Charon, the moon of Pluto, currently rotates once every 153.3 hours, but in the past it rotated much faster at 14.3 hours. A research team from the California Institute of Technology in Los Angeles, USA and the Swiss Federal Institute of Technology in Zurich confirmed this through analysis of mountain ranges on Charon's surface. The crescent-shaped mountain ranges in Charon's Oz Terra region were formed by compression stress caused by a decrease in past rotational speed, allowing for the calculation of the initial rotation period. This study supports evidence for the 'cold start' scenario, which suggests that Charon was formed from a very cold state initially. It also provides important clues to understanding the early evolution and orbital history of other icy moons in the outer solar system.
