Re: What happens at Absolute Zero?

Race

The temperature of an object is a measure of how much energy that object has. 
This energy can be gained from thermal sources or other methods  such as 
nuclear processes or collisions with other objects. At absolute zero (0K) the 
object, atom or molecule, simply has no excess energy. Only that which it 
inherently possesses. Called the `ground zero state'. Each electron, proton 
and neutron is at its lowest permissible energy level. So atoms and molecules 
do continue to exist at 0K and they are still uniquely different. As they lack 
extra energy they are very unlikely to actually interact wth anyhting though. 
As yet no one has actually cooled anything to zero Kelvin but they have 
reached a few thousandths of a degree above zero Kelvin. Some elements and 
certain specially designed ceramic materials do behave in strange and 
unexpected ways when their temperature is very low.

You may be interested in some of the weird and wonderful things that do 
happen at low temperatures. To fully understand what happens at low 
temperatures requires a knowledge of Statistical Thermodynamics and Quantum 
Theory so I can really only give you a brief overview of some of this. Also. 
I really do not fully understand all of this either, it is a field of study in 
itself.

1.Superfluidity 

When Helium-3  is cooled to below 3K, or below a few thousandths of a degree 
Kelvin for helium-4, it becomes a super-fluid. This means it loses its viscosity
and so has no resistance, so to speak. The helium fluid can then escape through 
any container as it can flow between any gap in the container. 

If the Helium fluid is in a rotating container then vortices are seen just 
after super-fluidity occurs. This is thought to be a case of a 
Bose-Einstein 
Condensate and macroscopic quantum behaviour. This may also have an impact 
on Cosmology. The direction of the vortices are independent of where the 
experiment is carried out. They appear to be rotating with respect to the 
Universe. This is generally thought not to be allowed.

2. Super-conductors 
 Some materials become super-conductors at very low temperatures. This means 
they lose all electrical resistance and are perfect electrical conductors. 
Follow the link to learn a little more. These would be very useful to 
electrical companies. 

3. Bose-Einstein 
Condensates:

Certain atoms are what are called 
Bosons. This 
means each atoms quantum state can be the same as its neighbours. In which 
case large amounts of certain elements, Helium and Rubidium,  behave as if 
they are one single atom. 

If you wish to know more about the fascinating world of Low Temperature 
Physics I would recommend doing a web search on the key words I have used 
above. There are precious few non-technical books on this subject. The 
technical books are all horrendously complicated, it gives me headache just 
thinking about it!