Absolute zero, aka 0 Kelvins, and equal to -273.15 C is not an approximation. It is a limit, like the speed of light is a limit. And even theoretically, matter can never be cooled to that point. There simply is no way to completely stop all the sub-microscopic movement.

But they have gotten pretty close -- a few millikelvins from 0K.

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. . . don't mind me, I'm starting to prep for my classes. Can you tell? wink

Do you know the most surprising thing about divorce? It doesn't actually kill you, like a bullet to the heart or a head-on car wreck. It should. When someone you've promised to cherish till death do you part says, "I never loved you," it should kill you instantly.

- Under the Tuscan Sun