absolute zero

Lowest temperature theoretically possible according to kinetic theory, zero kelvin (0 K), equivalent to −273.15°C/−459.67°F, at which molecules are in their lowest energy state. Although the third law of thermodynamics indicates the impossibility of reaching absolute zero, in practice temperatures of less than a billionth of a degree above absolute zero have been reached. Near absolute zero, the physical properties of some materials change substantially; for example, some metals lose their electrical resistance and become superconducting.