What are 8 facts about Dione?

Dione is one of Saturn's moons and is primarily composed of water ice and rocky material. It has a diameter of about 1,123 kilometers (697 miles) and features a mix of bright, icy regions and darker, heavily cratered areas. Dione exhibits a unique surface with large, bright fractures, suggesting tectonic activity in its past. It also has a thin atmosphere composed mainly of oxygen and is believed to have a subsurface ocean, making it a point of interest for astrobiological studies.