Astronomers have detected erythrulose, a four-carbon sugar molecule, within the G+0.693−0.027 molecular cloud located 26,000 light-years from Earth. Published in Nature Astronomy this week, the discovery demonstrates that monosaccharides can be synthesized in interstellar environments, and the researchers emphasize that the existence of these molecules could help explain how the basic chemical ingredients of life might have arrived on Earth.
This is a significant step in the study of how the basic chemical ingredients of life could have emerged on our planet. For years, the origin of life’s building blocks—the chemicals involved in prebiotic chemistry—has been studied, and the detection of erythrulose provides direct evidence that sugars can form in interstellar environments.
It’s a chemical puzzle. The ingredients are being formed in the interstellar medium.
The Spectroscopic Fingerprint of G+0.693−0.027
The research, led by Izaskun Jiménez Serra, analyzed data from two radio telescopes. The team utilized two specific instruments: the Yebes Observatory northeast of Madrid and the Millimeter-Range Radio Astronomy Institute near the Sierra Nevada mountains. By analyzing microwave frequencies, they identified the specific rotational “fingerprint” of erythrulose.
Why this specific cloud? G+0.693−0.027 is one of the regions richest in molecules in the entire Milky Way. Its proximity to the supermassive black hole at the center of the galaxy and collisions with other clouds have turned this area into a chemical factory. These conditions create an environment for chemical reactions to produce increasingly complex molecules.
The variety of organic compounds already logged in this region is noted. Before this, astronomers had already confirmed the presence of:
- Alcohol, aldehydes, and urea
- Ethanolamine and hydroxylamine
Adding sugar to this list shows that the interstellar medium is richer chemically than previously imagined.
From Asteroid Bennu to the Galactic Center
To understand the weight of this discovery, we look back at December 2025. That was when scientists confirmed that asteroid Bennu contained ribose and other monosaccharides. Ribose is a fundamental sugar in RNA. The Bennu discovery proved that our own solar system holds the chemical ingredients necessary for life.
The study demonstrates, for the first time, that interstellar monosaccharides can be synthesized. Erythrulose, while not essential for life, is a four-carbon ketomonosaccharide found naturally in raspberries and used in tanning lotions. It serves as a proof of concept that sugars can form in the interstellar medium.
“The existence of various prebiotic organic molecules in meteorites and asteroids is well known, including some monosaccharides, but their origin is still unclear,” says Jesús R. Flores, a professor at the University of Vigo. According to Flores, while the possibility of interstellar origin was always there, this is the first time a true saccharide has been detected there.
The Chemical Pipeline: Space to Soil
The researchers emphasize that the presence of sugar does not automatically prove the existence of extraterrestrial life, nor does it directly explain the origin of life on Earth or RNA. Instead, we are mapping the supply chain of the universe. Erythrulose can be converted into building blocks that might be necessary, and chain reactions in space could produce more complex molecules than previously thought.
The data suggests a process where meteorites and comets bring these molecules to Earth, providing raw materials that eventually trigger the emergence of life.
The Horizon: Searching for Complex Saccharides
The discovery of a four-carbon sugar is a milestone in astrobiology. The next objective is to search for more complex sugar molecules in the same region. If monosaccharides like erythrulose can form there, it is possible that larger sugar molecules relevant to life also exist.
For those tracking the intersection of astrophysics and biochemistry, the takeaway is that the building blocks of life can be found in outer space. The building blocks are forged in extreme environments, such as near supermassive black holes, and the findings have major implications for our understanding of how planets like Earth could obtain the chemicals necessary for life.
