A strange interstellar object, named 3I/ATLAS, has caused quite a stir in the scientific community, sparking intense debates about its origins and what it could mean for Earth.
This comet, first detected by NASA’s Asteroid Terrestrial-impact Last Alert System (ATLAS) in July 2025, is not your typical space rock.
Its peculiar behavior and characteristics have led to some fascinating, though controversial, theories—one of which suggests it could be a spacecraft from another star system.
What is 3I/ATLAS?
3I/ATLAS is the third interstellar object ever recorded to pass through our solar system. It has some unusual traits that have captured the attention of scientists, especially Harvard astrophysicist Avi Loeb.
The object is roughly the size of New York City and is speeding toward Earth at an alarming pace.
Although it's technically a comet, its strange emissions and trajectory have raised questions about whether it might be more than just a natural space body.
One of the most intriguing features of 3I/ATLAS is the emissions it’s been releasing. Unlike typical comets, which expel mostly water vapor, 3I/ATLAS is emitting carbon dioxide, water ice, and carbonyl sulphide - substances that are not normally seen in comets.
In addition, the object is displaying an “anti-tail,” which points toward the Sun instead of away from it, a phenomenon never before observed in a comet.
NASA shared a diagram showing the trajectory of interstellar comet 3I/ATLAS as it passes through the solar system. Credit: NASA
Could 3I/ATLAS Be a Spacecraft?
Avi Loeb, one of the leading scientists to speculate on the nature of 3I/ATLAS, has put forward a rather bold hypothesis: the comet might not be a comet at all.
Loeb, who has made waves in the scientific community with his theories about extraterrestrial life, suggests that 3I/ATLAS could be a technological artifact—potentially a spacecraft from beyond our solar system.
In fact, he has even raised the possibility that it could harbor intelligent life, saying, “The hypothesis in question is that [3I/ATLAS] is a technological artifact, and furthermore has active intelligence."
However, Loeb cautioned that there are two possible scenarios if 3I/ATLAS turns out to be an artificial object: “First, that its intentions are entirely benign and second, they are malign.”
While the idea of a potentially hostile spacecraft might sound alarming, Loeb did not explicitly predict an alien invasion but instead pointed out that this object defies all normal expectations.
October 29: A Potential Turning Point for 3I/ATLAS
As 3I/ATLAS approaches its closest point to the Sun, a date looms large in the minds of those watching its progress: October 29, 2025.
Loeb has suggested that this might be a critical moment for understanding the object's true nature.
Speaking to Mayim Bialik, Loeb jokingly advised people to “take a vacation before [October 29], because who knows what will happen?”
This date is significant due to the Oberth effect, a principle in spaceflight which suggests that spacecraft burn fuel more efficiently when they are at the highest point in their orbit.
Loeb speculates that 3I/ATLAS could be a “mothership” that releases smaller probes toward planets in our solar system as it reaches its perihelion, or closest point to the Sun.
This hypothesis remains speculative, and NASA has not confirmed any such activity.
The space agency has been more cautious, reassuring the public that 3I/ATLAS poses no threat to Earth and will pass safely at a distance of about 170 million miles.
The first image NASA captured of Comet 3I Atlas. Credit: ATLAS/University of Hawaii/NASA
NASA's Findings on 3I/ATLAS
While Loeb’s theory has garnered attention, NASA’s research paints a different picture.
According to the space agency, 3I/ATLAS is most likely a natural object, possibly even billions of years older than our solar system.
NASA scientists have been closely monitoring the comet using instruments like the James Webb Space Telescope, which revealed that 3I/ATLAS is emitting gases like carbon dioxide and water vapor - confirming that it is indeed a comet, though one unlike any ever observed before.
Despite the unusual emissions and behavior, NASA emphasizes that the object poses no danger to Earth.
The comet's closest approach to the Sun will occur around October 30, 2025, when it will come within 130 million miles—just inside the orbit of Mars.
While this is considered a safe distance, the unusual nature of the object has prompted continuous monitoring by space agencies.
Will 3I/ATLAS Lead to a 'Black Swan' Event?
Loeb has raised the possibility that 3I/ATLAS could trigger a “black swan event”—an extremely unlikely and high-impact occurrence that defies all odds and expectations, per Metro.
In essence, a black swan event is something that shakes up our understanding of space and science, leaving experts scrambling to explain it.
In the case of 3I/ATLAS, Loeb has suggested that the object could do something unexpected, especially as it travels behind the Sun, out of our line of sight.
This potential for surprise, combined with its strange characteristics, has led to speculation that the object might behave in ways we’ve never anticipated.
However, while Loeb has speculated on the possibility of something dramatic happening, he has also downplayed fears, advising people not to rush out and stock up on toilet paper.
Where is 3I/ATLAS Now?
Currently, 3I/ATLAS is located behind the Sun, making it difficult for telescopes to track.
However, scientists are keeping a close eye on it, with the next opportunity to observe the object expected on November 2, 2025, when the European Space Agency’s JUICE spacecraft will pass by on its way to study Jupiter.
As of now, the comet is traveling toward its closest approach to the Sun, expected around October 30. After this, it will move beyond the Sun’s glare and continue its journey out of the solar system, with a predicted exit by early December.
While some researchers remain intrigued by the object’s unusual behavior, NASA continues to assert that 3I/ATLAS poses no immediate danger to Earth.