Hi,

 

Even wonder what will really happen when things hit the absolute zero ,i.e. -273.15*C , I know all atomic motion stops but what will be seen macroscopically.

 

 

cheers

What do you mean? All atomic motion would, in theory, stop. However you can never reach absolute zero, it is impossible, so lets not guess.

What do you mean? All atomic motion would, in theory, stop. However you can never reach absolute zero, it is impossible, so lets not guess.

 

Well that is based upon the fact that at absolute zero you would know the exact location and momentum of electrons which would break the rules of the Heisenberg Uncertainty principle. I think it's a better idea to say 'We may reach absolute zero, but we'll never be able to tell that we did as the act of making a measurement will bring whatever we're measuring above absolute zero.'

'We may reach absolute zero, but we'll never be able to tell that we did as the act of making a measurement will bring whatever we're measuring above absolute zero.'

So all we have to do is separate information from energy(states) so we can transfer information wihtout transferring energy.

actually i remember once hearing of a theory that stated that theoretically, electrons would keep moving if absolute zero were reached

Well that is based upon the fact that at absolute zero you would know the exact location and momentum of electrons which would break the rules of the Heisenberg Uncertainty principle. I think it's a better idea to say 'We may reach absolute zero, but we'll never be able to tell that we did as the act of making a measurement will bring whatever we're measuring above absolute zero.'

 

According to quantum mechanics if you cannot observe it you cannot say it exists.

 

But the Third Law of Thermodynamics (combinded with the Second) say that absolute zero can only be approached as a limit and never obtained.

Maybe we could reach the absolute zero some time later. Who knows?

heisenburg and the laws of physics. we will never reach absolute zero.

unless you change the laws of physics

 

How cold can we get something down to. eg freezing helium without pressure

helium needs pressure to freeze. its still liquid at at standard pressure when the temp is a few picokelvin. the damn stuff just won't freeze

I know we reached 450 picokelvin:

http://www.google.co.uk/search?hl=en&safe=off&q=450+picokelvin+to+kelvin&meta=

that was for a BEC (Bose-Einstein condensate).