The lowest temperature – at least theoretically – is -273.15 degrees Celsius (-459.67 degrees Fahrenheit), or o degrees Kelvin. The latter is the SI unit of temperature named after Lord Kelvin, who devised his scale based on the laws of thermodynamics in 1848. At this point no more heat can be removed from a system as it has reached a stage of absolute cold.
The more heat an object has, the more its atoms move around and vice versa. As the temperature approaches absolute zero, atoms move very slowly and, in theory, at o degrees Kelvin there should be no movement, although according to experimental evidence there is some minimal vibrational motion.
The lowest temperature achieved by man was in a Massachusetts Institute of Technology (MIT) lab in 2003, where a cloud of sodium atoms was cooled to 0.45 nanokelvin, or less than half one-billionth of a degree Kelvin above absolute zero. The reason why it’s so difficult to achieve this temperature is because it requires an exponential amount of energy to continually lower the temperature to extreme cold – to the point that it needs an infinite amount of energy to reach absolute zero. Nevertheless, scientists are continually striving to find more efficient ways of achieving super-low temperatures because the strange effect they have on molecules can be extremely useful.
Superconductivity
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