Beyond Our Solar System — Massive Interstellar Object 3I/ATLAS Rewrites The Comet Rulebook

That imbalance suggests it may have formed in a completely different environment—perhaps in the icy outskirts of another star system, or closer to a CO₂ “frost line” where water was scarce. Researchers from Caltech’s SPHEREx mission confirmed the findings, noting that its spectral signature implies an alien chemistry not represented in our local comet catalogues.

“This is the first truly carbon dioxide–dominated comet we’ve ever observed,” one researcher remarked. “It challenges our assumptions about where and how icy bodies form in planetary systems.”

Unusual Light, Unusual Dust

Even its light behaves strangely. Polarimetric readings—measurements of how light scatters off dust—show a pattern unseen in any other known comet. The data suggest that 3I/ATLAS’s dust particles are structured differently, possibly denser or metallic in composition. This polarisation signature could mean that interstellar comets aren’t just distant cousins of our own, but a completely different class of celestial body.