A bold new proposal from Harvard physicist Avi Loeb suggests that humanity could use the interstellar comet 3I/ATLAS to send messages or ‘time capsules’ into space, potentially reaching extraterrestrial life. Loeb’s groundbreaking paper, published on December 21, 2025, outlines how these natural cosmic travelers could serve as an efficient means of communication beyond our solar system.
Loeb, a prominent figure in astrophysics, argues for a shift in approach regarding interstellar outreach. Instead of relying on traditional spacecraft, he proposes leveraging the natural high-speed trajectory of comets like 3I/ATLAS. This approach could significantly reduce the time it takes for humanity’s messages to reach other civilizations.
Currently, efforts to contact extraterrestrial life involve spacecraft such as NASA’s Voyager 1 and Voyager 2, which are equipped with the Voyager Golden Records. These records contain sounds, images, and messages from Earth, functioning as a time capsule. However, Loeb critiques this method as being unduly slow. In his view, the use of interstellar comets could expedite the process of making contact with potential alien life.
The advantages of using comets are striking. Voyager 1, launched on September 5, 1977, is traveling at a speed of approximately 17 kilometres per second. At this rate, it will take around 28,000 years to reach the edge of the solar system. In contrast, 3I/ATLAS is moving at an impressive speed of 60 kilometres per second, which could shorten the journey time to interstellar space dramatically.
By riding on a comet like 3I/ATLAS, messages from Earth could potentially escape the solar system in just 8,000 years, rather than the millennia required for human-made probes. Loeb estimates that utilizing this natural messenger could allow humanity to reach interstellar space by approximately the year 10,000 CE, a significant advance compared to the current timelines of around 30,000 CE for spacecraft.
The implications of this research are profound. Loeb envisions attaching a record similar to the Voyager Golden Records on future interstellar visitors. Alternatively, messages could be inscribed on the surfaces of these comets using high-power laser technology, creating a permanent marker of human existence in the cosmos.
While the uncertainty surrounding whether these messages would ever be noticed is acknowledged, Loeb emphasizes the potential benefits. Should extraterrestrial life possess the technology to interpret such messages, it could lead to the emergence of a new field of study: Interstellar Archaeology. This discipline would focus on understanding the messages left by other civilizations, providing insights into their cultures and histories.
Loeb’s innovative approach challenges existing paradigms of space communication, offering a glimpse into the future of humanity’s quest for connection beyond Earth. The study of interstellar comets as communication vehicles could open new avenues for exploration and understanding in our pursuit of knowledge about the universe and our place within it.
