As NASA insists the newly released images of interstellar visitor 3I/ATLAS confirm it is nothing more than a comet, Harvard astrophysicist Avi Loeb is arguing the opposite, that the most intriguing clues are only now emerging, and that the real answers may not arrive until Christmas. In a new blog post, he challenges NASA’s certainty, pointing to puzzling structures captured in recent observations and warning that scientists “should not judge a book by its cover.”
NASA releases new images, and Loeb responds
When NASA finally released long-delayed images of the interstellar object 3I/ATLAS earlier this week, the agency framed the moment as reassuringly straightforward. The object, they said, is “a comet,” one that “does comet things”, sheds gas and dust, and poses “no threat to Earth”.Shortly after the release, Harvard astrophysicist Avi Loeb published a sharply worded rebuttal on his personal blogaccusing NASA of ‘repeating the official mantra’ and arguing that the newly released data leaves significant questions unanswered.” “I was not surprised. There was no big news,” he wrote after NASA’s briefing. “NASA repeated the official mantra that 3I/ATLAS is a natural comet and that they were unable to process the data until recently because of the government shutdown.” The new Mars-orbiter image, he noted, was little more than “a fuzzy ball of light”, blurred by spacecraft jitter. Loeb said he would be analysing the raw data “to extract the most important information out of it.”
The features Loeb says NASA underplays
Loeb says the newly released NASA image itself does little to resolve the mystery. The HiRISE camera aboard the Mars Reconnaissance Orbiter captured 3I/ATLAS on 3 October, but at a distance of roughly 30 million kilometres the result was, as he put it, simply “a fuzzy ball of light”. With a spatial resolution of 30 kilometres per pixel and visible spacecraft jitter, the light from the object “is smeared by several pixels”, revealing almost no structure at all.
A picture of 3I/ATLAS taken while it was 19 million miles away from Mars (NASA/JPL-Caltech/University of Arizona)
He argues that the real clues lie elsewhere. “The most interesting new insights about 3I/ATLAS were obtained in recent weeks,” he wrote, referring to amateur astronomers who photographed the object after its closest approach to the Sun on 29 October. These long-exposure images show two striking anomalies: first, perfectly straight, tightly collimated lines extending roughly a million kilometres on either side of the object, and second, the fact that these lines sit at right angles to the Sun–object axis, rather than pointing away from the Sun as natural comet jets do.“These images show tightly collimated jets pointing towards and away from the Sun and reaching distances of order a million kilometres,” he wrote. “In retrospect, these amateur astronomer images are far more exciting than the HiRISE image shared by NASA’s officials.”He says that if these features are genuine, and not artefacts or satellite streaks, they demand explanation. Natural jets should show wiggles from the object’s 16-hour rotation, not ruler-straight lines; and sunlight-driven dust should not be ejected sideways in this manner. He adds, pointedly:“Mother Nature was kinder to NASA than expected from a random delivery of rocks by at least a factor of 100,000 based on the two anomalies mentioned above.”
Why Loeb thinks conventional explanations are incomplete
NASA’s position, that the object is a natural comet, is broadly accepted by the astronomy community. But Loeb argues this interpretation assumes too much. Responding to NASA’s assertion that jets of gas and dust prove its cometary nature, Loeb writes: “A spacecraft that collected dust and CO₂, CO & H₂O ices on its surface by traveling through the cold interstellar medium could have also developed an outer layer of dust mixed with ices that sublimate when illuminated by sunlight. We should not ‘judge a book by its cover,’ because we all know about the Trojan Horse which appeared unthreatening to the guardians of the City of Troy.” He doubles down by invoking Sherlock Holmes: “There is nothing more deceptive than an obvious fact.” And: “It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.” Loeb argues that NASA is doing precisely what Holmes warned against, assuming explanations that fit past experience rather than following the anomalies.
The possibilities he thinks remain on the table
Loeb stresses he is not asserting that 3I/ATLAS is alien, but that, at this stage, both natural and technological possibilities remain viable. He outlines the fork plainly:
- A natural scenario: fragments of ice or rock breaking off as the interstellar body fractured near perihelion
- A technological scenario: “mini-probes released by a technological mothership”
He emphasises that he recently urged NASA to examine whether any small objects had travelled with 3I/ATLAS or peeled away towards Mars or Earth: “Related data from Mars rovers or orbiters or from Earth-based NASA satellites or Galileo Project observatories could reveal fragments from an iceberg that broke up or mini-probes released by a technological mothership.” One UK publication, LADbible, has previously quoted Loeb arguing that NASA acts as though it is “pretending to be the adults in the room,” and accused the agency of dismissing anomalies too readily, a point he echoes again in this week’s blog.
Why Loeb says Christmas is the crucial test
For Loeb, the coming weeks are decisive. He writes: “In the coming weeks, larger ground-based telescopes as well as the Hubble and Webb telescopes will be able to characterize the jets of 3I/ATLAS by measuring their composition, speed and mass loading rate.” These measurements, he says, will determine whether the jets come from “natural pockets of ice that are warmed by sunlight or by technological thrusters.” And he sets a firm timeline: “We should know the answer by the time 3I/ATLAS is closest to Earth on December 19, 2025, a gift of new interstellar knowledge for the holidays.” Loeb previously said that “by Christmas” we would have enough data to know whether the object is losing mass like a comet, or behaving in an unexpected way.
A scientist who relishes the unknown
Loeb ends his piece by making clear that he sees curiosity, not certainty, as the core of the scientific enterprise: “Life is worth living if we allow for the unexpected to surprise us. In particular, the known unknowns are great but the unknown unknowns are the best. Bureaucrats or unimaginative scientists want us to believe in the expected. But the rest of us know that the best is yet to come.” Whatever the coming observations reveal, the debate around 3I/ATLAS is unlikely to quieten. As the head of the Galileo Project and Harvard’s former astronomy chair, Loeb has long been the most public advocate for taking interstellar anomalies seriously. The next few weeks, he argues, will show whether this object is simply another icy wanderer, or something unlike anything humanity has yet encountered.
