NASA’s SPHEREx space telescope has detected organic molecules in rare interstellar comet 3I/ATLAS, offering new insights into material formed beyond the solar system.

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• NASA’s SPHEREx observed interstellar comet 3I/ATLAS in December 2025, marking only the third confirmed interstellar object passing through the solar system.

• Infrared analysis detected organic molecules including methanol, methane and cyanide, highlighting complex chemical compositions that can form through non-biological processes in space.

• SPHEREx used 102 infrared wavelengths to study the comet’s composition, enabling detailed mapping of molecules otherwise invisible to optical telescopes.

• Scientists observed a significant brightening nearly two months after perihelion, attributed to delayed sublimation of subsurface frozen ices.

• Sublimation released gases forming a coma rich in water vapour, carbon dioxide and carbon monoxide, enhancing cometary activity well after solar heating peak.

• Observations suggest deep, pristine ices erupted later, releasing carbon-rich material preserved beneath the surface for billions of years.

• Researchers detected soot, rocky dust and large solid fragments, indicating ejection of heavier material compared to typical solar system comets.

• The findings demonstrate SPHEREx’s capability to study rare interstellar visitors and enhance understanding of pre-solar material from distant star systems.