In [physics] and [engineering], cryogenics is the study of very low temperature (below −150 °C, −238 °F or 123 K), how those temperatures are reached, and what materials do at those temperatures on a quantum, atomic, and molecular level.

[cryogenicists|Scientists who study cryogenics] use the [Kelvin] scale as it is more precise. 0 on the [Kelvin] scale is known as [absolute zero].

Recently it was discovered that the temperature scale is in fact a [loop]: a gas was chilled to a temperature below [absolute zero] and the particles within that gas began behaving erratically, as if they were infinitely hot. This has lead to speculation as to the nature of [dark energy] and [http://www.mpg.de/6776082/negative_absolute_temperature|is nevertheless quite strange.]

There are a number of different applications of cryogenics within science.

[Cryobiology] is the study and practice of placing organisms very close to a state of [cryopreservation].

Cryobiology is distinct from [cryonics], in which organisms are fully frozen.

[Cryosurgery] is when only a specific part of an organism is frozen so as to remove a tumor or [wart removal|wart].

[Cryoelectronics] is a field of research involving the effects of extremely low temperatures upon electricity. These topics include [topological insulator|topological insulators], the [Quantum Hall effect], [2-dimensional gases], and [superconductivity]—when a substance is cooled below a critical temperature so that exactly zero [electrical resistance] occurs and all [magnetic fields] are [Meissner effect|expulsed].

[Cryotronics] is the [practical electronics|practical application] of cryoeletronics.

Cryogenics may also be used as source of [cryogenic propellant|fuel] and has applications within [Art Concept : Shattered|art] and [liquid nitrogen ice cream|culinary science].

Thanks to [Oneiromancer] for help elaborating cryolectronics.