Cloud Near Milky Way Center Hides Over 120 Molecules
In the G+0.633-0.0604 cloud near the Milky Way's center, astronomers have found over 120 molecules, including rare prebiotic compounds and all six biogenic elements.
Astronomers have catalogued over 120 different molecular species in the molecular cloud G+0.633-0.0604, located on the southern edge of the Sagittarius B2 complex near the very center of the Milky Way. The result was published on September 2, 2026, in research led by David San Andres of the Center for Astrobiology in Spain, with co-authors V. M. Rivilla, L. Colzi, M. Sanz Novo, S. Martin, I. Jimenez-Serra and S. Zeng, from institutions in Spain, Germany, Chile and Japan. The inventory includes all six so-called biogenic elements, carbon, hydrogen, oxygen, nitrogen, phosphorus and sulfur, placing the cloud among the chemically richest known sources in the galaxy.
Why This Cloud Changes the Picture of the Galactic Center’s Chemistry
The discovery carries extra weight next to the previously known cloud G+0.693-0.027, located just 32 light-years from the newly identified G+0.633 and itself home to roughly 40 percent of all molecules ever detected in interstellar space. Until now, G+0.693 was considered a singular case, a place where this kind of chemical diversity emerges from a rare combination of circumstances. According to the new paper, G+0.633 is the first confirmed chemical twin of that cloud, described in the study itself as “a new gold mine for astrochemistry.” That suggests the conditions that allow for such molecular richness are not an exception, but recur wherever the right physical circumstances come together.
The measurements were taken with the IRAM 30-meter telescope, an instrument mounted atop Pico Veleta in Spain. The new cloud has a practical advantage, the authors note: its spectral lines are half as wide as those of G+0.693, making it easier to separate and identify individual molecules in the recorded spectrum. The paper first appeared on the arXiv preprint server on August 14, 2026, with a revised version following on August 18, catalogued as 2608.14381. It was prepared for the proceedings of an International Astronomical Union symposium on the galactic center, meaning it is currently circulating as a preprint and has not yet gone through peer review at a scientific journal.
Among the identified compounds, three stand out for their direct ties to the chemistry of life. Ethanolamine, a building block of cell membranes that separate the inside of a living cell from its surroundings, has only been spotted in space once before. The same goes for sp-glycolamide, a structural relative of glycine, the simplest amino acid organisms use to build proteins. All three variants of cyanomethanimine were also found, compounds considered building blocks of adenine, one of the four genetic letters in RNA and DNA. The inventory also turned up benzonitrile, a molecule with an aromatic ring, whose presence further confirms the complexity of the chemistry in this part of the galaxy.
David San Andres and his co-authors wrote in the paper posted to arXiv: “This research uncovered over 120 molecular species containing all six essential biogenic elements.”
Does This Mean Life Has Been Found, or Something Close to It?
No. The presence of prebiotic molecules in an interstellar cloud shows that the chemical prerequisites for life can form under conditions far removed from any planet, but it does not prove that the same chemistry gave rise to life on Earth, nor that such chemistry leads to living organisms. The link between these molecules and the origin of life is, according to the paper itself, an indication, not proof of a causal relationship. The paper is a preprint and a version prepared for conference proceedings, so some findings may still be refined before final publication in a peer-reviewed journal.
The nature of the observation itself is also a limitation. Radio spectroscopy reveals the presence of molecules in the gas phase of the cloud, but it says nothing directly about what happens inside the ice on dust grains, where most researchers in the field believe the bulk of the observed molecular diversity forms before a shock wave releases it into the gas. Confirming that picture will require additional observations and, as is standard practice, independent replication of the findings with other instruments.
