University of Arizona

Pluto may have an icy sea beneath its surface

The papers seek to explain why Sputnik Planitia -- a 1,000 kilometer-wide, nitrogen-covered basin in Pluto's heart-shaped northern region -- is permanently aligned with the dwarf planet's moon Charon.

The first paper, from the University of Arizona,suggests that Sputnik Planitia filled with ice and altered tidal forces between Pluto and Charon.