In a groundbreaking discovery, a NASA space observatory has detected organic molecules associated with pre-biological chemistry being released by comet 3I/ATLAS, an interstellar object that traversed our solar system in 2025. Data obtained by the SPHEREx telescope reveals the presence of compounds like methanol, hydrogen cyanide, and methane – considered “building blocks” for reactions that may precede life as we realize it – in the material ejected by the comet as it approached the Sun and passed near Earth’s orbit.
The interstellar comet 3I/ATLAS was first discovered on July 1, 2025, by the automated survey system ATLAS, which monitors near-Earth objects, and was quickly identified as one of the rare visitors originating from outside our solar system – bodies born around another star and traveling through interstellar space before crossing into our cosmic neighborhood. Studying these interstellar objects offers a unique opportunity to understand the chemical composition of planetary systems around other stars.
As 3I/ATLAS journeyed through the solar system, it warmed and released an active coma – the characteristic cloud of gas and dust surrounding a comet – which expanded and carried with it complex organic compounds, including methanol, hydrogen cyanide, and methane. While these molecules aren’t life themselves, they are widely considered fundamental chemical ingredients in processes that could lead to the formation of biological structures in suitable environments.
NASA’s Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) was able to capture these chemical signatures between December 8 and 15, 2025, as the comet was departing the solar system. SPHEREx, launched in March 2025, is designed to map the sky in infrared light and study the composition of celestial objects.
The observations from SPHEREx are particularly significant because the telescope can see the sky in 102 different colors of infrared light, providing unique information about the gases and dust within the comet’s coma. This capability allowed scientists to clearly detect the carbon dioxide emission and map the coma over a large scale, extending 10 arcminutes. According to NASA, the coma extends out to at least 348,000 km.
A Window into Primordial Chemistry
Experts believe these observations offer a rare glimpse into the primordial chemical composition of an object likely formed around another star billions of years ago. The presence of these compounds suggests that complex organic matter – which may play a role in processes leading up to life – is common in environments beyond our solar system. While these findings do not indicate the presence of life on 3I/ATLAS, they reinforce the idea that the basic chemical building blocks for life may be widely distributed throughout the universe.
The discovery of an extended carbon dioxide coma and the abundance of water ice in 3I/ATLAS also suggests that interstellar comets may not be so different from the comets that formed around our Sun. As reported by Space.com, the comet brightened significantly during December 2025, releasing water vapor, carbon dioxide, dust, and organic compounds as it exited the solar system.
SPHEREx and the Future of Interstellar Object Research
SPHEREx joined the Hubble and Webb telescopes in studying 3I/ATLAS, gathering data on its size, chemistry, and physical traits. The mission is managed by NASA’s Jet Propulsion Laboratory and is a collaborative effort involving scientists from 13 institutions across the U.S., South Korea, and Taiwan. The data collected by SPHEREx is freely available to scientists and the public.
The ongoing study of 3I/ATLAS and other interstellar objects like it will continue to provide valuable insights into the conditions and materials present in other star systems. Future observations from other NASA missions are planned to further analyze the comet’s composition and behavior.
As 3I/ATLAS continues its journey out of our solar system, scientists will continue to analyze the data collected by SPHEREx and other telescopes, seeking to unravel the mysteries of interstellar chemistry and the potential for life beyond Earth. The findings from this research will undoubtedly shape our understanding of the universe and our place within it.
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