Paper Roundup July 2025: 3I/ATLAS "fanfiction," arsenic life retraction, K2-18b

Every month, I collect interesting, fun, rage-inducing, or otherwise noteworthy papers in complexity, astrobiology, and origins. Inclusion is not endorsement. Weird suggestions, glaring omissions, and typos are 100% human error and 0% AI hallucination. Think something should be included in next month's newsletter? Shoot me an email at elise@reviewertoo.com.

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Highlights

Astrobiology: "Comet fanfiction about aliens"

Is the Interstellar Object 3I/ATLAS Alien Technology? (July 22, arXiv preprint) by Adam Hibberd, Adam Crowl, and Abraham Loeb

For the third time, astronomers have spotted a visitor from beyond the solar system: interstellar comet 3I/ATLAS. Avi Loeb, a Harvard astrophysicist- turned-alien-hunter who thinks we should be devoting more energy and funding to searching for intelligent life than exoplanet biosignatures. Loeb has a bad reputation for making sensational claims and behaving unprofessionally with colleagues who disagree with him; he's effectively been ostracized from the astro community at this point. He also has a history of thinking objects like this might be interstellar alien spacecraft. So the jokes started flying basically as soon as 3I/ATLAS was announced, and only intensified after Loeb did indeed suggest that the interstellar interloper could be a spaceship in comments for a predictably sensational story in the British tabloid Daily Mail.

As of tonight's Arxiv I don't believe my colleague on the 2nd floor has yet published a claim that it's a spaceship.

— Jonathan McDowell (@planet4589.bsky.social) July 3, 2025 at 3:19 AM