Astronomers Stunned To Discover A Comet Loaded With Alcohol

Comet 3I/ATLAS has once again found its way into headlines as astronomers are astounded to learn the famous space rock is emitting large amounts of organic methanol in its coma. The group of astronomers used the Atacama Large Millimeter Array, also known as ALMA, to make the discovery.

Late last year astronomers and other scientists debated whether Comet 3I/ATLAS was a natural swan comet from another star system or possibly a piece of alien technology. While that debate remains unsettled, new findings indicate the comet is second only to C/2016 R2 in terms of methanol levels ever recorded in a comet within our solar system.

"Observing 3I/ATLAS is like taking a fingerprint from another solar system," noted Nathan Roth, lead author on the research, and a professor with American University. Roth continued, "The details reveal what it’s made of, and it’s bursting with methanol in a way we just don’t usually see in comets in our own solar system."


The data was collected by ALMA, during the months of August, September, and October of 2025. The team’s focus was on two submillimeter fingerprints: methanol, a type of alcohol, and hydrogen cyanide (HCN), an organic molecule often seen in other comets. What surprised the astronomers was the fact that the levels of methanol were far greater than those of hydrogen cyanide. On two separate occasions the team measured the methanol-to-HCN ratios to be between about 70:1 and 120:1. The team stated in its research that these levels “are among the most enriched values measured in any comet, surpassed only by anomalous solar system comet C/2016 R2 (PanSTARRS).”

Before ALMA made its observations of the comet as it passed by the Sun, the James Webb Space Telescope was used to spy on the interstellar traveler while it was far from the Milky Way’s star. During those observations, Webb showed Comet 3I/ATLAS’ coma was made up of mostly carbon dioxide. ALMA’s imaging enabled the team to view how the different molecules moved away from the comet. It appeared to show the hydrogen cyanide being emitted first, coming from the comet’s nucleus, or core. The methanol, however, appeared to be coming from both the core and from ice particles in the coma. While seeing methanol coming from ice particles is similar to other solar system comets observed, it is the first time it has been documented in an interstellar object.

As Comet 3I/ATLAS now makes its way back out of our solar system, the new data gleaned from its passage will continue to shed new light on what is out there.

Top Image Credit: NSF/AUI/NSF NRAO/M.Weiss