Recently the ALMA observatory published their findings on 3I/ATLAS showing the presence of a rich concentration of CH₃OH (methanol) and HCN (hydrogen cyanide). Per the ALMA study, the interstellar interloper’s methanol-to-hydrogen cyanide ratio is second only to C/2016 R2 (PanSTARRS).
What exactly does this study indicate as speculations about the exocomet abound, with a significant segment of stargazers and laymen hoping 3I/ATLAS is more than a mere comet? Is it?
Breaking down the ALMA observation Harvard astrophysicist Avi Loeb in his latest blog remarked
The hydrogen-cyanide production was found to be depleted in the sunward direction, whereas methanol was enhanced in that direction. Some methanol was produced in the gas plume itself at distances beyond 258 kilometers from 3I/ATLAS.
He further elaborated on the biological significance of these molecules in terms of biosignature. He stated how Methanol, a building block of amino acids and sugars like ribose, is found in abundance in star-forming regions. He wrote
A diverse group of microorganisms, including bacteria and yeasts, known as methylotrophs, are able to use methanol as their sole source of energy. These organisms possess specialized enzymes, such as methanol dehydrogenase, to oxidize methanol to formaldehyde, which is then assimilated into biomass or used to produce valuable chemicals like amino acids. Methanol is naturally produced in plants, primarily from the breakdown of cell wall components like pectin. Gaseous methanol acts as a signaling molecule, inducing defense reactions in wounded plants and helping to regulate plant immunity against pathogens.
What about Hydrogen Cyanide, a poison that has been detected in Titan’s atmosphere as well? Loeb noted how the compound was used in World War I as a chemical weapon yet in itself is a precursor to organic production. Her remarked,
The chemical properties of hydrogen cyanide allow it to serve as a precursor for the formation of complex organic molecules, such as amino acids and nucleic acid bases like adenine. Some bacteria produce it as a secondary metabolite to inhibit the growth of competing microorganisms by disrupting their respiration. Hydrogen cyanide is naturally produced by many plants as a co-product of ethylene biosynthesis and in the breakdown of cyanogenic glycosides.
At low concentrations, hydrogen cyanide promotes seed germination and enhances resistance to stressors such as salt, cold or pathogens.
So is it an interstellar panspermia probe or a serial killer? Loeb argues
The anomalously large ratio of methanol to hydrogen-cyanide production by 3I/ATLAS suggests a friendly nature for this interstellar visitor.
📡We are on @MashableIndia “3I/ATLAS: ALMA Detects Most Enriched Concentration Of Methanol And Hydrogen Cyanide Observed In Any Comet Ever” https://t.co/LzfKMbidqG
— ALMA Observatory📡 (@almaobs) December 6, 2025
See Also: 3I/ATLAS: NASA & ESA Release Fresh Pictures Of The Interstellar Comet Triggering Memefest On X
See Also: 3I/ATLAS: Japan’s XRISM Probe Captures X-ray Emission From Exocomet Ahead Of Earth Flyby
Cover: Cyanide bottle