Definition: Absolute zero
is the lowest possible temperature
, at which point the atoms of a substance transmit no thermal energy - they are completely at rest. It is 0 degrees on the Kelvin scale, which translates to -273.15 degrees Celsius (or -459.67 degrees Fahrenheit).
The concept of an "absolute cold" was first presented by Robert Boyle in his 1665 New Experiments and Observations touching Cold. Various physicists explored this phenomenon, until Lord Kelvin derived his thermodynamic temperature scale, extrapolating backward to absolute zero based purely on the laws of thermodynamics.
Some substances, when cooled to near-absolute zero temperatures, reach a state of matter known as a superfluid, which exhibit strange properties.