To be pedantic, it's impossible to get to 0K due to quantum fluctuations. Even empty deep space is over 2K. In laboratory settings, we've gotten way below 1K. I don't think anything qualifies as a gas at that temperature. It'd be a solid or a BEC.

This is true, but doesn't have anything to do with quantum mechanics -- the third law of thermodynamics is basically a statement that you can't cool things to absolute zero.

Your input caused me to google a video about this:

https://www.youtube.com/watch?v=kswiDQ2aAKA

Very intereting!

Helium does not solidify down to the lowest temperatures that have been achieved (at standard pressure). Though it does become a superfluid, which is a distinct phase of matter from a gas/liquid.

BE condensate https://en.wikipedia.org/wiki/Bose%E2%80%93Einstein_condensa...

0K implies no Brownian motion at all (no thermal energy), so there would be no force to keep the molecules apart.

Actually, in some substances the molecules are further apart in the solid than they are in the liquid phase.

Intuitively I would think so since 0K is a motionless state. By definition everything would be solid because nothing would be capable of e.g. filling a given volume, or for that matter, doing any action at all.

But this isn't my field of expertise.

Complete lack of motion would violate Heisenberg uncertainty principle ("no motion" == "I know both momentum and location with zero uncertainty" and that's not allowed)

No, you can have zero momentum. However it comes along with having a position wavefunction that fills the whole universe.

> However it comes along with having a position wavefunction that fills the whole universe.

I love that this sentence exists. Because it's absurd and enlightening at the same time.

The universe kindly requests that you do not divide by zero.

Because it does not want to be Bourne Again.

Hey let's probe the boundary conditions of the universe.

The boundary condition is that at some arbitrary point god smacks you and tells you to knock it off

Have you ever played The Talos Principle? This is pretty much what happens if you try to walk outside the playable game area: https://www.youtube.com/watch?v=vWjUzvLk58o

Sorry God!

Careful now, you don't want to crash the simulation.

It already slows down when you are moving too fast.

Precisely. But that doesn't work for OP's question since the whole universe isn't at 0K.