Prof. Brian Cox debunks 3I/ATLAS alien-origin rumors with Neil deGrasse Tyson

Musician and physicist Professor Brian Cox recently spoke about the interstellar object 3I/ATLAS, due to make its closest approach to Earth on December 19, 2025, sharing his honest take on rumors that it is an alien spacecraft. 

In a December 10 episode of StarTalk, Prof Cox sat down with Neil deGrasse Tyson and Chuck Nice to discuss the rapid spread of misinformation among people about various subjects, including the interstellar object 3I/ATLAS.

According to Cox, it is illogical to believe that 3I/ATLAS can be an alien spacecraft or even technological in nature.

He branded such alien-origin rumors and hypotheses as unfounded, emphasizing that evidence and “reality” show 3I/ATLAS is simply an interstellar comet visiting the solar system before returning to interstellar space.

His analysis of 3I/ATLAS, whose first reported discovery was made in July 2025, aligns with the narrative NASA has been trying to promote that it is nothing but a comet and poses no threat to human life. 

However, it is in stark contrast with the studies and claims of Harvard physicist Avi Loeb, who, since its discovery, has consistently spoken about the anomalies of 3I/ATLAS, urging others to remain skeptical about its origin. 

While he has not concluded that 3I/ATLAS is an alien object, he remains open to that possibility and insists others do the same.  

Brian Cox believes it is “more interesting” just to accept that 3I/ATLAS formed before the existence of Earth and is simply a comet

While speaking about how misinformation was keeping people from real mysteries and true stories, Cox began talking about the buzz around 3I/ATLAS. 

To him, 3I/ATLAS is a “fascinating thing” with an estimated age of about 7-8 billion years, that entered Earth’s solar system from a “distant star system” far older. 

He reiterated that the interstellar comet formed before the existence of Earth, providing scientists and astronomy enthusiasts with an “unprecedented opportunity” to observe and study material that had traveled a great distance. 

However, he was disappointed to see that despite the chance to witness something so “fascinating,” people engaged in alien-origin theories and gossip.

Drawing a reference to astronomer Carl Sagan, Cox stated:

“You know, that’s what I think is what Carl Sagan meant that the reality of it that this is something that formed before the Earth formed, and visiting our solar system and going back into interstellar space is more interesting than trying to say that it’s some kind of completely useless [aliens].”

Cox went on to joke about such unfounded theories, saying that if 3I/ATLAS is indeed an alien spaceship, “it’s not spending much time” on Earth, noting that it will fly past it on its closest approach. 

3I/ATLAS will be at a distance of approximately 168 million miles or 270 million kilometers from Earth on December 19. 

Noting how 3I/ATLAS will “miss” Earth by almost 1.8 astronomical units, Cox dismissed such alien theories, implying they were unimaginable. 

“Seven billion years. We’ll go around again. We’ll make a course correction and go around again. I’m sure it will be fine. Not much will have changed in only seven billion years,” Cox continued to joke.

Cox further stressed that 3I/ATLAS is a natural comet and pointed out that it is on a hyperbolic orbit and does not have a chance to come back. 

Cox has consistently claimed that 3I/ATLAS is simply a comet, as he did on October 29, 2025, saying it is “entirely natural in origin” and is composed of “carbon dioxide and water ices and bits of other stuff.”

Stay tuned for more updates.