On July 1, 2025, initial detection of the space object now known as 3I/ATLAS was first reported, marking the third confirmed interstellar object ever discovered within our solar system.
Since its discovery, 3I/ATLAS has sparked debate among astronomers, with most concluding that all available evidence suggests it is a comet.
However, a more controversial theory has explored the unlikely possibility that this massive interstellar object could be something more unusual than the standard comet.
Harvard astronomer and theoretical physicist Avi Loeb is well known for his investigations involving ‘Oumuamua, the first confirmed interstellar object spotted within our solar system back in October of 2017. At that time, Loeb and some of his colleagues argued that ‘Oumuamua displayed several unusual qualities, which led them to consider a bold possibility: that the object might potentially have technological origins.
According to Loeb, 3I/ATLAS, as well as its predecessor ‘Oumuamua discovered in 2017, and the interstellar “rogue” comet 2I/Borisov discovered in 2019, displayed unusual trajectories that follow a highly eccentric path, which appears to indicate they were not gravitationally bound to the Sun.
In a post on his Medium page on July 4, 2025, Loeb wrote that 3I/ATLAS may be one of two things: a comet possessing a smaller core with a radius less than 400 meters, or “an object that favored a radial orbit into the inner solar system” meaning that it may also be a larger object compared to its predecessors. Indeed, further observations of the object eventually suggested that 3I/ATLAS appears to be significantly larger than ‘Omuamua or Borisov was.
The object’s larger size and current estimated trajectory, according to Loeb in a recent podcast interview, suggest the possibility that it may not have been traveling on a random path, but rather that its current movement can be interpreted as having been “aimed” at the inner solar system.
“That obviously opens the door for it being technological, because who would target the inner solar system?” Loeb mused during the interview.
Loeb subsequently authored a paper on the mysterious interstellar object and said that although it was accepted for publication, the editor made a specific request.
“It was accepted by the editor under one condition: that I remove any reference to a possible technological origin,” Loeb said.
Recent photos of the interstellar object 3I/ATLAS obtained by the Hubble Space Telescope reveal features that are atypical when it comes to the normal appearance of comets. Typical comets develop a tail as sunlight pushes dust and gas away from the nucleus, trailing in the opposite direction of their motion. However, Hubble imagery shows dust emitted from the Sun-facing side and a faint tail pointing away from the Sun, consistent with dayside sublimation; some images emphasize a bright, slightly forward-biased coma.
Loeb likens this to spotting a “zebra without stripes,” arguing that such a sun-facing emission with a weak tail away from the Sun is an unusual feature.
“If you see an animal that doesn’t have stripes, you can’t say it’s a zebra, because that is the defining characteristic,” Loeb said, adding that its “remarkable” trajectory makes the object even more unusual.
New Perspectives on 3I/ATLAS
In early August, the publication of a pair of new papers offered additional data on 3I/ATLAS. One of these, a study based on data obtained with the SOAR Telescope in Chile, examined the object’s light spectrum, taken when it was 4.4 astronomical units from the Sun. The reflected light appeared reddened, yet no gas signatures from typical cometary molecules—such as CN, C3, C2, CO+, or neutral oxygen—were detected. The authors called this a “paradoxical situation of early onset coma without evidence of sublimation tracers,” which, they said, “calls for other dust-liberating mechanisms that ancient interstellar objects may be subjected to.”
The second paper, by David Jewitt and his colleagues, analyzed Hubble’s first images of 3I/ATLAS, concluding it is indeed a comet with a small nucleus—between 0.32 and 5.6 kilometers wide—surrounded by a substantial dust cloud.
Loeb recently wrote in an update at his Medium blog that the Hubble image reveals diffuse emission ahead of the object’s motion towards the Sun, rather than a trailing tail as expected from a typical comet. Loeb argues that a forward glow could be explained if the nucleus does not spin rapidly, adding that if “the object’s surface is exposed to the Sun, it would maintain a hot dayside from which most of the evaporation of dust takes place.
“This explanation is indeed adopted in the new paper,” Loeb said of Jewitt and the team’s study.
However, Loeb has also argued that the timing of 3I/ATLAS’s closest approach to the sun may be significant.
“It arrives closest to the sun when the Earth is on the opposite side, so we can’t observe it,” Loeb said during the recent podcast interview. This is crucial, he says, because “coming closest to the sun is the point in time when it can do a maneuver,” or in other words, gaining a velocity boost from the sun’s gravity similar to how Earth spacecraft achieve gravity assists during space missions.
By the admission of its own authors, a paper by Loeb and two colleagues uploaded to the preprint arXiv.org server last month referred to the idea of 3I/ATLAS potentially being extraterrestrial technology as a “testable hypothesis, to which the authors do not necessarily ascribe,” further characterizing the paper as “largely a pedagogical” exercise.
Naturally, many experts have pushed back on any characterizations of 3I/ATLAS as being potential evidence of extraterrestrial technology. Michigan State University astronomer Darryl Seligman, one of the first scientists to publish a paper on the object, told Live Science last month that the growing body of telescopic observations currently demonstrates “that it’s displaying classical signatures of cometary activity.”
Samantha Lawler, an astronomer at the University of Regina in Canada, expressed similar sentiments, saying that all the current evidence suggests 3I/ATLAS is simply a comet that escaped from another solar system, just like “countless billions of comets have been ejected from our own solar system.”
For now, 3I/ATLAS remains an enigma, even if it is simply a comet from afar that made its way into our solar system. Astronomers expect to resume observations later this year, which could help clarify whether the object’s behavior is simply an oddity of natural physics or, as Loeb and his colleagues have explored, something that potentially expands our understanding of the behavior of interstellar objects that come close enough to be viewed from Earth.
The recent paper, “Is the Interstellar Object 3I/ATLAS Alien Technology?” by Avi Loeb, Adam Hibberd, and Adam Crowl, appeared on the preprint arXiv.org website on July 16, 2025.
Chrissy Newton is a PR professional and founder of VOCAB Communications. She currently appears on The Discovery Channel and Max and hosts the Rebelliously Curious podcast, which can be found on YouTube and on all audio podcast streaming platforms. Follow her on X: @ChrissyNewton, Instagram: @BeingChrissyNewton, and chrissynewton.com.