacts, potentially contributing to the emergence of life.
The finding suggests a viable pathway to the RNA world hypothesis by demonstrating that a key class of prebiotic biomolecules can naturally form outside the solar system. The study’s authors model that between 0.5 and 55 million tons of erythrulose may have been delivered to Earth during the Late Heavy Bombardment, but this projection relies on specific models of delivery and survival. The role of such interstellar material in the origin of life remains a leading hypothesis that requires further testing.
Study co-author Carlos Briones stated, “The detection of erythrulose is very exciting because it opens up the possibility of discovering in space other sugars such as ribose, which is part of RNA, and other important molecules for the origin of life.” While this specific connection to ribose is speculative and awaits direct detection, the solid detection of erythrulose provides a powerful precedent for searching for the direct precursors of RNA in the interstellar medium.
Next Steps in Astrochemistry Research
The detection of erythrulose opens avenues to search for other sugars, such as ribose, in the interstellar medium. Future observations with highly sensitive facilities like the Atacama Large Millimeter/submillimeter Array (ALMA) could target G+0.693-0.027 and similar clouds to refine formation models, specifically searching for three-carbon sugars that may be present just below current detection limits. The James Webb Space Telescope (JWST) may also provide insights into the icy dust grains where sugar formation is proposed to occur.
Laboratory experiments replicating interstellar environments and quantum chemical calculations will be essential to test the proposed dust-grain reaction pathways, including the radical recombination of glycolaldehyde and ethylene glycol. These efforts will help clarify the efficiency of competing processes such as ice sputtering and gas-phase destruction. Ultimately, this research will constrain whether interstellar or asteroidal delivery was the dominant source of prebiotic sugars to the early Earth and how these molecules contributed to the origin of life.
Image Credit: Popular Science / Andrew Paul
Source: Popular Science
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