Why a Comet Brightened as It Traversed the Solar System

The Mysterious Space Rock That Brightened as It Left

A mysterious space rock that passed through our solar system has captured the attention of scientists due to its unusual behavior. According to recent observations, the object became significantly brighter as it moved away from our solar system.

The interstellar visitor, known as Comet 3I/ATLAS, has sparked a lot of debate among researchers. Initially, some speculated that it might be an artificial alien probe rather than a natural comet. This theory was proposed by Harvard astrophysicist Avi Loeb, who suggested that the object’s unusual glow and trajectory could indicate an artificial origin.

Loeb’s hypothesis raised concerns about the potential implications for humanity. A scientific paper co-authored by him warned that if the object were indeed an alien spacecraft, it could pose a significant threat. The paper stated: “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).”

Despite the controversial theories, NASA’s SPHEREx space telescope mission observed 3I/ATLAS in December 2025. At that time, scientists believed the brightening was caused by a natural phenomenon associated with comets. As the icy body vented water, carbon dioxide, and carbon monoxide into space, it began to glow more intensely.

Carey Lisse, the study lead from Johns Hopkins Applied Physics Laboratory, explained that the comet was erupting into space after its close flyby of the Sun. He said: “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.”

Lisse added that the comet was emitting a range of materials typically found in early solar system objects, including organic molecules, soot, and rock dust.

Yoonsoo Bach, deputy study lead from the Korea Astronomy and Space Science Institute, highlighted the significance of the observation. She said: “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.”