Jääjättiläiset

Jääjättiläiset, meaning "ice giants" in Finnish, is a term often used in popular culture and sometimes in informal scientific discussions to refer to a category of planets. These planets are characterized by a significant composition of volatile substances like water, ammonia, and methane, in addition to a rocky core. They are larger than terrestrial planets but smaller than gas giants like Jupiter and Saturn.

The concept of ice giants is primarily associated with the planets Uranus and Neptune in our solar system. Unlike the gas giants, which are dominated by hydrogen and helium, Uranus and Neptune have a denser internal structure with a substantial proportion of "ices." These volatiles are thought to exist in various states, including liquid and supercritical fluid, under the immense pressures and temperatures found within these planets.

The formation of ice giants is believed to have occurred in the outer regions of protoplanetary disks, where temperatures were low enough for volatile compounds to condense and accumulate. Their mass and composition differentiate them from both smaller rocky planets and the much larger gas giants. While the term is descriptive, it's important to note that the exact internal structure and composition of these planets are still areas of active research and ongoing scientific investigation. The term "ice giant" is more of a descriptive classification than a strictly defined scientific category in all contexts.