Scientists propose Pluto and its moon Charon formed through a "kiss and capture" event 4.5 billion years ago, challenging previous theories about their unique size ratio and orbital relationship.

Unlike Earth, where the Moon orbits the planet, Pluto and Charon orbit each other, forming a binary system that is more similar to the Earth-moon system than any other moon in the solar system.

Simulations suggest Pluto and its largest moon may have gently stuck together for a few hours before Charon settled into a stable orbit around the dwarf planet