Astronomers have found a complex sugar drifting in the thin clouds of gas and dust between the stars — the interstellar medium — and the discovery, published Monday in the journal Nature Astronomy, gives the chemistry of life’s beginnings a small new data point. The sugar goes by the name erythrulose, and it is familiar closer to home: the same molecule turns up in raspberries and in self-tanning lotions.
The detection came out of teamwork between two dish-shaped radio telescopes in Spain, which studied a large gas cloud parked near the middle of the Milky Way. Researchers identified the sugar in its gas form by matching the telescopes’ signals against samples measured in the laboratory — the standard discipline that separates a genuine find from wishful noise.
Why the fuss over a sugar? These molecules power our cells, and some of them help build DNA, which is why scientists keep asking how they form: sugars look to be a core ingredient of life as anybody understands it. Erythrulose itself is not essential for life, the researchers note, but it converts easily into a related form that researchers consider crucial for getting life started on Earth. It is also among the most complex sugars spotted in space so far, said Erika Hamden, an astrophysicist at the University of Arizona who was not involved in the study — “a pristine example of the stuff that’s just floating out in the galaxy,”
The find has a lineage. Scientists spotted a cousin of table sugar near the Milky Way’s center about 25 years ago, and black grains that NASA’s Osiris-Rex spacecraft gathered from the asteroid Bennu later gave up other sugars, one of them a key ingredient of DNA. The new detection came from a region of space crossed by NASA’s twin Voyager probes, the farthest spacecraft ever to travel from Earth.
The deeper argument is about origins. Did faraway comets or space rocks deliver life’s essential ingredients to Earth, or were those components already here, eventually giving rise to the solar system? The new sugar, the researchers say, lends evidence to the second theory — the building blocks were in place before the delivery van ever left. Izaskun Jiménez-Serra, an author of the study at Spain’s Center for Astrobiology, puts the implication generously: “The key ingredients for the origin of life could be present in other regions across the galaxy, opening the possibility for life to develop elsewhere in the universe,”
Early findings suggest, rather than prove, all of this — one sugar in one cloud is a hint, not a census. That is exactly why the next step is more of the same: researchers want to hunt for additional sugars in space and work out how they convert between forms. Finding this molecule in one spot makes it likely, by their reasoning, that other sugars wait in far corners of the galaxy, together with the rest of life’s shopping list — a careful, patient search that has just picked up a very sweet clue.
