SpaceX CEO Elon Musk Responds To Wild Speculation That 3I/ATLAS Is An Alien Spaceship

Elon Musk, the world's richest man and CEO of private space firm SpaceX, has weighed in on the topic of interstellar object 3I/ATLAS, and the hypothesis that it may be an alien mothership (spoiler alert: it isn't).

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On July 1, 2025, astronomers at the Asteroid Terrestrial-impact Last Alert System spotted an object hurtling through our Solar System at a velocity that would soon take it right back out again. Soon, other telescopes turned towards the object, now known to be a comet, and found that it was indeed on an escape trajectory. The Solar System had its third confirmed interstellar visitor, after 2017's 1I/'Oumuamua and 2019's 2I/Borisov.

It's an interesting object, and one scientists are very keen to get a better look at. The key reason being that it is an interstellar object that may have been traveling alone for around 10 billion years, a time capsule from an earlier age of the universe, and a traveler from a different part of our galaxy.

But the reason why it has drawn a little more attention is because of wild (and incorrect) speculation that it may be an alien spacecraft. This was first proposed by Harvard astronomer and physicist Avi Loeb, who initially proposed it as a pedagogical, or "teaching", exercise when the comet was on its way to perihelion, the closest approach to the Sun, which occurred on October 30. According to Loeb, an alien spacecraft wishing to conceal a maneuver may choose to do so when it reaches perihelion, where it will be hidden from our view behind the Sun. 

While this hypothesis has been dismissed as unnecessary by astronomers at NASA, SETI, and pretty much the entire astronomical community, now it is time for the real heavyweights to weigh in: Elon Musk and UFC commentator turned podcaster Joe Rogan.

In an interview for The Joe Rogan Experience podcast, Rogan asked the X owner if he was paying attention to 3I/ATLAS, "whatever it is". 

Musk was quick to step in and shut down alien speculation, referring to the object, correctly, as a comet.

"One thing I can say is like, look, if I was aware of any evidence of aliens, Joe, you have my word. I will come on your show and I will reveal it on the show," Musk told Rogan. 

Unhelpfully, Musk did briefly say "it could be aliens, I don't know", before Rogan weighed in again, saying that Loeb had said something that day about how the object had "changed course". While it is unclear exactly what Loeb quote he was referring to, it is likely that the object's trajectory has changed slightly, but this is not itself evidence that the object is a spacecraft making a maneuver.

As explained by Loeb himself in a blog post, 3I/ATLAS has undergone a "radial acceleration away from the Sun of 1.1x10^{-6} au per day squared", as well as a "transverse acceleration relative to the Sun’s direction of 3.7x10^{-7} au per day squared".

That might sound odd, but it is not unexpected, nor a sign that it is an alien spaceship. As comets approach the Sun, they are heated and lose mass by outgassing, where the volatile ices on their surface vaporize, and conservation of momentum tells us the object undergoes a resulting acceleration. Its course changed because it's a comet approaching the Sun, behaving like a comet approaching the Sun.

Next, Rogan brought up the unusual amount of nickel on the object, implying that this could be a sign that it is an alien spacecraft, adding incorrectly that the only way that exists on Earth is in industrial alloys. Here, Musk was a lot more helpful in showing his space credentials.

"No, there are definitely comets and asteroids which are primarily made of nickel," he told the host. "So the places where you mine nickel on Earth are actually where there was an asteroid or comet that hit Earth that was nickel-rich. Nickel-rich deposits... are from impacts. You definitely didn't want to be there at the time because anything would have been obliterated. But that's where the sources of nickel and cobalt are these days."

With this, Rogan moved on to his next point, reading a Reddit post quoting an Avi Loeb blog post about the "first hint of non-gravitational acceleration that something other than gravity is affecting its acceleration, meaning something is affecting its trajectory beyond gravity was indicated".

As already explained, this was likely the result of outgassing of a comet. Rogan again tried to say that nickel was only found in manufacturing. 

Musk pointed out a second time that there are plenty of nickel-rich objects out there in the cosmos, before pivoting to his real area of expertise, pointing out "It'll be a very sort of heavy spaceship if you make it all out of nickel."

With Musk not playing ball on the "alien mothership" scenario, the two moved on to how much destruction the object would cause if it hit Earth. 

"It would like obliterate a continent type of thing," Musk told Rogan. "Maybe worse. Probably kill most of human life. If not all of us," he added, though there is no suggestion that the object could hit Earth at all.

All in all, Musk was keen to stress that there is a natural explanation for the object. As every astronomer has been screaming for the past few months, it is a comet.