E-Mail IMAGE: Dissociation pressures of various clathrate hydrates across a range of cryogenic temperatures. The upper regions of each curve indicate stable boundaries of the clathrate hydrates. (Similar colors have been used... view more Credit: 2021 Hideki Tanaka, Okayama Univ. Just like on Earth, water on other planets, satellites, and even comets comes in a variety of forms depending on multiple factors such as pressure and temperature. Aside from the gaseous, liquid, and solid states we are accustomed to, water can form a different type of crystalline solid called clathrate hydrate. Although they look similar to ice, clathrate hydrates have actually small water-based cages in which smaller molecules are trapped. These trapped "guest" molecules are essential for preserving the crystalline structure of clathrate hydrates, which would otherwise "collapse" into regular ice or water.