Minus 273.15K

[JHAQ]

Absolute zero is when all atomic or molecular motion stops & I understand it can never quite be reached as per the third law of thermodynamics. Even so , at absolute zero does all electron orbital motion also stop ( or can it ) . also what about the motion of the chilled mass thru space & around the sun or the galaxy ? Is this not motion too ?

[jsatan]

I'll find you a link about this as a strange thing happens at such low temp, all the atoms drop and sink to a single point like a black hole.

They cool the atoms with normal methods e.g. liquid nitrogen then use lasers to slow the atoms, using a magnetic trap to hold them, then slowly adjusting this trap to allow the "hot" atoms to break free just leaving the "cool" atoms which will then be even cooler.

 

Very strange.

[swansont]

I'll find you a link about this as a strange thing happens at such low temp' date=' all the atoms drop and sink to a single point like a black hole.

They cool the atoms with normal methods e.g. liquid nitrogen then use lasers to slow the atoms, using a magnetic trap to hold them, then slowly adjusting this trap to allow the "hot" atoms to break free just leaving the "cool" atoms which will then be even cooler.

 

Very strange.[/quote']

 

Liquid nitrogen is not involved. Lasers do the job quite nicely to get from room temperature down to microK temperatures. Evaporative cooling in the magnetic trap gets you down to a nK or thereabouts.

 

The final state is a Bose-Einstein condensate, and is nothing like a black hole. The atoms have the same state; they are not at the same point. In fact, their wave function is fairly large.

[swansont]

Absolute zero is when all atomic or molecular motion stops & I understand it can never quite be reached as per the third law of thermodynamics. Even so , at absolute zero does all electron orbital motion also stop ( or can it ) .

 

No. Absolute zero theoretically has all center-of-mass motion of atoms and molecules stopping. But, as you note, it is unattainable.

[budullewraagh]

there is a physics principle that states that at absolute zero, an unreachable number by thermodynamical and mathematical principles, electrons move

[jsatan]

The information I was reading said they used a conventional way to cool the atoms first then used the lasers, the black hole was just an example of how they fall to a single point, I'm only going what I've read. I'll find it then you can read it too.

[swansont]

The information I was reading said they used a conventional way to cool the atoms first then used the lasers, the black hole was just an example of how they fall to a single point, I'm only going what I've read. I'll find it then you can read it too.

 

I don't need to. I know and work with people who have done BEC, and I do laser cooling (to "only" a few microK) on a regular basis.

 

I suspect the journalist involved was misunderstanding and/or sensationalizing the phenomena. Imagine that...