6
votes
3answers
231 views

If the universe is full of dark matter, why is it only 2.73 K cold?

people! I am just a physics layman, but I recently watched a documentary about the universe and it was told that the universe is full of dark matter and energy and the universe is empty, so that ...
2
votes
3answers
522 views

Less than absolute zero possible? [duplicate]

Possible Duplicate: Temperature below absolute zero? According to this article http://www.sciencemag.org/content/339/6115/52 (preprint: http://arxiv.org/abs/1211.0545) it is. What do you ...