UN confirms planetary defences will observe interstellar comet racing through Solar System
The 3I/ATLAS comet was discovered in July 2025
The Earth's planetary defenses will observe an interstellar comet flying through the Solar System, the United Nations has confirmed.
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A team of scientists from the International Asteroid Warning Network (IAWN) will track the 3I/ATLAS comet for a two–month period starting from November 27 as the space rock nears the planet.
The initiative forms part of efforts to bolster global readiness against so-called Near-Earth Objects (NEOs).
The UN said on its website: “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.
"This 3I/ATLAS campaign is the 8th IAWN observing exercise since 2017 – IAWN holds these exercises roughly once a year."
It added that its "comet campaign" had been planned long in advance of 3I/ATLAS's discovery in July 2025.
Read more: Mysterious space object may be oldest comet ever discovered, scientists say
"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," the UN added.
It comes after experts warned the comet could have a close "encounter" with Jupiter, the largest planet in our solar system, sparking fears of a "course-altering" collision.
Astronomers are uncertain of the comet’s origins, but some have suggested it has travelled from the Milky Way's "thick disk."
Chris Lintott, Professor of Astrophysics and Citizen Science Lead at the University of Oxford, said: "This thing is coming in much faster than the other two, but it is actually within the range of velocities that we would predict in objects.
"So we don't think that's notable, but it's moving fast up and down relative to the plane of the galaxy in a vertical velocity, so it gives us a clue about where it's from. Our model predicts that it's from a star in the thick disc of the galaxy.
"[Comet 3I/ATLAS] is probably from an old star in the thick disc, and we think that it's likely that this thing's been out there for longer than the age of the Solar System."
The interstellar comet was discovered on July 1 2025 by the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in Chile.
It is just the third visitor of its kind ever confirmed to be passing through our Solar System.