The European Space Agency (ESA) has released a video of interstellar comet 3I/ATLAS, constructed from images taken by a probe headed to gas giant Jupiter. Meanwhile, the Search for Extraterrestrial Intelligence (SETI) has released the results of a technosignature search of the same object.
First, a brief recap for people who have not heard of our visiting comet so far. Last year on July 1, the Asteroid Terrestrial-impact Last Alert System spotted an object speeding through our neck of the galaxy. On an escape trajectory, it was soon determined to be our third interstellar visitor, after 1I/Oumuamua and 2I/Borisov, and an interstellar comet at that.
Scientists hoped to learn much more about interstellar visitors from it. Particularly exciting, the object got close enough to the Sun during perihelion – or its closest approach to our star – for ices and volatiles to sublimate, allowing astronomers to study its isotopic ratios and composition. This potentially allows us to learn about the environment it came from, and narrow down what part of the galaxy it formed in, with the latest studies suggesting it emerged in the Milky Way’s thick disk, though further study is needed.
The object has been captured by several orbiters around Mars, as well as the Perseverance rover actually on the Red Planet. As 3I/ATLAS approached perihelion, it was frustratingly out of view of telescopes based on Earth. But ESA realized that their Jupiter Icy Moons Explorer (JUICE) spacecraft, currently en route to Jupiter following a Venus flyby, was perfectly situated to observe the comet shortly after its closest approach. Though campaigns like this would normally take nine months of planning, the team got to work to make the most of their good timing and fortune.
“All this campaign was unexpected for everybody!” Olivier Witasse, ESA Project Scientist, told IFLScience ahead of the unexpected observations. “For JUICE, indeed, we are in a cruise phase during which there are thermal constraints, being relatively close to the Sun (with respect to the science phase around Jupiter). Therefore, no payload activities were expected to take place at this moment. However, given the uniqueness of these observations, it was decided to prepare this extra observation planning.”
Between November 2 and November 25 JUICE observed the comet, using five of its instruments to take measurements of it. Unfortunately, due to a number of factors, the team had to wait until February to receive data from JUICE.
“As Juice was close to the Sun at the time, it was using its main high-gain antenna as a heat shield. It was using its smaller medium-gain antenna to send data back to Earth at a much lower rate. It was also far from Earth, on the other side of the Sun.” ESA explains. “The team did quickly download a quarter of a Navigation Camera (NavCam) image, which revealed an active comet. The rest of the Juice’s observations of 3I/ATLAS only arrived in February 2026. Instrument teams are currently analysing the data to see what they reveal.”
Using the data, the team has now put together a short video, showing our interstellar visitor cruising through our Solar System.
So, what about the technosearch? Though most scientists dismiss the “alien spacecraft” hypothesis, given that all of its behavior can be explained by it being a comet, there are a few conspiracy theorists and astronomers out there who have suggested it might not be natural. This hypothesis has been rejected by NASA and SETI scientists, but since it is here and we have the instruments, why not have a quick check to see if it is emitting techosignatures anyway?
In a new study, which has not yet been peer reviewed, astronomers from Beijing Normal University and Dezhou University in China did just that. Using the Five-hundred-meter Aperture Spherical Telescope (FAST), the team searched the comet for technosignatures on four separate dates between October 2025 and January 2026. These were when 3I/ATLAS was closest to Mars, near to the Sun as observations would allow, when it was closest to Earth, and shortly after its closest approach to our planet.
The team was looking for narrowband signals. It is thought that aliens may use narrowband signals, like we do, for their efficiency in long-distance communication, as well as how easy they are to distinguish from the noisy, messy cosmos. As you might expect, given that the title for the article isn’t “HAVE WE FOUND ALIENS??”, the team did not identify anything definitive.
“After visual inspections, almost all potential candidates we obtain are obvious false positives and rejected as RFIs [radio frequency interference]except five chirp-up signals detected on January 5, 2026, which only appear in the central beam,” the team explains in their paper.
While those five chirps sound exciting, further work from the team put an end to hopes of signatures from an alien probe.
“These five chirp-up signals are finally rejected as instrumental RFIs instead of signals of interest, due to the consistency with the clock oscillator intermodulation in frequencies and inconsistency with the expected drift rate,” they wrote.
This is not the first team to search the object for technosignatures, with Breakthrough Listen conducting its own search in December. That search also revealed no signs of intelligent activity, which is unsurprising for a comet.
ESA is currently sifting through the data it collected, and will meet to discuss what it has found next week. As well as this, the team is feeling even more assured that JUICE will capture useful data when it arrives at the Solar System’s largest gas giant.
“At Jupiter, we will perform flybys of the icy moons at a high cadence, sometimes only a couple of weeks apart,” Federico Giannetto, Juice Spacecraft Operations Engineer, added in a statement. “The 3I/ATLAS campaign has made me even more confident that Juice can quickly achieve scientific objectives with short warning times, and that complex operations can be planned and executed within very limited timeframes.”
The paper is available on the pre-print server arXiv.
