The “demoted” dwarf planet Pluto and its largest moon Charon make an unusual pair, and for decades, scientists have been discussing how the binary system—in which each mutually orbits the other—came to be.

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

"We were definitely surprised by the 'kiss' part of kiss-and-capture. There hasn't really been a kind of impact before where the two bodies only temporarily merge before re-separating!"