MILKY WAY — Astronomers detected the sugar erythrulose in a gas cloud near the center of the Milky Way. This is the first time erythrulose has been detected outside the solar system.

The detection occurred in the interstellar medium gas cloud G+0.693-0.027. Researchers used the Yebes 40-meter and IRAM 30-meter radio telescopes in Spain to collect data. Scientists identified the sugar by comparing telescope signals to laboratory samples, a method that relies on matching observed spectral lines with known molecular signatures generated in controlled settings.

The results were published in the journal Nature Astronomy. Erythrulose is one of the most complex sugars detected in space to date. It consists of four carbon atoms and is also found in raspberries and self-tanners. D-Erythrulose is a tetrose carbohydrate with the chemical formula C4H8O4 and belongs to the ketose family, featuring one ketone group.

Erythrulose is not essential for life but can convert to threose, a sugar believed to be a precursor to RNA and DNA. The findings suggest erythrulose can form from simpler molecules on dust grains in space. This supports the theory that essential ingredients for life were present in the early solar system rather than delivered later by comets or asteroids.

"We were able to achieve this detection thanks to the combination of exceptionally sensitive observations, extensive frequency coverage, and highly accurate laboratory spectroscopic data," said Izaskun Jiménez-Serra, staff researcher at the Spanish National Research Council. She added, "Sugars are important molecules in living systems, helping to provide energy, build important biological structures, and form parts of genetic material." Jiménez-Serra, an astrophysicist at the Center for Astrobiology in Spain, also noted, "The key ingredients for the origin of life could be present in other regions across the galaxy, opening the possibility for life to develop elsewhere in the universe."

"It's a pristine example of the stuff that's just floating out in the galaxy," said Erika Hamden, astrophysicist with the University of Arizona.

Why It Matters

The discovery expands the inventory of prebiotic molecules known to exist in interstellar space and strengthens hypotheses about the cosmic origins of life’s building blocks. Detecting increasingly complex organic compounds like erythrulose in star-forming regions suggests that chemical processes capable of assembling biologically relevant molecules operate widely across the galaxy, even in the absence of planetary systems.