ATLAS Comet Shocks Scientists: Fresh Questions Arise in NASA’s Latest Update

 3I/ATLAS: The Interstellar Visitor With Mysteries

In July 2025, astronomers using the ATLAS telescope in Chile discovered a new comet, later named 3I/ATLAS — the third confirmed interstellar object ever observed passing through our solar system. Observations showed it was moving at high speed on a hyperbolic trajectory, meaning it is not gravitationally bound to the Sun and will not return. 

As 3I/ATLAS approached the Sun, scientists worldwide mobilized — space telescopes and ground observatories recorded data, eager to learn about the comet’s composition, behaviour, and origin. 

NASA confirmed that 3I/ATLAS reached perihelion (closest approach to the Sun) on 30 October 2025, just inside Mars’s orbit.  The comet came no closer to Earth than about 1.8 astronomical units — roughly 170 million miles — so it poses no impact risk. 

Initial images showed a typical cometary coma — a fuzzy cloud of gas and dust surrounding a solid icy nucleus — and a tail, consistent with expectations for a comet. 

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What’s Puzzling Scientists Now

Even though 3I/ATLAS behaves “like a comet,” recent observations have revealed several unusual features that challenge scientists’ understanding:

Unusual composition: Infrared observations by the James Webb Space Telescope (JWST) found that the comet’s coma is highly enriched in carbon dioxide (CO₂), with a CO₂/H₂O ratio far higher than typically seen in Solar System comets.  This suggests the comet formed under very different conditions than our regular comets.

Strange polarization behavior: A recent polarimetric study found that 3I/ATLAS displays a deep, narrow negative polarization branch — a signature unlike any comet or asteroid observed before, hinting at unusual surface or dust properties. 

Trajectory oddities and tail behaviour: Some analyses report non-gravitational acceleration, sunward jets, or tail features that don’t align with conventional comet behavior. These anomalies have led a few scientists (and some outside mainstream science) to speculate — cautiously — about whether 3I/ATLAS could be something more exotic than a simple comet. 

Despite these puzzles, NASA remains conservative and careful: after reviewing all data, the agency continues to classify 3I/ATLAS as a natural interstellar comet. According to NASA scientists, while some behaviors are surprising, they are still consistent with natural explanations — a comet from another star system with unusual chemistry and composition. 

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🔭 Why 3I/ATLAS Matters

Because it comes from outside our solar system, 3I/ATLAS offers a rare chance to study material formed in another star system — a cosmic sample of alien origins. Its unusual composition and behaviour provide valuable data on how different solar systems form comets, how interstellar objects evolve under cosmic radiation, and how diverse the cosmos might be.

Even though questions remain — about its composition, tail dynamics, and unusually polarized light — scientists are collecting as much data as possible before 3I/ATLAS disappears into deep space forever.

In short: 3I/ATLAS remains a comet, by NASA’s classification — but it’s a comet full of surprises, challenging our assumptions, and deepening the mystery of what lies beyond the solar system.