Pluto likely acquired large moon Charon in a “kiss and capture” collision billions of years ago. It may have created a subsurface ocean on the icy 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!"

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.

Pluto likely acquired large moon Charon in a “kiss and capture” collision billions of years ago. It may have created a subsurface ocean on the icy dwarf planet.

Using simulations that took into account parameters like the size and composition of the bodies, along with the strength at which they collided, researchers reported that in the early stages of formation Charon and Pluto came together and orbited as one,

The reason that Pluto and Charon are so interesting is because Charon is 50% the size of Pluto,” said Adeene Denton, a planetary scientist at the University of Arizona who led the paper. “The only comparable system is Earth and its moon.