In a groundbreaking study, scientists have uncovered a new theory explaining the origin of Charon, Pluto's largest moon.
Billions of years ago, two icy worlds in the Kuiper Belt collided in what researchers now call a "kiss and capture" event. Instead of obliterating each other or merging, the two bodies briefly stuck together before separating to form the binary system of Pluto and Charon we observe today.
Pluto and Charon: Scientists Uncover Unique 'Kiss and Capture' Collision Origins
The research, conducted by a team at the University of Arizona's Lunar and Planetary Laboratory, sheds light on how celestial bodies in the frigid outer reaches of the solar system form and evolve.
Led by NASA postdoctoral fellow Adeene Denton, the team used advanced simulations to examine the collision.
Their findings, published in Nature Geoscience, challenge previous theories about the Pluto-Charon system's formation.
For decades, scientists believed that Charon formed through a process similar to Earth's moon — an immense collision that caused the colliding bodies to behave like molten, fluid-like materials.
While effective for Earth's system, this model failed to account for the icy and rigid nature of smaller, colder bodies like Pluto and Charon.
When Denton's team factored in the structural strength of rock and ice, a new picture emerged, PhysOrg said.
Their simulations showed that the two bodies briefly rotated as a single, snowman-shaped object during the collision before separating. The result was a stable binary system where Pluto and Charon orbit a common center of gravity.
"What's unique about this process is the brief merger," Denton explained. "Pluto and Charon collided, stuck together for about 10 hours and then separated. This scenario, which we call 'kiss and capture,' is unlike any other collision model we've seen."
Charon's Unusual Size Unveils Pluto's Binary Planet Mystery
According to Space, Charon's size relative to Pluto adds to the mystery. Measuring half of Pluto's diameter and possessing about 12% of its mass, Charon is unusually large compared to its parent body. For comparison, Earth's moon is only about a quarter the size of Earth.
This size ratio makes the Pluto-Charon system a rarity, often referred to as a binary planet system.
The study also revealed that the collision likely deposited significant heat into both bodies. This heat could explain the formation of a subsurface ocean on Pluto, a feature previously thought to require radioactive heating from an earlier period in the solar system's history.
Looking ahead, the team plans to explore whether similar processes could explain the formation of other binary systems in the Kuiper Belt. They also aim to investigate how the collision influenced Pluto's geological features, including its icy plains and towering mountains.
