The SPHEREx space observatory processed an unprecedented set of information that details the chemical composition of the 3I/ATLAS object, confirming the release of a significant amount of organic compounds during its trajectory away from Sistema Solar. The observations, originally carried out in December 2025, demonstrate how solar radiation activated the surface of this cosmic visitor shortly after it passed through perihelion, the point of closest proximity to our star.
Spectral analysis has led to the identification of essential elements for prebiotic reactions, which significantly expands scientific understanding of the distribution of complex matter in the universe. Continuous monitoring has allowed researchers to observe the sublimation process of ices that have remained preserved in the vacuum of space for billions of years, offering a rare opportunity to directly study exogenous materials.
Nasa’s high-precision instruments were able to record specific signatures in the infrared region, highlighting the presence of several volatile materials in the comet’s structure. Entre the main findings include methanol and methane, which were detected in the coma’s emission lines, in addition to cyanide emissions that appeared associated with the dust released by the nucleus. Water vapor showed a drastic increase in volume compared to previous phases of observation, while carbon dioxide dominated the gaseous composition, surpassing carbon monoxide rates.
Detail of chemical mapping
The significant increase in the comet’s brightness, recorded about two months after its closest approach to Sol, served as the necessary trigger for collecting this data. The sublimation of underground ice, which was mixed with rocky material, generated a rich and complex coma around the core. Observations indicate that the morphology of this gas and dust cloud was asymmetrical in some components, aligning itself according to the direction of the incident solar radiation.
The confirmation of the presence of organic compounds containing carbon and hydrogen bonds suggests that these chemical species were trapped in water ice phases. Diferentemente of the preliminary observations carried out in August 2025, the activity recorded at the end of that year showed a much higher chemical diversity, driven by continuous and prolonged exposure to solar heat.
Trajectory and context of the discovery
The 3I/ATLAS object was discovered on July 1, 2025 through an alert system located at Chile, and was quickly classified by the astronomical community as the third confirmed interstellar visitor in history, succeeding the mysterious ‘Oumuamua and comet Borisov. Sua hyperbolic orbit unequivocally indicated a provenance external to our planetary system, opening a rare window for the study of materials formed in other regions of the galaxy.
Additional images captured by the Hubble telescope were essential for tracing the precise route of the object, which crossed the system at a safe distance from the Terra, without posing any risk of collision. The comet nucleus, when responding to the conditions of the solar environment, demonstrated behaviors that allow direct comparisons with local comets, highlighting regional variations in the composition of celestial bodies spread across the Via Láctea.
Impact on planetary science
The detection of these complex molecules reinforces the current theory that the chemical building blocks are common in different stellar systems, and are not exclusive to our local environment. The detailed study of 3I/ATLAS emissions provides crucial clues about the chemical processes that occur in cold interstellar environments and that, theoretically, precede biology.
As the comet continues its return journey to deep space, the outgassing activity tends to progressively decrease. Contudo, the vast archive of spectroscopic data generated by SPHEREx will continue to be analyzed in the coming months to refine current models about the formation of planetary systems and the dispersion of organic compounds in the cosmos.
