Extraterrestrial

Avi Loeb: 3I/ATLAS may have been the source of the 'Wow!' signal

By T.K. Randall
September 30, 2025 ·  26 comments

Image: AI-generated (Midjourney) Astronomers have been listening out for extraterrestrial signals for years, but one case - that of a strange signal picked up by a school telescope at Ohio State University over 40 years ago - has long remained one of the most tantalizing and perplexing examples ever recorded.

Originating in the globular cluster of M55 in the constellation Sagittarius, the peculiar signal lasted approximately 72 seconds. Astronomer Jerry Ehman, who was the first to examine the computer readout, famously wrote the word 'Wow!' on the page.

Although most experts have since dismissed the signal as naturally occurring, the specifics surrounding its source have remained a topic of debate for decades.

Now, though, Harvard's Avi Loeb has written a new piece in which he suggests that the enigmatic interstellar visitor 3I/ATLAS might actually be the originator of this mysterious signal.

According to his findings, back in 1977 when the Wow! signal was received, 3I/ATLAS was situated in the same approximate direction as the origin of the signal.

"Hence, the 'Wow!' signal was separated by approximately 4 degrees in RA and 8 degrees in Dec from the direction of 3I/ATLAS," he wrote."The chance of two random directions in the sky being aligned to that level is about 0.6 percent."

Loeb then went on to consider what would happen if we received a signal from 3I/ATLAS.

"The urgency of a response would depend on the rank of the object on the Loeb Scale," he wrote.

"Rank 10 would suggest an imminent threat akin to a visitor to our backyard who is capable of approaching the front door, requiring an immediate response."

"But even a low rank would necessitate a contingency plan because of the major implications to humanity if the threat is realized."

As things stand, however, there is no evidence to suggest that 3I/ATLAS poses any sort of threat.

Source: Avi Loeb Medium | Comments (26)

Tags: Interstellar, Avi Loeb