# absolute zero **URL:** \ **Category:** Factual Questions\ **Created:** [September 30, 2003, 5:22am UTC](https://boards.straightdope.com/t/absolute-zero/204644 "2003-09-30T05:22:00Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![stuffusbus](https://avatars.discourse-cdn.com/v4/letter/s/a183cd/32.png) [@stuffusbus](https://boards.straightdope.com/u/stuffusbus)\ **Post date:** [September 30, 2003, 5:22am UTC](https://boards.straightdope.com/t/absolute-zero/204644/1 "2003-09-30T05:22:00Z")
Im sure most of you know alot more than me about absolute zero than me, but from what i can remember is that it would be so cold that all movement of electrons would stop. So if all movement of the electrons would stop, what would happen? Ive always wondered about it and i wondered what theories you guys could come up with. ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [September 30, 2003, 5:24am UTC](https://boards.straightdope.com/t/absolute-zero/204644/2 "2003-09-30T05:24:32Z")
Actually there is still some motion of subatomic particles at absolute zero, however, all motion of the atoms themselves does stop. (Relatively speaking.) One interesting phenomenon of matter cooled to near absolute zero is the [Bose-Einstein Condensate](http://www.wikipedia.org/wiki/Bose-Einstein_condensate). ---
**Author:** ![Lobsang](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lobsang/32/4067_2.png) [@Lobsang](https://boards.straightdope.com/u/Lobsang)\ **Post date:** [September 30, 2003, 5:27am UTC](https://boards.straightdope.com/t/absolute-zero/204644/3 "2003-09-30T05:27:32Z")
It never occured to me that the subatomic particles keep moving. Does that count as energy? would it be possible for the subatomic particles to stop moving? ---
**Author:** ![MonkeyMensch](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@MonkeyMensch](https://boards.straightdope.com/u/MonkeyMensch)\ **Post date:** [September 30, 2003, 6:22am UTC](https://boards.straightdope.com/t/absolute-zero/204644/4 "2003-09-30T06:22:04Z")
I seem to recall an article regarding negative absolute temperatures, something regarding quantum states near ablsolute zero. I page the SDMB’s resident physicists at this point… ---
**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\ **Post date:** [September 30, 2003, 9:54am UTC](https://boards.straightdope.com/t/absolute-zero/204644/5 "2003-09-30T09:54:32Z")
Wait a second, electrons would stop? I was taught it is Brownian motion which ceases at absolute zero… Is it true that electrons stop? Would they then fall into the nucleus, as a result? - Jinx ---
**Author:** ![MC\_Master\_of\_Ceremonies](https://avatars.discourse-cdn.com/v4/letter/m/bb73d2/32.png) [@MC\_Master\_of\_Ceremonies](https://boards.straightdope.com/u/MC_Master_of_Ceremonies)\ **Post date:** [September 30, 2003, 12:49pm UTC](https://boards.straightdope.com/t/absolute-zero/204644/6 "2003-09-30T12:49:47Z")
Electrons still oscillate at absolute zero due to zero point energy, infact at absolute zero matter should undergo a phase transistion as it becomes entirely governed by quantum fluctuations. Bosons as they tend to absolute zero go into an interesting state called a Bose-Einstein condensate, IIRC fermions can sometimes do this as well by forming partnerships with other fermions. ---
**Author:** ![g8rguy](https://avatars.discourse-cdn.com/v4/letter/g/7cd45c/32.png) [@g8rguy](https://boards.straightdope.com/u/g8rguy)\ **Post date:** [October 1, 2003, 12:16am UTC](https://boards.straightdope.com/t/absolute-zero/204644/7 "2003-10-01T00:16:07Z")
In fact, even at absolute zero, electrons move around pretty good. Most standard quantum mechanics is at absolute zero because it’s easier that way, and for a heavy atom like uranium or mercury, the inner electrons are actually relatavistic. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [October 1, 2003, 12:24am UTC](https://boards.straightdope.com/t/absolute-zero/204644/8 "2003-10-01T00:24:51Z")
Interestingly, near absolute zero, electrons begin to smear out and become large and fuzzy. The reason is the Heisenberg Uncertainty Principle, which states that certain pairs of measurements cannot both be made to arbitrary precision. So, since the electron’s velocity at 0 K can be known precisely, it smears out so it’s position is indeterminate. ---
**Author:** ![bonzer](https://avatars.discourse-cdn.com/v4/letter/b/45deac/32.png) [@bonzer](https://boards.straightdope.com/u/bonzer)\ **Post date:** [October 1, 2003, 12:25am UTC](https://boards.straightdope.com/t/absolute-zero/204644/9 "2003-10-01T00:25:07Z")
For that matter, even atoms can remain in motion in the limit towards absolute zero. Liquid helium never freezes. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [October 1, 2003, 12:42am UTC](https://boards.straightdope.com/t/absolute-zero/204644/10 "2003-10-01T00:42:08Z")
> [@](#): > > \*Originally posted by bonzer \* > \*\*For that matter, even atoms can remain in motion in the limit towards absolute zero. Liquid helium never freezes. \*\* That’s not entirely true. Helium will solidify when chilled to within a few degrees of absolute zero under a pressure of 20 atmospheres or more. But at normal ambient pressure, you’re correct. ---
**Author:** ![bonzer](https://avatars.discourse-cdn.com/v4/letter/b/45deac/32.png) [@bonzer](https://boards.straightdope.com/u/bonzer)\ **Post date:** [October 1, 2003, 1:00am UTC](https://boards.straightdope.com/t/absolute-zero/204644/11 "2003-10-01T01:00:58Z")
And you’re correct at non-ambient pressures. ---
**Author:** ![DarrenS](https://avatars.discourse-cdn.com/v4/letter/d/977dab/32.png) [@DarrenS](https://boards.straightdope.com/u/DarrenS)\ **Post date:** [October 1, 2003, 2:51am UTC](https://boards.straightdope.com/t/absolute-zero/204644/12 "2003-10-01T02:51:30Z")
> [@](#): > > \*Originally posted by g8rguy \* > \*\*In fact, even at absolute zero, electrons move around pretty good. Most standard quantum mechanics is at absolute zero because it’s easier that way, and for a heavy atom like uranium or mercury, the inner electrons are actually relatavistic. \*\* **gr8rguy** - I know you know what you’re talking about, but this left me scratching my head. Do you mean _theoretical_ QM is at Absolute Zero? I thought we still hadn’t reached true AZ - even though we’ve approached it to within billionths(?) of a degree. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [October 1, 2003, 3:07am UTC](https://boards.straightdope.com/t/absolute-zero/204644/13 "2003-10-01T03:07:48Z")
He must mean theoretical. In fact, it _is_ impossible to actually achieve 0 K, since no system can can be 100% isolated from the rest of the universe. Some energy will always leak in somehow and keep the temperature above absolute zero. ---
**Author:** ![g8rguy](https://avatars.discourse-cdn.com/v4/letter/g/7cd45c/32.png) [@g8rguy](https://boards.straightdope.com/u/g8rguy)\ **Post date:** [October 1, 2003, 4:48am UTC](https://boards.straightdope.com/t/absolute-zero/204644/14 "2003-10-01T04:48:42Z")
Yes, I mean theory; experiment is always at some finite temperature, as **Q.E.D.** says, although that temperature can sometimes be so close to absolute zero that there’s no point in worrying about it or not. There’s no fundamental problem with doing QM at some non-zero temperature, but it’s a bit more complicated, so when you solve your text-book solutions to the harmonic oscillator or the hydrogen atom or some such, you’re implicitly doing things at 0 K.