Scientists Found Sugar in Space. It Could Rewrite the Origin of Life.

3 min readHere’s what you’ll learn when you read this story:Life requires a few ingredients to get going, including sugars that form the backbone of DNA and RNA. A new study found a four-carbon sugar named “erythrulose” in a molecular cloud in the interstellar medium (ISM) roughly 26,000 light-years away. It’s possible that early meteorites brought billions of kilograms of erythrulose to Earth during the Late Heavy Bombardment.Like any good recipe, life also relies on a few key ingredients. Hydrogen, check. Oxygen, check. Carbon, nitrogen, sulfur? Check check check. But another of these components remains something of a mystery, since it’s central to the formation of living organisms, but scientists don’t yet know how it arose on Earth.Sugar forms the structural backbone of DNA and RNA, so it must have been on Earth early on. The prevailing theory is that sugar arrived on the backs of comets that pummeled the Earth nonstop during its fiery youth. This hypothesis gained a major victory in 2023 when scientists discovered that Bennu, the asteroid target for NASA’s soil return mission known as OSIRIS-REx, contained essential sugars necessary for life. Now, a new study published in the journal Nature Astronomy details scientists’ interstellar discovery of traces of a different, yet essential, sugar called erythrulose (C4H8O4).Found most commonly in raspberries on Earth, scientists found the organic compound in space in the thin gas clouds that make up the interstellar medium (ISM). “A central question in origin-of-life research is how monosaccharides formed on the primitive Earth, as laboratory experiments under prebiotic conditions yield insufficient concentrations,” the authors write. “The discovery of interstellar erythrulose suggests that the ISM could be a viable source of sugar feedstock for the prebiotic synthesis of the first nucleic acids, not only on the primitive Earth but also elsewhere in the Universe.”To make this surprising discovery, the team trained two radio telescopes—the Yebes Observatory and the Institute for Radio Astronomy in the Millimetre Range’s (IRAM) 30-meter telescope, both in Spain—at a molecular cloud G+0.693−0.027 more than 26,000 light-years from Earth. Located within the Sagittarius B2 complex, a large molecular cloud complex only 390 light-years from the center of the Milky Way, G+0.693 is “one of the richest molecular reservoirs known in the Galaxy,” according to the authors.Chemical & Engineering News reports that G+0.693 contains molecular species that form on icy dust grains and release as gas molecules. Because of the cloud’s low temperature, these molecules emit radio waves and certain frequencies that scientists can identify. So far, scientists have detected some 340 types of molecules in G+0.693.But the newly discovered sugar molecule is important—and strange—in a couple ways. Sugar has never been directly observed in the interstellar medium and, perplexingly, the scientists found a complex four-carbon sugar rather than a simpler three-carbon one.“We’ve never managed to detect a sugar [outside of our solar system],” MIT’s Brett McGuire tells Chemical & Engineering News. “And now we skipped all the three-carbon sugars and went straight to four carbons. That’s astonishing.”By analyzing the average amount of water content in meteorites along with how much material was delivered to early Earth, the research team estimates that anywhere from 0.5 to 50 billion kilograms of erythrulose could have arrived on the planet during the Late Heavy Bombardment, around four billion years ago. This introduction of sugar on ancient Earth may have helped kickstart life in our Solar System, but the study’s lead author—the Center for Astrobiology in Spain’s Izaskun Jiménez-Serra—says the implications could stretch far beyond just our home planet.“The key ingredients for the origin of life could be present in other regions across the galaxy,” Jiménez-Serra told the Associated Press, “opening the possibility for life to develop elsewhere in the universe.”Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.