Neil deGrasse Tyson And Professor Brian Cox Talk Interstellar Comet 3I/ATLAS And Alien Spacecraft: "It's Older Than Us"

American astrophysicist and science communicator Neil deGrasse Tyson, and English physicist, science communicator, and musician Professor Brian Cox have given the world their thoughts on interstellar comet 3I/ATLAS, and the unnecessary hypothesis that it could be an alien spacecraft.

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First up, the recap. On July 1, 2025, the Asteroid Terrestrial-impact Last Alert System (ATLAS) did its job brilliantly (pat pat), detecting an object hurtling through our Solar System on a trajectory that could only mean one thing: the object is interstellar, a visitor born around a distant star. 

It was quickly discovered to be a comet, displaying classic cometary behavior. That doesn't mean it isn't interesting. We are talking about an interstellar comet that may have traveled for 10 billion years before its encounter with our star, a time capsule from another time in the universe and another area of our galaxy.

The reason why Cox and deGrasse Tyson were talking about it, however, is in the context of misinformation, and unnecessary and silly claims that the comet could be an alien spacecraft.

"[3I/ATLAS is] a fascinating thing that current estimates say is maybe 7, 8 billion years old, has come from a distant star system older than our Solar System. An unprecedented opportunity to observe material that's coming from a distant star system. And yet you see people going 'it's aliens'," Cox said in a wide-ranging episode of StarTalk. 

"I think this is what Carl Sagan meant. That the reality of it that this is something that formed before the Earth formed, and is visiting our Solar System and going back out into interstellar space, is more interesting than trying to say that it's [aliens]."

The two, and Star Talk regular and standup comedian Chuck Nice, went on to make fun of the idea that the comet is an alien spacecraft. If it were, then aliens clearly have a thing for creating spacecraft that behave exactly like comets, for no obvious gain to themselves.

"By the way, if it's an alien spaceship, it's not spending much time [here]," Cox added. "It misses the Earth by what is it? Two astronomical units."

For accuracy (and not to dunk on Cox, it's difficult to remember figures off the top of your head), we should point out that the comet will make its closest approach to Earth on December 19, 2025, missing us by 1.8 astronomical units, or 270 million kilometers (168 million miles). If it were here to check out Earth, that's a pretty wide miss, and nowhere near as close as its approach to our largest gas giant, Jupiter.

"It goes flying through the Solar System, flying off again. It's been traveling for something like probably about 7 billion years or something like this," Cox said, before Nice added "and you miss your exit".

"Seven billion years. We'll go we'll go around again. We'll make a course correction and go around again. I'm sure it'll be fine. Not much will have changed in only seven billion years," Cox continued.

As pointed out by Cox and deGrasse Tyson, the object is on a hyperbolic trajectory, and will soon leave our Solar System, before it continues on its path and orbit around the galaxy. We are getting a brief glimpse of an ancient object as it passes us by. Isn't that enough to get excited about, without pretending that it's aliens?