A groundbreaking new theory suggests that Pluto's moon Charon may have been captured in a "kiss and capture" scenario billions of years ago, offering a fresh perspective on the formation of planetary systems. Led by NASA postdoctoral fellow Adeene Denton at the U of A Lunar and Planetary Laboratory, this study challenges long-standing models of moon formation. Instead of the traditional collision model, the researchers propose that Pluto and Charon had a brief, icy encounter, where the bodies collided, stuck together for a short time, and then separated while remaining gravitationally bound.

The new theory is based on a key insight: the structural integrity of cold, icy bodies like Pluto and Charon, which was previously overlooked in collision models. This factor is crucial for understanding how these smaller, colder planetary bodies interact compared to larger, hotter ones like Earth. Unlike Earth’s moon, which formed from a massive collision followed by fluid-like deformation, the Pluto-Charon system operates differently due to its icy composition.

This discovery, published in Nature Geoscience, could significantly alter how scientists understand the formation and evolution of planetary bodies in colder regions of the solar system. According to senior study author Erik Asphaug, the "kiss and capture" model not only accounts for how Charon was captured by Pluto but also accurately predicts its orbit, offering a more complete explanation for the Pluto-Charon system.