The lowest temperature theoretically achievable by a system, absolute zero is the point at which substances possess no thermal energy. In 1848, British physicist Lord Kelvin devised a temperature scale that set absolute zero, or 0°K, at -273.15°C. Although absolute zero is impossible to achieve, scientists have brought some substances within a billionth of a degree of 0°K, inducing in these materials odd quantum effects such as superconductivity. Where is the coldest known place in the universe? Discuss