Scientists have discovered an abundance of molecules in the cosmos, but for the first time ever, they were able to detect one in interstellar space very familiar to us here on Earth: sugar.
The discovery, made in the vast clouds of gas and dust between stars, could help scientists better understand how some of the chemical ingredients necessary for life formed long before Earth existed.
Researchers at the Centro de Astrobiología, part of the Spanish National Research Council (CSIC), identified the sugar molecule erythrulose within the interstellar medium.
Sugars are considered fundamental building blocks of life. On Earth, they play vital biological roles, including forming the backbone of RNA and contributing to the chemistry that ultimately supports DNA, while also serving as an important source of energy. Scientists studying the origins of life have long sought to understand how the first sugars formed, since they are essential ingredients in the molecules associated with life’s earliest development.
“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,” says Carlos Briones, co-author of the study, in a statement.
Even so, one major question remains: where did the first biologically important sugars originate?
Previous studies have identified sugars such as ribose and glucose in meteorites and asteroid samples, suggesting that some organic compounds may have been delivered to the early Earth from space. Until now, however, no sugar had been directly detected in the cold molecular clouds where stars and planets form.
The newly identified molecule, erythrulose, was found in the molecular cloud G+0.693−0.027 near the center of the Milky Way. On Earth, erythrulose is a naturally occurring four-carbon ketose sugar.
The discovery was made using highly sensitive radio astronomy observations from the Yebes Observatory’s 40-meter radio telescope and the 30-meter telescope operated by the Institute for Radio Astronomy in the Millimeter Range. Researchers analyzed the unique radio signatures, or spectral fingerprints, emitted by molecules in space.
The team identified 12 spectral lines matching laboratory measurements of erythrulose, confirming the molecule’s presence.
The findings also challenge some existing ideas about how complex molecules form in space. Scientists have generally proposed that interstellar chemistry builds larger molecules by gradually adding carbon atoms. Yet erythrulose proved to be more abundant than related three-carbon sugars that researchers expected would appear first.
“This finding was unexpected, as the prevailing view in astrochemistry is that interstellar molecules grow in size through the sequential addition of carbon atoms,” said Izaskun Jimenez Serra (CAB), the lead author of the recent study.
Instead, the researchers found that erythrulose could form inside icy dust grains from simpler two-carbon alcohols and aldehydes. These frozen environments may function as natural chemical laboratories, allowing increasingly complex organic molecules to develop over time.
The team estimates that during the Late Heavy Bombardment—roughly 4.1 to 3.8 billion years ago, when Earth experienced intense asteroid and comet impacts—between 500,000 and 50 million tonnes of erythrulose may have been delivered to the planet’s surface.
The discovery adds another piece to the puzzle of life’s origins, suggesting that some of its essential ingredients may have arrived with something surprisingly sweet.
This paper was published in the journal Nature Astronomy.
Chrissy Newton is a PR professional and the founder of VOCAB Communications. She currently appears on The Discovery Channel and Max and hosts the Rebelliously Curious podcast, which can be found on YouTube and on all audio podcast streaming platforms. Follow her on X: @ChrissyNewton, Instagram: @BeingChrissyNewton, and chrissynewton.com. To contact Chrissy with a story, please email chrissy @ thedebrief.org.