PARIS: Scientists using the James Webb Space Telescope have detected carbon dioxide (CO2) on the frozen surface of Charon, Pluto’s largest moon, for the first time, research revealed on Tuesday.
The discovery, along with the identification of hydrogen peroxide (H2O2), offers new insights into the icy bodies within the mysterious outer reaches of our Solar System.
Charon, which is approximately half the size of Pluto and about the width of France, has long been a subject of interest since its discovery in 1978. The moon was closely observed by NASA’s New Horizons spacecraft during its historic flyby in 2015, revealing a surface primarily covered in water ice and ammonia, which contribute to Charon’s distinctive red and grey hues. However, despite these earlier findings, the presence of CO2 remained an unanswered question.
The recent study, led by Silvia Protopapa of the Southwest Research Institute in Colorado and published in the journal Nature Communications, highlights how Webb’s advanced capabilities allow scientists to probe deeper into celestial objects. Unlike other Kuiper Belt bodies, which may have surfaces obscured by volatile ices like methane, Charon’s surface provided a clearer view for analysis.
Protopapa noted that Charon’s surface serves as a crucial “time capsule,” revealing information about the early formation of the Solar System. The Kuiper Belt, a doughnut-shaped region beyond Neptune, is believed to harbor millions of icy worlds that formed from the protoplanetary disc—a cloud of gas and dust surrounding the young Sun approximately 4.5 billion years ago.
While previous observations from New Horizons did not detect CO2 on Charon, the Webb telescope’s ability to measure longer wavelengths of light has now provided the evidence scientists sought. Protopapa explained that if one could hypothetically stand on Charon’s surface, they would find a mixture of water ice and dry ice—the solid form of CO2.
The detection of hydrogen peroxide is equally intriguing. This chemical, commonly used as a disinfectant on Earth, suggests that Charon’s icy surface undergoes alterations due to exposure to ultraviolet light and solar wind from the distant Sun. These findings add another layer to the understanding of the chemical processes occurring on this remote moon.
Protopapa described the discoveries as a vital “piece of the puzzle” in unraveling the history of the Kuiper Belt and the broader Solar System. Each new finding helps scientists piece together how these distant worlds formed and evolved over billions of years, potentially informing theories about the origins of other planetary bodies, including Earth.
