This unique sighting has left astronomers baffled.

13:55, Fri, Nov 14, 2025 Updated: 13:58, Fri, Nov 14, 2025

Milky way over huge radio telescopes

The sighting is not from our solar system (Image: Getty)

A mysterious comet has been seen roaring into view after being hidden behind the sun for months. The unique sighting has left experts baffled and wondering where it originated from. Named the 3I/ATLAS, it has been spotted releasing gas and producing dust. 

One out of only 3 confirmed interstellar objects ever detected from our planet, it could be the rarest of its kind. Experts have warned that the comet could be from a completely different planetary system, perhaps on the other side of the galaxy, billions of years ago. 

Qicheng Zhang, a postdoctoral fellow at Lowell Observatory, told Weather.com: “This comet in particular is interesting since it's actually from outside of our solar system, the ‘i’ in 3I stands for interstellar, which means it's an interstellar object. In this case, it's an interstellar comet because we can actually see it outgassing and producing dust.”

A NASA-funded survey telescope in Chile first observed the comet in July. 

While local comets usually drift slowly through our solar system, the 3I/ATLAS is rocketing through with incredible speed. NASA experts compared the speed to that of someone dropping a ball from the top of a building. They believe the oddity in speed comes from the frozen carbon dioxide it has retained. Comets usually lose this carbon dioxide as they approach the Sun. 

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Space station in Earth orbit.

NASA experts are trying to work out its origin (Image: Getty)

It seems the comet has sparked speculation online from social media users about whether it could be a mothership from an alien planet.

One X user said: “It is an alien spacecraft and when it views our beautiful blue planet earth, all bets are off. Aliens with ray guns are not out of the question.” 

Another added: “The aliens are here for an intervention. We will never be the same again. 3IAtlas is an alien ship.”

While one user said: “Did NASA just confirm without saying it outright that this object might be a spaceship?”

Astronomers have confirmed the comet is expected to grow bright enough to be observed through amateur telescopes and can even be photographed by cameras. A NASA-funded survey telescope in Chile first observed the comet reappearing from behind the sun in July this year. It was initially spotted last year, through a network of telescopes designed to hunt for asteroids and comets that could pose a threat to Earth. 

The next James Webber Space Telescope observation will take place in December as scientists battle to understand where the comet has appeared from and what exactly it’s made of.