Absolute zero

Zero kelvin (−273.15 °C) is defined as absolute zero. Absolute zero is the lowest limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reach their minimum value, taken as zero kelvin. The fundamental particles of nature have minimum vibrational motion, retaining only quantum mechanical, zero-point energy-induced particle motion. The theoretical temperature is determined by extrapolating the ideal gas law; by international agreement, absolute zero is taken as −273.15 degrees on the Celsius scale (International System of Units), This value was not immediately accepted; values ranging from to, derived from laboratory measurements and observations of astronomical refraction, remained in use in the early 20th century.
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