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Astronomers have detected the first true sugar molecule, called erythrulose, in interstellar space, marking a major step forward in understanding how the building blocks of life may form beyond Earth. The discovery was made in a giant molecular cloud named G+0.693−0.027, located near the center of the Milky Way galaxy, about 26,745 light-years from Earth.
Erythrulose, a four-carbon sugar also found in raspberries and some self-tanning products, was identified through ultra-sensitive radio telescope surveys by an international team led by Izaskun Jiménez-Serra of the Spanish National Research Council. Researchers used the Yebes 40-meter and IRAM 30-meter radio telescopes in Spain to analyze the molecular cloud’s chemistry. They matched 12 spectral lines in the cloud with the laboratory spectrum of erythrulose, confirming its presence in space for the first time.
Sugars are vital for life, acting as both energy sources and as parts of DNA and RNA. Their formation on early Earth remains a central question in origin-of-life research. While sugars like ribose and glucose have been found in meteorites, this is the first direct detection of a true sugar in the interstellar medium. The research team found that erythrulose is at least eight times more abundant than simpler three-carbon sugars, challenging previous theories that larger molecules form by adding one carbon atom at a time. Instead, the evidence suggests erythrulose formed from the combination of two-carbon molecules on the icy surfaces of dust grains in space as detailed by ScienceAlert.
The abundance of erythrulose in space leads scientists to believe that millions of tonnes of such sugars could have arrived on early Earth via comets or meteorites during the Late Heavy Bombardment period, roughly 4.1 to 3.8 billion years ago. This supports the idea that key ingredients for life may have come from outer space, offering new clues about how life began on our planet.
Researchers are now planning further studies to search for even more complex sugars, such as ribose, the sugar found in RNA. The finding opens the possibility that other important prebiotic molecules could form and survive under extreme conditions in interstellar space, bringing us one step closer to understanding life’s cosmic origins.