A mysterious visitor from beyond our solar system is drawing the attention of astronomers, scientists, and even the United Nations.
Known as 3I/ATLAS, this newly detected interstellar comet has sparked an official response from the International Asteroid Warning Network (IAWN) - a global group of astronomers endorsed by the UN that focuses on planetary defense against space threats.
This marks the first time IAWN has launched a campaign targeting an interstellar object.
Is it just a comet—or something more?
Interestingly, this campaign announcement follows a provocative White Paper submitted to the United Nations just weeks earlier, on September 30, 2025.
The paper—co-authored by Avi Loeb, Omer Eldadi, and Gershon Tenenbaum—proposed a coordinated global effort to monitor interstellar visitors like 3I/ATLAS, in case they’re carrying more than cosmic dust, per Medium.
"Black swan events with small probabilities must be considered seriously if their implications to the future of humanity are large," the authors stated.
Loeb, a Harvard astrophysicist, suggests that some interstellar objects might even carry alien technology.
To quantify this possibility, he developed the "Loeb Scale," and based on eight unusual traits, 3I/ATLAS scored a 4 out of 10—making it one of the most intriguing space objects ever observed.
The 8 strange qualities of 3I/ATLAS
These are the red flags that raised eyebrows among scientists: Suspicious alignment: Its trajectory is within 5 degrees of the solar system’s planetary plane—an alignment with a likelihood of just 0.2%.
- Unusual jet behavior: In July and August 2025, it emitted a sunward-facing jet (also called an anti-tail) that was not due to perspective—something unseen in typical comets.
- Massive and fast: The object is roughly a million times more massive than 1I/`Oumuamua and a thousand times more massive than 2I/Borisov—while moving faster than both. Loeb estimates the chance of this combination at less than 0.1%.
- Close encounters: Its path took it uncomfortably close to Mars, Venus, and Jupiter, while avoiding Earth during perihelion. Loeb estimates this timing had just a 0.005% chance of occurring randomly.
- Industrial materials?: The gas plume around 3I/ATLAS has far more nickel than iron—a trait found in man-made nickel alloys—and a strange nickel-to-cyanide ratio, unlike any known comet. Estimated likelihood: under 1%.
- Low water content: Only 4% of its mass appears to be water, whereas typical comets are mostly made of ice.
- Extreme light scattering: It showed an extreme form of negative polarization, unprecedented even among known interstellar comets. Again, the chance of this being random is estimated below 1%.
- Coincidence with the “Wow! Signal”: The object’s path aligns within 9 degrees of the direction where the famous 1977 radio “Wow! Signal” originated, with a 0.6% chance.
When combined, these odds point to a probability lower than one in ten quadrillion (10^16). That’s why scientists believe it’s worth throwing every observational tool at this cosmic mystery.
Could we intercept it with a spacecraft?
Unfortunately, humanity wasn’t prepared for this unexpected visitor. No existing spacecraft is in position to intercept 3I/ATLAS, per the Daily Mail.
However, in a recent study, Loeb and collaborators Adam Hibberd and Adam Crowl found that NASA’s Juno spacecraft - currently near Jupiter - could have intercepted the object at its closest approach to the gas giant on March 16, 2026, if it still had its original fuel.
This concept was endorsed in a letter from U.S. Congresswoman Anna Paulina Luna to NASA’s Interim Administrator Sean Duffy on July 31, 2025, recommending such a mission.
Watch the skies: could it release probes?
The next major milestone comes on October 29, 2025, when 3I/ATLAS reaches perihelion—its closest point to the Sun. Loeb explains why this is the perfect moment to watch for signs of alien tech.
“The clearest technological signature of 3I/ATLAS would be a maneuver or the release of mini-probes near perihelion,” he writes. “An impulse in the direction of the peak velocity or opposite to it, would maximize the gain or loss of kinetic energy.”
This energy-efficient trick, known as the Oberth effect, would allow any craft—or probe—launched from 3I/ATLAS to use the Sun’s gravity to slingshot toward inner planets like Earth.
“If 3I/ATLAS is a massive mothership, it will likely continue along its original gravitational path and ultimately exit the Solar system, while releasing mini-probes near perihelion that might take advantage of the Sun’s gravitational assist as they maneuver towards planets like the Earth.”
Loeb’s Galileo Project observatories are already scanning for unusual activity that might suggest the arrival of such probes in Earth’s vicinity.
3I/ATLAS makes its closest pass by Earth in December
Mark your calendars - on December 19, 2025, 3I/ATLAS will pass nearest to Earth. And while we won’t be sending a spacecraft to greet it, ground-based observatories around the world will be watching intently.
As Loeb puts it: “Here’s hoping that we will know more about our dating partner in this interstellar blind date by Christmas.”