In the summer of 2025, the appearance of the sky through surveys was attributed to the appearance of a distant travelling object from outside our solar system, referred to as a comet. Comet 3I/Atlas successfully flew by the sun in October, but later became brighter as it revealed itself for detailed study. SPHEREx was able to record the outburst of the comet, indicating the presence of water and carbon dioxide within it.
Post-Perihelion Outburst
According to NASA, after its near-sun encounter, 3I/ATLAS was observed to have experienced an unexpected outburst. The object was seen to be erupting due to new observations made by NASA’s SPHEREx as part of its infrared survey carried out in December 2025. “Comet 3I/ATLAS was full-on erupting into space in December 2025… causing it to significantly brighten,” Carey Lisse of the Johns Hopkins Applied Physics Laboratory, lead author of a study, was quoted as saying. The erupting parts include water vapour, carbon dioxide, and dust.
Chemical Clues from Afar
The SPHEREx data reveal comet materials that include water ice, carbon compounds, and organic molecules. Research scientists discovered the coma contained methanol, methane, and cyanide. The gas cloud contained high levels of carbon dioxide but contained minimal carbon monoxide, which indicated that 3I/ATLAS developed in a warm environment. Lisse explained that the comet’s ices had undergone extreme heat treatment, which caused their release from the comet core so they resembled the chemical structure of common solar-system comets. The astronomical evidence provides researchers with an exceptional chemical analysis of untouched extraterrestrial material that originated from a different solar system.
