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NASA's SPHEREx mission tracked interstellar comet 3I/ATLAS in December 2025, revealing organic molecules such as methanol and cyanide and a brightness surge after its closest approach to the Sun. The comet's coma was observed to contain carbon dioxide, water, and rocky materials, indicating active sublimation of subsurface ice.

The comet was discovered in July 2025 and is one of only three known interstellar comets. SPHEREx aims to map the cosmos and understand the origins of life, and its observations contribute to ongoing studies of comets and asteroids.