Astronomers have detected a simple sugar—normally found in raspberries and fake tan lotions—drifting in a massive dust and gas cloud near the center of the Milky Way. The discovery marks the first time sugar has been directly spotted in interstellar space, showing that the chemical building blocks of life can form in the freezing depths of the universe.
The compound, a four-carbon sugar called erythrulose, was identified by researchers using two radio telescopes in Spain to observe a cold dust cloud known as G+0.693-0.027. While scientists had previously found sugars inside ancient meteorites and on the Bennu asteroid, they had never before observed them directly in the vast interstellar medium between stars.
According to the study published in Nature Astronomy, erythrulose likely forms when two other organic compounds, glycolaldehyde and ethylene glycol, combine on the surfaces of microscopic dust grains. Remarkably, these chemical reactions occur despite temperatures hovering around a freezing -250°C.
"This is the very first sugar to be detected in interstellar space, and it is important because it tells us that these sugars are more common than we previously thought," said Dr. Izaskun Jiménez-Serra of Spain’s Centre for Astrobiology. She explained that the discovery opens up the possibility that life could develop on other worlds in a similar way to how it began on Earth.
Simple sugars like erythrulose are crucial because they can react to form ribonucleotides, which are the building blocks of RNA. Scientists believe RNA was probably the first genetic material for early life on Earth before DNA evolved. The research team estimates that millions of tons of this sugar could have rained down on the young Earth during the Late Heavy Bombardment, a period when the planet was battered by a surge of asteroids and comets. This organic rain may have enriched the prebiotic soup from which the first living organisms eventually emerged.
While erythrulose is known to react with dead skin cells in self-tanners to create a bronzed effect, its discovery in the freezing depths of space serves a far more profound purpose: demonstrating that the universe is capable of producing complex organic chemistry in the most inhospitable environments.