The "drunken" comet surprises scientists again: all the anomalies of 3I/Atlas

It crosses our Solar System “sweating” alcohol at dizzying rates. This is not science fiction, but the surprising reality of 3I/ATLAS, the third interstellar object ever confirmed, identified after the famous 'Oumuamua and Borisov.

Discovered on July 1, 2025 and passing at the closest distance to Earth on December 19 of the same year, this celestial body coming from another stellar system is baffling astronomers around the world. The powerful antennas of the ALMA radio telescope, in the Chilean Atacama desert, have revealed an unexpected secret: 3I/ATLAS is a literally “drunken” comet.

Measurements show a coma saturated with methanol, with abundances up to four times higher than the “norm” of our home comets. With a fraction of methanol of about 8% of the total vapor, this interstellar traveler ranks second overall among the most alcohol-rich celestial bodies ever analyzed, surpassed only by the peculiar C/2016 R2 (PanSTARRS).

Interferometric maps also indicate that methanol and hydrogen cyanide (HCN) are expelled according to differing geometries: a hint of non-uniform sources in the nucleus, or secondary reactions induced by sunlight directly within the coma.

The anomaly of 3I/ATLAS does not end with alcohol. Unlike the comets of the inner Solar System, where water (H₂O) predominates, the coma of this object is heavily governed by carbon dioxide (CO₂). Since CO₂ is much more volatile than H₂O, it has allowed the comet to “ignite” and trigger outgassing activity even at great distances from the Sun, suggesting an unusually thin or fractured dust mantle.

To this picture is added an unexpected composition: production rates of iron and nickel in line with those typical of our comets, but associated with particularly intense and unusual signals of nitrogen-containing species. These elements provide an unprecedented glimpse into the origins of the galactic wanderer.

The observed chemical mixture indicates that 3I/ATLAS most likely formed in a remote and cold region of the original protoplanetary disk, where extreme temperatures favored the accumulation of ice and the synthesis of methanol.

The real twist, however, concerns the questions about the origins of life. Methanol is not life itself, but it constitutes an essential piece of prebiotic chemistry, a bridge towards the construction of increasingly complex organic molecules. The discovery of such an abundance of methanol in an alien comet suggests a disruptive reality: the chemical foundations of life are not exclusive to our Solar System. 3I/ATLAS is proving to be a genuine extraterrestrial “time capsule”, a natural sample of invaluable worth for understanding how the building blocks of life can form in distant worlds.