That’s not what an absolute scale is tho. It’s just because of the second law of thermo. -10 K would never be 10 K (maybe that’s the joke? I don’t get it. Maybe it was intended as an absolute/absolute pun). Either way, to me did not make sense.
Further, based on this article it seems rather correct to tie negative Kelvin to actual temperatures, considering it’s been experimentally achieved…
CheezyWeezle@lemmy.world 5 months ago
What makes you say that isn’t what an absolute scale is? It definitely is what an absolute scale is. For example, distance is measured on an absolute scale. Negative ten meters would be equal to positive ten meters. In the classic definition of temperature measuring the total kinetic energy of matter, a negative temperature would be equivalent to a positive temperature, as it is measuring how much the particles are moving. Similar to velocity (also an absolute scale), if a particle is moving at a particular speed, X, then moving at that same speed backwards would be -X, but it is still the same speed.
Negative temperatures are used to express something different from the classic definition of temperature, because the particles are not doing less than zero movement. Once a particle reaches absolute zero, it cannot move any less, but it can still have other properties that are directly tied to temperature change. Therefore, if purely expressing the classic definition of temperature, a negative temperature cannot exist, so any negative temperature would necessarily have to be equivalent to the same positive temperature. Of course, in any actual scientific conversation, the classic definition of temperature would be understood to be inadequate.
GiveMemes@jlai.lu 5 months ago
Go read the article. Temperature is dependent on all energy, not just kinetic. You’re very sure of yourself for somebody so incredibly incorrect.
CheezyWeezle@lemmy.world 5 months ago
Maybe you should go read the article and actually read my comment. The article literally agrees with everything I said within the first few paragraphs. Negative temperatures do not and cannot exist under the classical definition, but the overall state of a system can reach a configuration that behaves like a negative temperature would, yet this is achieved by raising the temperature above what would tend towards infinity. Once again, it can be useful to represent certain configurations of systems of matter as a negative temperature with added context, and that’s why negative temperatures are a thing in science. It’s also why there are things like the summation of all natural numbers (1+2+3+4+…) being equal to -1/12. If you actually add up the natural numbers you get infinity, but ignoring that can yield useful results.
You are also absolutely wrong about temperature being dependent on all energy. Temperature is literally defined as the measurement of kinetic energy in a system. Are you actually suggesting that if I put an apple on an elevator, it’s temperature is going to be increased when I send it up? Or that if I inject that apple with cold diesel fuel it will heat up? Those things would increase the energy of the apple, but not increase the kinetic energy and therefore the temperature does not rise.
GiveMemes@jlai.lu 5 months ago
From the article (which you clearly either didn’t read or didn’t understand):
“Temperature, however, relates not only to kinetic energy, but to the total energy of the particles, which in this case includes interaction and potential energy.”
“The inverted Boltzmann distribution is the hallmark of negative absolute temperature; and this is what we have achieved,” says Ulrich Schneider. “Yet the gas is not colder than zero kelvin, but hotter,” as the physicist explains: “It is even hotter than at any positive temperature – the temperature scale simply does not end at infinity, but jumps to negative values instead.”
“At first sight it may sound strange that a negative absolute temperature is hotter than a positive one. This is simply a consequence of the historic definition of absolute temperature, however; if it were defined differently, this apparent contradiction would not exist.”
“Temperature, however, relates not only to kinetic energy, but to the total energy of the particles, which in this case includes interaction and potential energy. The system of the Munich and Garching researchers also sets a limit to both of these. The physicists then take the atoms to this upper boundary of the total energy – thus realising a negative temperature, at minus a few billionths of a kelvin.”
Again, very sure of yourself for being so incredibly incorrect…