Scientists have proposed a new theory on how Pluto’s largest moon, Charon, came to be. The researchers suggest that a “kiss-and-capture” event occurred when Charon crashed into Pluto and the pair briefly rotated together before breaking apart. This process left each body largely distinct and intact, with some material exchanged.
According to Dr. Adeene Denton, first author of the research from the University of Arizona, this theory is supported by computer models that took into account Pluto’s strength, previously overlooked in previous collision simulations. Since Pluto and Charon are composed of rock and ice, they respond like solid materials under stress, rather than behaving as fluids.
The “kiss-and-capture” event could have led to the subsequent geologic evolution of Pluto and Charon, potentially resulting in subsurface oceans. The impact also dumps heat into Pluto, followed by heating as Charon moves away, which could mark the beginning of a new geological era. This theory is further supported by the fact that eight out of ten largest Kuiper Belt objects have a large satellite like Charon, suggesting that “kiss-and-capture” events may have been prolific across the Kuiper Belt as the solar system formed.
Source: https://www.theguardian.com/science/2025/jan/06/new-theory-how-pluto-got-its-largest-moon-charon