The series premiered on demand on November 23, 2015, and on Syfy on December 14, 2015. A 13-episode second season premiered on February 1, 2017. In March 2017, Syfy renewed The Expanse for a 13-episode third season to air in 2018.
Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian.
Corallite: The corallite is the cup-like skeleton made by a coral polyp. To measure the corallite diameter, one measures from one wall of the corallite across to the other. The blades standing up inside the corallite are known as septa. The septa are called costae outside the corallite walls.