# Is it possible to achieve absolute zero?

1. May 9, 2015

### William Henley

Is it possible to achieve absolute zero?

2. May 9, 2015

No!

3. May 9, 2015

### OCR

So it is...
http://en.wikipedia.org/wiki/Absolute_zero

4. May 9, 2015

### Staff: Mentor

Only if you do very poorly on your thermo exam.

Chet

5. May 10, 2015

### Thermo

But how is it possible that there is no place below -273 cantigrate degrees in the universe?

6. May 10, 2015

### davenn

why do you feel the need for there to be something at absolute zero ?

Did you read the link given in post #3 above explaining the conditions at absolute zero ?

Dave

7. May 10, 2015

### Thermo

There are empty areas between galaxies. I mean no any sun nearby not even 100000000000000000000 light year nearby. Aren't they even below -273,15?

Just because a chart that shows that volume is zero at absolute zero. I can't be convinced there isn't a -273 cEntigrade degrees out there. This volume thing at 0 point is not even experimental but a chart assumption.

8. May 10, 2015

### davenn

no, incorrect

about the coldest thing you will find out there is the cosmic microwave background which is about 3 Kelvin (ie. 3 deg above absolute zero)
This permeates the universe everywhere between the galaxies So it pretty much predetermines the coldest temperature you will find

Dave

9. May 10, 2015

### Thermo

You don't need to humiliate me. That's why students don't ask questions their mentors. Anyway, yea I've read it but then it is not polynomial degradation when you leave the sun to the outer space? Because you will achieve the 0 or even below if you do so.

10. May 10, 2015

### jbriggs444

Probably you are thinking of exponential degradation. That pattern arises when you have a hot object that transfers heat to an infinitely large cold reservoir and the rate of heat loss is proportional to the temperature difference. The hot object cools down and its temperature asymptotically approaches the temperature of the cold reservoir.

Given the cosmic microwave background at 3 degrees kelvin, the temperature that is approached is 3 degrees kelvin, not absolute zero.

11. May 10, 2015

Staff Emeritus
If you were asking questions, I'd have a little more sympathy. But you're not - you are making statements like "This volume thing at 0 point is not even experimental but a chart assumption." If you don't like being told your statements are wrong, maybe you should stop making wrong statements.

12. May 10, 2015

### Thermo

Our lecturer said it is because of the V-T chart. But maybe he didn't want to mention more. I am sorry for my behaviour didn't mean to make statements but tried to understand.

13. May 10, 2015

### OCR

14. May 10, 2015

### Neandethal00

ha ha , very funny answer.
But seriously, didn't absolute zero come from a theoretical vanishing 'volume' of gas or object?
How can anyone justify zero volume of anything? This tells us the theory breaks down before temperature reaches absolute zero.
Another way of saying, temperature below absolute zero is possible in an unknown state of matter.

15. May 10, 2015

### Staff: Mentor

No. Absolute zero has to do with temperature, not volume. It's perfectly possible to describe mathematically a system at absolute zero with finite volume.

16. May 10, 2015

### Staff: Mentor

What chart are you talking about? Do you have a reference?

17. May 10, 2015

### Staff: Mentor

Because there has to be a state of minimum possible energy. Absolute zero is that state.

18. May 10, 2015

Staff Emeritus
I think they are arguing that all we know about absolute zero came out of Charles' Law, as if no progress was made in the intervening two centuries.

19. May 10, 2015

### Staff: Mentor

Zero kelvin, or -273.15 centigrade, is the temperature at which the atoms/molecules that compose an object would be solely in their ground states. The ground state is the minimum energy level for that atom/molecule, so at absolute zero an object would have the least internal energy possible. There is literally no other internal energy for it to give up.

20. May 10, 2015

### ShayanJ

I think that's not the proper way of saying it. Its better to say, at absolute zero, by definition, particles will have zero energy. But because any system has a ground state energy which is greater than zero, no system can reach absolute zero.

21. May 11, 2015

Staff Emeritus
I'm sorry, but that's not correct. Drakkith's message is right.

22. May 11, 2015

### ShayanJ

No need to be sorry!
What I understand from he's message is that absolute zero is where the system(of course a system for which we can define temperature) is in its ground state. Now if we say absolute zero can't be reach, we're actually saying that we can't have such a system in its ground state even in principle. That seems wrong to me but maybe I'm just getting things wrong.
Also as far as I remember from thermodynamics, its the definition of absolute zero that the motion of all particles stop at this temperature which means zero energy.

Last edited: May 11, 2015
23. May 11, 2015

### Staff: Mentor

No, that's pretty much correct. It isn't possible for objects larger than atoms and perhaps small molecules to reach their ground state through thermodynamic means.

24. May 11, 2015

### ShayanJ

If you're talking about the 3rd law of thermodynamics(at least its Nernst's statement), then its about absolute zero, not the ground state. So what you're saying is equivalent to defining absolute zero as the temperature the object has when it is in its ground state. So this post actually is equivalent to your last post.

25. May 11, 2015

### Thermo

The chart I was talking about. It is not possible to reach that temperature in labs but we can estimate it is zero volume from the chart if we lenghten the line to the -273.15 centigrade degrees.