With the recent discovery of the mysterious space object 3I/ATLAS, the third-known interstellar object directly observed by astronomers, debate over its origins—and even the possibility that it might be of technological origin—has captured the public imagination.
Now, an international team of astronomers suggests that the rare appearances of interstellar objects passing through our solar system could provide scientists with an opportunity to search for signs of extraterrestrial technology.
While the available evidence strongly supports the view that 3I/ATLAS is a comet, albeit one bearing some rather unusual qualities, the team behind the recent study nonetheless suggests that there are good reasons to consider interstellar objects passing through our solar system as potential candidates in the search for alien technosignatures.
3I/ATLAS: A Comet, or Alien Technology?
Following the discovery of 3I/ATLAS on July 1, 2025, speculations about the object’s nature and origin have entertained a range of possibilities based on some of its unusual characteristics. Among these is the idea proposed by Harvard astronomer Avi Loeb and colleagues in a preprint paper earlier this year, which examined whether the object’s trajectory and non-gravitational motion through the solar system might suggest that it bears the qualities astronomers could expect from an intelligently controlled spacecraft.
Notably, Loeb and his co-authors stated in the paper that their examination of the potentially technological origins of 3I/ATLAS had been largely pedagogical, although they maintained that such views should not be dismissed outright, even if the likeliest interpretation by far remains that the object is an interstellar comet.
Now, in a new study by an international team of scientists that reviews decades of speculation and outlines concrete strategies for examining interstellar comets and asteroids, the paper’s authors similarly argue that 3I/ATLAS and its predecessors, 1I/‘Oumuamua and 2I/Borisov, bore all the qualities of comets, but that the search for genuine alien technosignatures associated with interstellar objects that make our way to our solar system is not unwarranted.
Cosmic Hitchhikers
“Since humanity has sent many of our own spacecraft on interstellar trajectories, we know that it is possible to send probes to other stars,” the study’s authors write. Equally, they argue that a range of different types of technosignatures could essentially “hitchhike” across interstellar distances and arrive with an interstellar object.
“Technology could either be active throughout an object’s interstellar journey, or wake from a dormant state upon arrival in the Solar System,” the authors write. “Defunct technology may also be found, such as spacecraft whose power supplies have long since become inactive.”
Other possibilities include technology that might be buried beneath the surface of an interstellar object. According to this premise, as the surface material begins to sublimate as the object begins to approach our Sun—the same processes producing the Sun-facing coma or “halo” of cometary material currently surrounding 3I/ATLAS—any alien technologies may be revealed through such natural processes. This would allow for the deployment of a once-buried probe, but only if its interstellar carrier manages to reach the vicinity of a star like our Sun.
Other possibilities include interstellar asteroids that are modified to produce “world ships, objects which may include natural structures and other technological features that would allow any “interstellar nomads” on board to utilize generational habitats that could be carried along with any prospective comets capable of spanning interstellar distances.
“Given the extreme distance between star systems, sending physical objects between stars may be advantageous for an extraterrestrial civilization, compared with direct communication,” the authors note.
Four Avenues for Technosignature Searches
In their paper, the team examines four primary categories of potential searches for technosignatures, which include 1) anomalous trajectories (the presence of unexpected accelerations or maneuvers that can’t be explained by natural outgassing or radiation pressure), 2) spectral or coloration anomalies (including unusual reflectance, coatings, or waste heat detectable in the infrared), 3) objects with unnatural shapes such as cylinders or thin “light-sails,” and 4) any detectable transmissions in the form of narrowband radio or optical signals, including lasers, that could indicate intentional or incidental communication.
Interestingly, such observations were made of ‘Oumuamua and Borisov, although no detectable signatures were discernible. As it continues its journey through our solar system, 3I/ATLAS has already been targeted by the Allen Telescope Array and observed by multiple observatories, including NASA’s Webb and Hubble telescopes. Based on all the available data, everything astronomers have observed thus far suggests that these objects have natural origins.
Nonetheless, the authors of the new paper emphasize that there remains a chance that even a few mundane observations—such as monitoring a comet’s rotation, its color, or how it accelerates—could still provide some critical context that may be helpful in identifying potential outliers that might arrive in the future.
Why Technosignature Searches Matter
Currently, with the Rubin Observatory’s Legacy Survey of Space and Time expected to discover anywhere from six to more than 50 interstellar objects in the next decade, the team behind the new study argues that technosignature investigations should not be overlooked and must be incorporated into routine follow-ups. Coordinated campaigns that scour radio, optical, infrared, and radar frequencies could maximize the chances of spotting anything unusual, in the unlikely event that it existed.
For now, although speculation about alien probes captures public imagination, the real value of taking such studies seriously lies in building a systematic framework for distinguishing natural phenomena from any potential anomalies we might find.
“Any potential detection of technosignatures from an [interstellar space object] will require the most stringent and detailed confirmation possible,” the paper’s authors write, underscoring the need for rigorous protocols and independent verification if—or perhaps when—we spot something truly anomalous.
The team’s paper, “Technosignature Searches of Interstellar Objects,” by James R.A. Davenport, et al, appeared on the preprint arXiv.org server on August 22, 2025.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.