Absolute zero is a temperature marked by a 0 entropy configuration. It is the coldest temperature theoretically possible and cannot be reached by artificial or natural means, because it is impossible to decouple a system fully from the rest of the universe. Temperature is an entropically defined quantity that effectively determines the number of thermodynamically accessible states of a system within an energy range. Absolute zero physically possesses quantum mechanical zero-point energy. Having a limited temperature has several thermodynamic consequences; for example, at absolute zero all molecular motion does not cease but does not have enough energy for transference to other systems. It is therefore correct to say that at 0 kelvin molecular energy is minimal.
By international agreement, absolute zero is defined as precisely 0 K on the Kelvin scale, which is a thermodynamic (absolute) temperature scale, and âˆ’273.15Â° on the Celsius scale. Absolute zero is also precisely equivalent to 0 R on the Rankine scale (same as Kelvin but measured in Fahrenheit intervals), and âˆ’459.67Â° on the Fahrenheit scale. Though it is not theoretically possible to cool any substance to 0 K, scientists have made great advancements in achieving temperatures close to absolute zero, where matter exhibits quantum effects such as superconductivity and superfluidity. For the kinematics of the molecules, on a larger scale, which is easier to understand see kinetic energy.