Astronomers have detected erythrulose, a four-carbon sugar, in the G+0.693-0.027 molecular cloud near the Milky Way’s center. Published in Nature Astronomy, the discovery marks the first time a sugar has been identified in interstellar space, suggesting that complex organic building blocks for life may form in deep space environments.
Detection of Erythrulose in the G+0.693-0.027 Cloud
Researchers identified the presence of erythrulose using high-sensitivity radio telescopes, specifically the Yebes 40-meter dish and the IRAM 30-meter dish located in Spain. By analyzing the faint radio signals emitted as molecules spin, the scientists matched 12 spectral lines to known laboratory signatures of the sugar.
The discovery was unexpected because the cloud showed a relative absence of three-carbon sugars. While traditional astrochemistry models often assume interstellar molecules grow by adding one carbon atom at a time, the researchers propose that erythrulose likely formed through the combination of glycolaldehyde and ethylene glycol—two-carbon molecules already abundant in the region.
Interstellar Ice and the Origins of Life
The study, published in the journal Nature Astronomy, provides a new perspective on how life-essential molecules might arrive on planets. Scientists have long debated how Earth acquired its initial supply of sugars, as lab experiments suggest the conditions on the early planet were not conducive to their formation. The detection of erythrulose suggests that huge chemical factories
in space can manufacture these compounds on microscopic dust grains, which are then carried to planetary surfaces via comets or asteroids.
Researchers estimate that between 0.5 and 55 million tons of erythrulose may have been delivered to Earth between 4.1 and 3.8 billion years ago during the Late Heavy Bombardment.
The Laboratory Challenge of Identifying Cosmic Sugars
Identifying specific molecules in space is inherently difficult due to the “barcodelike” nature of spectral light, where hundreds of different molecules broadcast signals simultaneously. Sugars, in particular, present a unique hurdle because they are typically syrupy liquids that are difficult to vaporize for laboratory comparison.
To overcome this, the research team utilized a new technique that stabilizes sugar by mixing it with talcum powder. This creates a solid that can be vaporized with a laser to generate a diagnostic light pattern. This breakthrough is viewed by the scientific community as a significant step forward. 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,
noted study co-author Carlos Briones.
Future Implications for Astrochemistry
The findings have prompted immediate interest from experts in the field. Yoshihiro Furukawa of Tohoku University, who previously discovered sugars in the Bennu asteroid, noted that the study confirms the potential for interstellar delivery systems. Sugars formed in the interstellar medium can reach Earth and other planets via cometary dust … This supply may have helped facilitate the emergence of life, if planetary environments were able to build life from such molecules, although that process itself remains unclear,
Furukawa said.
The team is now moving into a follow-up phase, using the same spectroscopic techniques to search for even more complex sugars and assessing how these delicate molecules survive exposure to ultraviolet radiation in deep space. As the scientific community continues to analyze the chemical composition of the G+0.693-0.027 cloud, the focus remains on understanding whether these interstellar factories are a universal feature of galaxy formation.
Find more reporting in our Tech section.
Keep reading
