Astronomers have reported the first detection of a true sugar molecule in interstellar space, a result that adds another awkwardly biological-sounding compound to the inventory of chemistry happening far from planets.
The molecule is erythrulose, a four-carbon ketose sugar found on Earth in some fruits and used in tanning lotions. In a study published this week in Nature Astronomy, a team led by Izaskun Jiménez Serra said it identified erythrulose in the molecular cloud G+0.693−0.027, about 26,000 light-years away near the Milky Way’s center.
The finding matters because sugars are part of the chemistry of life as we know it. Cells use sugars for energy, and ribose is a structural component of RNA. The old unresolved problem is how enough of these molecules, or their precursors, became available on early Earth. One candidate delivery mechanism is meteorites carrying prebiotic material made elsewhere.
That hypothesis gets a little more chemical plumbing with this detection. It does not show that life exists in space, or that Earth’s life started because sugar rained down from the sky. It shows that at least one monosaccharide can form or persist in the interstellar medium, which is the gas-and-dust material between stars. That is a narrower claim, and a more useful one.
How the team found it
Jiménez Serra’s team used observations from two Spanish radio facilities: the Yebes Observatory northeast of Madrid and the Institute for Radio Astronomy in the Millimeter Range facility in the Sierra Nevada mountains. The researchers looked for the microwave fingerprints produced as molecules rotate. Different molecules emit or absorb at characteristic frequencies, which is less romantic than “sugar in space” and much closer to the actual work.
The target, G+0.693−0.027, was chosen because it is chemically busy. The cloud sits near the supermassive black hole at the center of the galaxy, and collisions with another cloud appear to have driven chemical activity there. Researchers had previously identified alcohols, aldehydes, urea, ethanolamine, hydroxylamine and many other complex organic molecules in the region.
Jesús R. Flores, a professor at the University of Vigo who was not involved in the work, told Science Media Center Spain that prebiotic organic molecules, including some monosaccharides, are already known from meteorites and asteroids, but their origin remains unclear. One plausible explanation, he said, is formation in the interstellar medium. Until this report, Flores said, no true saccharide had been detected there.
What it does and does not mean
The result follows other evidence that space rocks can contain biologically relevant chemistry. In December 2025, scientists confirmed that samples from the asteroid Bennu contained ribose and other monosaccharides. Ribose is central to RNA, while erythrulose belongs to a different sugar family and is not itself described as essential for life.
The Nature Astronomy study nevertheless gives researchers another data point in the slow cataloging of prebiotic chemistry beyond Earth. The useful conclusion is modest: compounds associated with life’s chemical toolkit can be made outside living systems and outside planets. The annoying but necessary caveat is that a molecule with a familiar name is not a biosignature.
Erythrulose may be convertible into building blocks that matter more directly for prebiotic chemistry, according to the study summary. For now, the detection makes the Milky Way’s central molecular clouds look a bit more like a messy chemistry lab and a bit less like empty scenery.
This story draws on original reporting from WIRED.
