3I/ATLAS as a cosmic messenger: Avi Loeb on the future of interstellar time capsules

Interstellar comet 3I/ATLAS, first reported on July 1, 2025, has since remained a major topic of discussion, not only within the astronomers’ community but also with the general public, as rumors about an alien origin emerged, adding to its mystery. 

Harvard physicist Avi Loeb, one of the most prominent commentators on the comet’s anomalies, wrote in one of his Medium essays that the interstellar visitor displayed no “unusual activity” when it passed by Earth on December 19, 2025, implying that it behaved as a natural comet would.

Now, on December 21, 2025, Loeb published another paper on Medium, in which he proposed the idea that interstellar objects like 3I/ATLAS offer new opportunities for humanity “to send time capsules to interstellar space.”

Having calculated the speed of 3I/ATLAS, which is significantly faster than NASA’s Voyager 1 and 2 spacecraft that are traveling to outer space with a time capsule, Loeb believes that humanity will have a better and quicker chance at making it to interstellar space if they consider “riding 3I/ATLAS.”

Thus, in his December 21 essay, Loeb discussed the benefits of banking on an interstellar time capsule as it would help send messages to extraterrestrial life in outer space more quickly.

Harvard physicist Avi Loeb says interstellar objects offer a faster ride out of the solar system

NASA’s Voyager 1 and 2 spacecraft, which are, at the moment, on their way out of the solar system, have attached to them the “Voyager Golden Records,” which is a “time capsule of sounds, images, music, and messages from Earth.”

The purpose of attaching the Golden Records to the spacecraft is that someday, extraterrestrial life in outer space would come across them. 

According to Loeb, it is a “message in a bottle” for the aliens. While it is a significant step toward making contact with extraterrestrial life, Loeb believes it is a slow process. 

“If we are impatient in establishing physical contact with extraterrestrials, we can attempt to do better in reaching our cosmic neighbors with technological artifacts,” he wrote. 

Loeb suggests foregoing the “traditional” mindset of building a faster spacecraft to reach outer space, and instead focusing on trying to make use of the interstellar objects, like the 3I/ATLAS,  for a quicker time capsule. 

He then pointed out that Voyager 1, which was launched on September 5, 1977, is still on its way out of the solar system at a speed of 17 kilometers per second. 

With that speed, the spacecraft will reach the limit of the solar system in another 28,000 years. 

However, interstellar objects, like 3I/ATLAS, which is traveling at a speed of 60 kilometers per second, will head into outer space in only 8,000 years. 

Thus, Loeb concluded:

“Riding 3I/ATLAS offers the benefit of reaching interstellar space by the year ~10,000 CE instead of the year ~30,000 CE.”

Loeb suggested that experts could attach a record like the Voyager’s on the interstellar visitors, or even carve messages on such asteroids using a high-power laser beam, with the hope that it will get recognized by aliens. 

But even then, no one could predict if the messages being sent out would ever be noticed. As of now, astronomers do not possess such high-tech instruments that can read messages sent by aliens, if any. 

Still, if humans could, Loeb said it would help open “a new discipline on university campuses labeled as ‘Interstellar Archeology.’

That said, he concluded that interstellar objects could be faster messengers from Earth, helping humans relay signs of life into outer space more quickly than before. 

Stay tuned for more updates.