" When the critical temperature is passed, the liquid has been converted directly into a permanent gas without discontinuity. The jelly has had no way of 'knowing' that the liquid within its meshes has become a gas. All that remains is to allow the gas to escape, and there is left behind a coherent aeorogel of unchanged volume. "

― Mark Miodownik , Stuff Matters: Exploring the Marvelous Materials That Shape Our Man-Made World