What keeps Pluto's ocean from freezing?

When NASA's New Horizons spacecraft flew past Pluto in 2015, researchers hoped that its data would help them unravel some of the dwarf planet's mysteries. Instead, the discoveries made during the close-up look at Pluto and its moon Charon revealed more questions that needed answering.

Ancient scars on Pluto and Charon reveal distant space objects

When the New Horizons mission conducted the closest flyby of Pluto and its moon, Charon, in 2015, images provided a zoomed-in view of their pockmarked surfaces. The scars are ancient impact craters that were created 4 billion years ago.