New "Kiss-and-Capture" Theory Explains Pluto's Formation of Largest Moon, Charon

A new theory has emerged to explain how Pluto may have captured its largest moon, Charon, billions of years ago through a unique "kiss-and-capture" collision. The process, proposed by researchers, suggests that two icy bodies in the Kuiper Belt collided, briefly merged into a spinning "cosmic snowman," and then separated to form the Pluto-Charon system. This scenario, which lasted around 10 hours, challenges previously established theories and offers a new perspective on moon formation in the distant regions of the solar system.

Collision Dynamics in the Kuiper Belt

According to a study published in Nature Geoscience, Pluto and Charon's interaction likely occurred in the Kuiper Belt, a region filled with icy bodies at the solar system's edge. As reported by space.com, the research team, led by Adeene Denton, a lunar and planetary researcher at the University of Arizona and NASA postdoctoral fellow, believes that the collision involved material strength rather than fluid dynamics, as these bodies are composed of ice and rock.

Denton explained to Space.com that the process, referred to as "kiss-and-capture," occurred when the two bodies briefly merged before separating again. This differs from traditional planetary collision scenarios like "hit and run" or "graze and merge," where either a permanent merger or complete separation occurs.

The Formation of the Pluto-Charon System

Charon, which is about half the size of Pluto and 12 percent of its mass, is considered unusually large compared to other moons. Its formation has been linked to a significant collision event, similar to the theory of Earth's moon forming after a massive impact. During this icy encounter, Charon could not penetrate deeply enough into Pluto to merge due to the structural strength of both bodies. This caused the two to separate but remain gravitationally linked, with Charon eventually moving into a stable orbit around Pluto.

Implications for Kuiper Belt Objects

The findings, according to the study, may also shed light on how other large moons in the Kuiper Belt, such as those of Eris and Orcus, could have formed through similar processes. The research team plans to explore this mechanism further and investigate Charon's long-term tidal evolution to confirm the theory.