eli5: Why is it temperatures can go up to the trillions but only down to -273?
In: Physics
While most answers so far here have been correct (at absolute zero, i.e. 0 K or roughly -273 C, a system has the minimum possible amount of energy in its molecules’ movement), there actually is a negative temperature (less than 0 K) in thermodynamics. This comes up when you define temperature not as the average energy of the particles of a body, but as the required heat (i.e. energy) transfer into a system to change its entropy. It is possible to have systems where the entropy decreases if you add any more energy, which means you have a negative absolute temperature. These systems contain _more_ energy than systems with a positive temperature, so in that sense a system with negative absolute temperature is _hotter_ than a system with positive temperature.
https://en.wikipedia.org/wiki/Negative_temperature
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