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Can you reach absolute zero in complete empty space 
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#1
Jan1513, 01:16 AM

P: 17

Ok, so I know that the laws of physics say reaching absolute zero temperature is impossible, but suppose we took a box that was perfectly insulated in completely empy space, and I took all the particles out of it to create a vacuum. Now, since there are no particles in the box, then wouldn't the temperature inside the box be absolute zero (no heat energy = no temperature, right?)? If I am wrong, what would the temperature inside the box be? Since the average temperature of the universe is only 2.73 kelvin, then it seams like there would be areas in space that are like this....



#2
Jan1513, 02:25 AM

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What does "temperature" measure?



#3
Jan1513, 06:51 PM

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The concept of temperature deals with systems where the number of particles is large enough to approximate the density of states as a continuous function of energy. If you get to small number of particles, then the discrete nature of states becomes important, and temperature ceases to have any meaning.



#4
Jan1513, 07:48 PM

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Can you reach absolute zero in complete empty space
I suppose one may choose to attribute a characteristic temperature to the zeropoint energy in a volume, by E=kT or whatever, but it is not clear what this would mean, hence the question in post #2.
Focussing on what temperature is should help. 


#5
Jan1613, 11:30 AM

P: 54

How about colder than absolute zero?
http://www.livescience.com/25959ato...lutezero.html BTW  'empty space' is not empty. 


#6
Jan1613, 11:40 AM

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#7
Jan1613, 12:18 PM

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#8
Jan1613, 12:44 PM

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#9
Jan1613, 01:33 PM

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#10
Jan1613, 05:58 PM

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Do you mean that temperature need not decrease with the particle density? 


#11
Jan1613, 06:04 PM

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#12
Jan1613, 06:38 PM

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I was just presenting a factoid that I though the OP might find interesting because he was talking about temperature and a hard vacuum. Let me restate it
Hm ... I don't see any way to restate it and make it any more clear that what I already said: It is my understanding that there are dust clouds that have a "temperature" of millions of degrees and yet they are a hard vacuum compared to what we can get in a vacuum chamber on earth. 


#13
Jan1613, 07:09 PM

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