3 ms·
> But temperatures < 0K make no sense. Actually, they do! They behave very differently than you might expect. The reason is that temperature in thermodynamics
by jbay808 6y ago
> But temperatures < 0K make no sense.
Actually, they do! They behave very differently than you might expect. The reason is that temperature in thermodynamics is related to energy and entropy by dQ/dS = T, so if you can prepare a system that releases energy via decreasing in entropy, it has negative temperature. And, it turns out, you can actually do this. But the result is the complete opposite of cold.
https://en.m.wikipedia.org/wiki/Negative_temperature https://en.m.wikipedia.org/wiki/Negative_temperature
- cletus 6y agoThat is interesting. But it's worth pointing out that it's a slightly different definition of temperature that is "negative".
- jbay808 6y agoTime dilation also applies to a slightly different time than Newton's time. It turns out this is the more foundational definition of temperature, and the other one (average kinetic energy) is mostly a useful heuristic that matches well under certain conditions (like when the distribution of energy is close to the Boltzmann distribution), but not others (a very fast-moving baseball).