Here's why:
* Their center of mass lies outside both bodies: The barycenter, the point around which both objects orbit, is located in space between Pluto and Charon. This is a key characteristic of a double planet system.
* Similar size: Charon is about half the size of Pluto, which makes it significantly larger than most moons compared to their planets.
* Mutual orbit: Both bodies orbit a common center of mass, rather than Charon orbiting Pluto.
While some scientists consider Pluto and Charon a double planet, others still classify Charon as a moon due to the vast difference in their masses. However, the unique relationship between these two celestial bodies sets them apart from other planet-moon systems.
