“IT’S an absolute. Mathematics has put speed limits on cooling, finally proving a century-old law – that unless you have infinite time and resources, you can’t get to the absolute zero of temperature. In 1906, German chemist Walther Nernst formulated the heat theorem, which states that as a perfect crystal approaches the absolute zero point of 0 kelvin (-273.15°C), the system’s entropy also goes to zero. This work earned him the 1920 Nobel prize in chemistry. The rule was controversial, with heavyweights like Albert Einstein and Max Planck debating it and introducing their own formulations. In 1912, Nernst defended his version by adding another clause, the unattainability principle, which states that absolute zero is physically unreachable. Taken together, these two rules make up the modern third law of thermodynamics. But because earlier arguments focused only on specific mechanisms or were crippled by questionable assumptions, some physicists have always remained unconvinced of its validity.”