What is the coldest temperature possible?

The answer

Absolute zero, 0 Kelvin (−273.15°C), is the theoretical lowest temperature where all molecular motion stops. It can never be fully reached due to the third law of thermodynamics, but scientists have cooled atoms to within billionths of a degree above it. At these extreme temperatures, matter enters exotic quantum states like Bose-Einstein condensates, where thousands of atoms behave as a single quantum entity and display bizarre properties like superfluidity.