New Horizons probes the mystery of Charon's red pole
Charon’s polar regions are very cold, and I mean VERY cold! These temperatures (especially with Charon’s extremely thin atmosphere) are too cold to support surface liquid: gases are deposited straight to solids, and solids sublimate directly to gases. So—unlike at Charon’s warmer equator—any gases that arrive on the winter pole would freeze solid instead of escaping, a process scientists refer to as cold trapping. Carly Howett Credit: JHUAPL/SwRI This new substance is called a tholin, and has been made in similar conditions in laboratories here on Earth. haron likely has gradually built up a polar deposit over millions of years as Pluto’s atmosphere slowly escapes, during which time the surface is being irradiated by the sun.