Interstellar Comet 3I/ATLAS is exceptionally alcoholic

Interstellar Comet 3I/ATLAS is exceptionally alcoholic

By Jackie Flynn Mogensen edited by Claire Cameron

Interstellar Comet 3I/ATLAS is the gift that keeps on giving. A snapshot of space beyond the solar system, it holds clues to other stars, other worlds, and the galaxy we call home. Only three such interstellar objects have ever been discovered, and by studying each of them we learn more about what’s beyond our cosmic neighborhood.

Last year, the comet was on its way to pass our Sun, reaching speeds of more than 150,000 miles per hour at its closest point. That orbit gave scientists an opportunity to observe the comet in detail, revealing that it is unusually alcoholic.

“Observing 3I/ATLAS is like taking a fingerprint from another solar system,” Nathan Roth, research assistant professor at American University, said in a statement. “The details reveal what it’s made of, and it’s full of methanol in a way we don’t usually see in comets in our own solar system.”

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As a typical comet approaches the Sun, ice inside the space rock turns to gas, leaving a trail of gases like carbon monoxide, methane, and ammonia in its wake—and sometimes a little methanol. But according to new measurements from the ground-based Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, the interstellar interloper is “heavily enriched” in methanol—in fact, far, far more methanol than astronomers would have expected.

The discovery could provide clues to where 3I/ATLAS came from: a question that has intrigued scientists since the comet’s discovery in July 2025. The research has been posted on the preprint server arXiv.org and is yet to be peer-reviewed.

Meanwhile, Comet 3I/ATLAS is still going strong on its journey through our solar system – and our spacecraft is still keeping an eye on it. In February, a new image taken by the European Space Agency’s Jupiter Icy Moons Explorer spacecraft revealed that 3I/ATLAS, now past the sun, appeared as a “white, glowing egg-shaped object” as it passed, according to the agency.

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