What’s the truth about the mysterious ‘alien’ space rock?

By Dean Murray

The mysterious space rock that passed through our solar system grew significantly brighter as it left, according to scientists.

Researchers say Comet 3I/ATLAS, suggested to be a hostile alien spaceship by one Harvard astrophysicist, saw a "dramatic increase in brightness" two months after the icy body had passed its closest distance to the Sun.

The interstellar visitor, only the third such object to be discovered passing through our solar system, had ignited controversial theories upon its discovery.

Harvard astrophysicist Avi Loeb theorized it could be an artificial alien probe on a reconnaissance mission, due to its unusual glow, trajectory aligning with planetary orbits, and non-natural path.

A scientific paper co-authored by Loeb had warned the object could be a hostile spacecraft for which humanity should be prepared.

More from this section

Understanding weight bias: How it affects your health and what you can do about it

+3

Study suggests brain stimulation can get people to be less selfish

What nervous system dysregulation actually means, according to therapists

It read: “The consequences, should the hypothesis turn out to be correct, could potentially be dire for humanity, and would possibly require defensive measures to be undertaken (though these might prove futile).”

NASA’s SPHEREx space telescope mission viewed 3I/ATLAS in December 2025, when researchers believed the brightening occurred due to a phenomenon associated with comets as they vent water, carbon dioxide, and carbon monoxide into space.

Study lead Carey Lisse, of Johns Hopkins Applied Physics Laboratory, said: "Comet 3I/ATLAS was full-on erupting into space in December 2025, after its close flyby of the Sun, causing it to significantly brighten.

"Even water ice was quickly sublimating into gas in interplanetary space. And since comets consist of about one-third bulk water ice, it was releasing an abundance of new, carbon-rich material that had remained locked in ice deep below the surface.

"We are now seeing the usual range of early solar system materials, including organic molecules, soot, and rock dust, that are typically emitted by a comet."

Yoonsoo Bach, deputy study lead from the Korea Astronomy and Space Science Institute, added: "Our unique space telescope is gathering unprecedented data from across the universe. But in this case, our galaxy delivered a piece of a faraway star system to us only a few months after launch, and SPHEREx was ready to observe it. Science is sometimes like that: you’re in the right place at the right time."