'Potentially hostile alien threat' is undergoing planetary defence exercise by UN

A comet some consider to be 'a potential hostile alien threat' has been confirmed by the United Nations (UN) as a planetary-defence exercise.

So, 3I/ATLAS is causing all sorts of debate in the science world as some experts think it could be a sign of aliens.

Meanwhile, NASA say the mysterious interstellar object is simply a comet, and is just the third on record to ever enter our solar system, though it has been exhibiting some bizarre new behaviour.

After its discovery in July 2025, 3I/ATLAS reached its closest approach to the Sun at about at about 153,000 miles per hour on 29 October.

Size wise, its nucleus is thought to be somewhere between about 0.32 km and a few km in diameter. Though no one really knows because the bright coma made up of gas and dust makes the nucleus hard to isolate.

3I/ATLAS is the third interstellar object on record to enter our solar system (YouTube/NASA)

Now, a document published by the UN and the International Asteroid Warning Network (IAWN) has since stated that the comet is officially part of a planetary-defence exercise, which usually takes place once a year.

“While it poses no threat, comet 3I/ATLAS presents a great opportunity for the IAWN community to perform an observing exercise due to its prolonged observability from Earth and high interest to the scientific community,” the document reads.

“This 3I/ATLAS campaign is the 8th IAWN observing exercise since 2017 — IAWN holds these exercises roughly once a year.

It's impossible to accurately determine its size (YouTube/NASA)

“IAWN had been planning to do a Fall 2025 comet campaign since 2024 to exercise capabilities for measuring the position of comets, which pose additional astrometric challenges as they appear as fuzzy extended objects compared to point-like asteroids in a telescope’s field of view.”

And they aren't the only ones, as the European Space Agency (ESA) said they are also monitoring it for planetary defense, writing: "Even though 3I/ATLAS poses no threat, it was a valuable exercise for planetary defence. ESA routinely monitors near-Earth asteroids and comets, calculating orbits to provide warnings if required."

Since 3I/ATLAS was spotted, however, Professor Avi Loeb of Harvard University thinks it’s plausible that 3I/ATLAS could be an artificial object.

Loeb argues that its supposed large size, high speed, and trajectory behind the Sun add to the 'confusing' statement from NASA, who insist that it's a comet.

Some experts think it could be a sign of aliens (YouTube/NASA)

He told LADbible: "The truth is not decided by authority. NASA has no authority over nature to tell us what nature is. I mean, it's decided by data. There are many anomalies of this object, so you can't say conclusively that it's one thing or another.

"What we should be is curious, you know, wonder about what it is, and just collect more data.

"I find it really peculiar for NASA, it's sort of the signature of a bureaucratic body where hierarchy decides what is being done, and somehow, someone in the leadership decided to make a very bold and strong statement without attending to the data."

The scientist hopes to have a lot more data by Christmas, and claims 3I/ATLAS’s trajectory is 'finely tuned' so it could get to a point where it swings 53 million miles of Jupiter.